{"id":34005,"date":"2022-10-05T14:31:59","date_gmt":"2022-10-05T07:31:59","guid":{"rendered":"https:\/\/www.vnras.com\/drug\/?p=34005"},"modified":"2022-10-05T14:37:02","modified_gmt":"2022-10-05T07:37:02","slug":"cac-nguyen-ly-quan-trong-cua-laser","status":"publish","type":"post","link":"https:\/\/vnras.com\/drug\/cac-nguyen-ly-quan-trong-cua-laser\/","title":{"rendered":"C\u00e1c nguy\u00ean l\u00fd quan tr\u1ecdng c\u1ee7a laser khi d\u00f9ng tr\u00ean da"},"content":{"rendered":"

CH\u01af\u01a0NG 3: C\u00c1C NGUY\u00caN L\u00dd QUAN TR\u1eccNG C\u1ee6A LASER<\/p>\n

Bi\u00ean d\u1ecbch: Bs. Tr\u01b0\u01a1ng T\u1ea5n Minh V\u0169<\/p>\n

\u0110\u1ec3 t\u1ea3i file PDF C\u00e1c nguy\u00ean l\u00fd quan tr\u1ecdng c\u1ee7a laser<\/a>, h\u00e3y click t\u1ea1i \u0111\u00e2y<\/a>.<\/p>\n

L\u00fd thuy\u1ebft n\u00e2ng cao v\u1ec1 quang nhi\u1ec7t ch\u1ecdn l\u1ecdc<\/strong><\/h2>\n

Trong \u201cCh\u01b0\u01a1ng 1\u201d ch\u00fang ta \u0111\u00e3 xem x\u00e9t l\u00fd thuy\u1ebft quan tr\u1ecdng nh\u1ea5t li\u00ean quan \u0111\u1ebfn laser<\/strong> l\u00e0 l\u00fd thuy\u1ebft v\u1ec1 qu\u00e1 tr\u00ecnh quang nhi\u1ec7t c\u00f3 ch\u1ecdn l\u1ecdc. Tuy nhi\u00ean, trong th\u1ef1c t\u1ebf, c\u00f3 nh\u1eefng tr\u01b0\u1eddng h\u1ee3p kh\u00f4ng theo l\u00fd thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc v\u00e0 th\u1eadm ch\u00ed \u0111\u00f4i khi n\u00f3 c\u00f2n sai l\u1ec7ch so v\u1edbi l\u00fd thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc [1]. Ti\u1ebfp theo, ch\u00fang ta s\u1ebd xem x\u00e9t ba l\u00fd thuy\u1ebft n\u00e2ng cao \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n t\u1eeb l\u00fd thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc (B\u1ea3ng 3.1<\/em>).<\/p>\n

Nhi\u1ec7t \u0111\u1ed9ng h\u1ecdc ch\u1ecdn l\u1ecdc<\/h2>\n

Nhi\u1ec7t \u0111\u1ed9ng h\u1ecdc ch\u1ecdn l\u1ecdc<\/strong> (Thermal kinetic selectivity, TKS) l\u00e0 m\u1ed9t l\u00fd thuy\u1ebft \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u1ed9 d\u00e0i xung khi c\u00e1c m\u00f4 \u0111\u00edch l\u1edbn v\u00e0 nh\u1ecf c\u00f9ng t\u1ed3n t\u1ea1i [2].<\/p>\n

V\u00ec \u0111\u1ed9 d\u00e0i xung t\u1ef7 l\u1ec7 v\u1edbi b\u00ecnh ph\u01b0\u01a1ng \u0111\u01b0\u1eddng k\u00ednh, c\u00e1c m\u00f4 l\u1edbn s\u1ebd c\u00f3 TRT d\u00e0i h\u01a1n (T2) v\u00e0 c\u00e1c m\u00f4 nh\u1ecf s\u1ebd c\u00f3 TRT (T1) ng\u1eafn h\u01a1n (T1 <T2). N\u1ebfu \u0111\u1ed9 d\u00e0i xung (PD) n\u1eb1m gi\u1eefa TRT c\u1ee7a c\u00e1c m\u00f4 l\u1edbn v\u00e0 nh\u1ecf (T1 <PD <T2), c\u00e1c m\u00f4 l\u1edbn s\u1ebd b\u1ecb t\u1ed5n th\u01b0\u01a1ng v\u00ec c\u00e1c m\u00f4 l\u1edbn (PD <T2) l\u00e0 TRT> PD. V\u1ea5n \u0111\u1ec1 l\u00e0 v\u1edbi c\u00e1c m\u00f4 nh\u1ecf. Tr\u01b0\u1eddng h\u1ee3p c\u00e1c m\u00f4 nh\u1ecf (T1 <PD),<\/p>\n

B\u1ea3ng 3.1 <\/strong>L\u00fd thuy\u1ebft n\u00e2ng cao v\u1ec1 qu\u00e1 tr\u00ecnh quang nhi\u1ec7t ch\u1ecdn l\u1ecdc\u00a0\u00a0\u00a0 <\/u><\/p>\n\n\n\n\n\n
1<\/td>\nNhi\u1ec7t \u0111\u1ed9ng h\u1ecdc ch\u1ecdn l\u1ecdc<\/td>\n<\/tr>\n
2<\/td>\nL\u00fd thuy\u1ebft m\u1edf r\u1ed9ng v\u1ec1 qu\u00e1 tr\u00ecnh quang nhi\u1ec7t ch\u1ecdn l\u1ecdc<\/td>\n<\/tr>\n
3<\/td>\nQuang nhi\u1ec7t ch\u1ecdn l\u1ecdc d\u01b0\u1edbi t\u1ebf b\u00e0o<\/u><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

TRT <PD, theo l\u00fd thuy\u1ebft v\u1ec1 quang nhi\u1ec7t ch\u1ecdn l\u1ecdc, c\u00e1c m\u00f4 xung quanh s\u1ebd b\u1ecb t\u1ed5n th\u01b0\u01a1ng v\u00e0 c\u00f3 t\u00e1c d\u1ee5ng ph\u1ee5. Tuy nhi\u00ean, trong th\u1ef1c t\u1ebf, t\u00e1c d\u1ee5ng ph\u1ee5 kh\u00f4ng x\u1ea3y ra; \u0111\u00fang h\u01a1n, c\u00e1c m\u00f4 nh\u1ecf \u0111\u01b0\u1ee3c b\u1ea3o t\u1ed3n m\u00e0 kh\u00f4ng b\u1ecb b\u1ea5t k\u1ef3 t\u00e1c \u0111\u1ed9ng n\u00e0o (H\u00ecnh 3.1<\/em>).<\/p>\n

Khi TRT <PD, n\u1ebfu \u0111\u1ed9 d\u00e0i xung \u0111\u1ee7 d\u00e0i, nhi\u1ec7t \u0111\u1ed9 c\u1ee7a c\u00e1c m\u00f4 nh\u1ecf kh\u00f4ng t\u0103ng l\u00ean n\u1eefa m\u00e0 h\u1ea1 nhi\u1ec7t trong qu\u00e1 tr\u00ecnh chi\u1ebfu x\u1ea1. T\u1ea1i sao hi\u1ec7n t\u01b0\u1ee3ng l\u1ea1i sai l\u1ec7ch v\u1edbi thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc? C\u00f3 ba c\u00e1ch \u0111\u1ec3 m\u1ea5t nhi\u1ec7t trong c\u00e1c m\u00f4: d\u1eabn nhi\u1ec7t, \u0111\u1ed1i l\u01b0u nhi\u1ec7t do d\u00f2ng m\u00e1u g\u00e2y ra v\u00e0 b\u1ee9c x\u1ea1 nhi\u1ec7t [3].<\/p>\n

\"Hai
Hai m\u1ea1ch m\u00e1u tr\u00ean da<\/figcaption><\/figure>\n

H\u00ecnh 3.1 <\/strong>Hai m\u1ea1ch m\u00e1u tr\u00ean da (1 v\u00e0 2), T1 v\u00e0 T2: th\u1eddi gian gi\u00e3n nhi\u1ec7t (TRT) t\u01b0\u01a1ng \u1ee9ng l\u00e0 1 v\u00e0 2 \u0110\u1ed9 d\u00e0i xung PD.<\/p>\n

D\u1eabn nhi\u1ec7t, s\u1ef1 truy\u1ec1n nhi\u1ec7t ra m\u00f4i tr\u01b0\u1eddng xung quanh, l\u00e0 ph\u01b0\u01a1ng ph\u00e1p t\u1ea3n nhi\u1ec7t ch\u00ednh. Tuy nhi\u00ean, n\u1ebfu \u0111\u1ed9 d\u00e0i xung \u0111\u1ee7 d\u00e0i, m\u00f4 nh\u1ecf s\u1ebd ngu\u1ed9i \u0111i do hai hi\u1ec7n t\u01b0\u1ee3ng sau (\u0111\u1ed1i l\u01b0u nhi\u1ec7t v\u00e0 b\u1ee9c x\u1ea1 nhi\u1ec7t). N\u00f3 gi\u1ed1ng nh\u01b0 l\u00e0 n\u01b0\u1edbc \u0111\u01b0\u1ee3c \u0111\u1ed5 t\u1eeb t\u1eeb xu\u1ed1ng m\u1ed9t c\u00e1i x\u00f4 c\u00f3 l\u1ed7. V\u00ed d\u1ee5, trong qu\u00e1 tr\u00ecnh \u0111i\u1ec1u tr\u1ecb c\u00e1c m\u00f4 l\u1edbn nh\u01b0 trong li\u1ec7u ph\u00e1p m\u1ea1ch m\u00e1u, c\u00e1c m\u00f4 nh\u1ecf nh\u01b0 melanosome cho th\u1ea5y kh\u00f4ng s\u1ef1 thay \u0111\u1ed5i. Ngo\u00e0i ra, trong qu\u00e1 tr\u00ecnh tri\u1ec7t l\u00f4ng b\u1eb1ng laser, ngay c\u1ea3 khi kh\u00f4ng l\u00e0m l\u1ea1nh bi\u1ec3u b\u00ec, \u0111\u1ed9 d\u00e0i xung d\u00e0i h\u01a1n TRT c\u1ee7a bi\u1ec3u b\u00ec (1\u201310 ms) ch\u1eb3ng h\u1ea1n nh\u01b0 30 ms kh\u00f4ng l\u00e0m t\u1ed5n th\u01b0\u01a1ng bi\u1ec3u b\u00ec. TKS c\u0169ng \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng cho nhi\u1ec1u t\u00ecnh hu\u1ed1ng kh\u00e1c nhau.<\/p>\n

V\u1eady TKS x\u1ea3y ra \u1edf kho\u1ea3ng \u0111\u1ed9 d\u00e0i xung n\u00e0o? T\u00f4i tin r\u1eb1ng TKS x\u1ea3y ra \u1edf xung d\u00e0i c\u00f3 \u0111\u1ed9 d\u00e0i kho\u1ea3ng mili gi\u00e2y. \u0110\u1eb7c bi\u1ec7t, t\u00f4i ngh\u0129 \u0111\u00f3 l\u00e0 hi\u1ec7n t\u01b0\u1ee3ng x\u1ea3y ra trong hi\u1ec7u \u1ee9ng quang nhi\u1ec7t d\u01b0\u1edbi 100\u00b0C.<\/p>\n

Ch\u00fang ta h\u00e3y ngh\u0129 l\u1ea1i v\u1ec1 \u0111\u1ed9 d\u00e0i xung trong c\u00e1c m\u00f4 l\u1edbn v\u00e0 nh\u1ecf. Trong tr\u01b0\u1eddng h\u1ee3p (T1 <PD <T2), c\u00e1c m\u00f4 l\u1edbn \u0111\u01b0\u1ee3c \u0111i\u1ec1u tr\u1ecb trong khi c\u00e1c m\u00f4 nh\u1ecf \u0111\u01b0\u1ee3c b\u1ea3o t\u1ed3n. M\u1eb7t kh\u00e1c, n\u1ebfu \u0111\u1ed9 d\u00e0i xung (PD) ng\u1eafn h\u01a1n TRT c\u1ee7a c\u00e1c m\u00f4 l\u1edbn v\u00e0 nh\u1ecf (PD <T1 <T2), c\u1ea3 m\u00f4 l\u1edbn v\u00e0 m\u00f4 nh\u1ecf s\u1ebd b\u1ecb t\u1ed5n th\u01b0\u01a1ng v\u00ec TRT> PD. Trong tr\u01b0\u1eddng h\u1ee3p n\u00e0y, nhi\u1ec7t \u0111\u1ed9 c\u1ee7a c\u00e1c m\u00f4 l\u1edbn c\u00f3 th\u1ec3 t\u0103ng \u0111\u1ebfn nhi\u1ec7t \u0111\u1ed9 qu\u00e1 cao, g\u00e2y ra c\u00e1c t\u00e1c d\u1ee5ng ph\u1ee5 [2]. Do \u0111\u00f3, (T1 <PD <T2) an to\u00e0n h\u01a1n (PD <T1 <T2). Sau \u0111\u00f3, l\u00e0m th\u1ebf n\u00e0o \u0111\u1ec3 ch\u00fang ta \u0111i\u1ec1u tr\u1ecb c\u00e1c m\u00f4 nh\u1ecf? Sau khi lo\u1ea1i b\u1ecf c\u00e1c m\u00f4 l\u1edbn \u0111\u1ea7u ti\u00ean v\u1edbi PD <T2, \u0111\u1ed9 d\u00e0i xung ph\u1ea3i gi\u1ea3m xu\u1ed1ng, \u00edt h\u01a1n TRT c\u1ee7a m\u00f4 nh\u1ecf (PD <T1), v\u00e0 c\u00e1c m\u00f4 nh\u1ecf c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c lo\u1ea1i b\u1ecf tu\u1ea7n t\u1ef1.<\/p>\n

K\u1ebft lu\u1eadn, trong kho\u1ea3ng \u0111\u1ed9 d\u00e0i xung d\u00e0i mili gi\u00e2y, s\u1ebd an to\u00e0n khi lo\u1ea1i b\u1ecf c\u00e1c m\u00f4 l\u1edbn tr\u01b0\u1edbc v\u00e0 c\u00e1c m\u00f4 nh\u1ecf sau \u0111\u00f3.<\/p>\n

L\u00fd thuy\u1ebft m\u1edf r\u1ed9ng v\u1ec1 qu\u00e1 tr\u00ecnh quang nhi\u1ec7t ch\u1ecdn l\u1ecdc<\/h3>\n

Ph\u1ea7n l\u1edbn nh\u1eefng g\u00ec \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 trong \u201cCh\u01b0\u01a1ng 1\u201d d\u1ef1a tr\u00ean gi\u1ea3 \u0111\u1ecbnh r\u1eb1ng m\u00f4 \u0111\u00edch v\u00e0 th\u1ec3 nhi\u1ec5m s\u1eafc tr\u00f9ng nhau. Tuy nhi\u00ean, tr\u00ean th\u1ef1c t\u1ebf, m\u00f4 \u0111\u00edch v\u00e0 th\u1ec3 nhi\u1ec5m s\u1eafc kh\u00f4ng tr\u00f9ng nhau [1]. M\u1ed9t v\u00ed d\u1ee5 l\u00e0 tri\u1ec7t l\u00f4ng b\u1eb1ng laser. C\u00e1c m\u00f4 \u0111\u00edch c\u1ee7a qu\u00e1 tr\u00ecnh tri\u1ec7t l\u00f4ng b\u1eb1ng laser l\u1ea7n l\u01b0\u1ee3t l\u00e0 t\u1ebf b\u00e0o m\u1ea7m l\u00f4ng v\u00e0 t\u1ebf b\u00e0o g\u1ed1c nang l\u00f4ng trong b\u1ea7u l\u00f4ng v\u00e0 ph\u00ecnh l\u00f4ng, v\u00e0 th\u1ec3 nhi\u1ec5m s\u1eafc t\u01b0\u01a1ng \u1ee9ng l\u00e0 ch\u1ea5t n\u1ec1n l\u00f4ng v\u00e0 th\u00e2n l\u00f4ng. T\u1ebf b\u00e0o m\u1ea7m l\u00f4ng v\u00e0 t\u1ebf b\u00e0o g\u1ed1c nang l\u00f4ng kh\u00f4ng c\u00f3 melanin.<\/p>\n

\"C\u1ea5u
C\u1ea5u tr\u00fac chung c\u1ee7a m\u00f4 \u0111\u00edch sinh h\u1ecdc v\u1edbi chia t\u00e1ch kh\u00f4ng gian gi\u1eefa m\u1ee5c ti\u00eau v\u00e0 b\u1ed9 ph\u1eadn h\u1ea5p th\u1ee5 (b\u1ed9 gia nhi\u1ec7t).<\/figcaption><\/figure>\n

H\u00ecnh 3.2 <\/strong>C\u1ea5u tr\u00fac chung c\u1ee7a m\u00f4 \u0111\u00edch sinh h\u1ecdc v\u1edbi chia t\u00e1ch kh\u00f4ng gian gi\u1eefa m\u1ee5c ti\u00eau v\u00e0 b\u1ed9 ph\u1eadn h\u1ea5p th\u1ee5 (b\u1ed9 gia nhi\u1ec7t).<\/p>\n

L\u00fd thuy\u1ebft m\u1edf r\u1ed9ng v\u1ec1 quang nhi\u1ec7t ch\u1ecdn l\u1ecdc (l\u00fd thuy\u1ebft m\u1edf r\u1ed9ng) l\u00e0 l\u00fd thuy\u1ebft l\u00e0m t\u1ed5n th\u01b0\u01a1ng c\u00e1c m\u00f4 \u0111\u00edch khi th\u1ec3 nhi\u1ec5m s\u1eafc v\u00e0 m\u00f4 \u0111\u00edch kh\u00f4ng tr\u00f9ng v\u1edbi nhau. Trong v\u00ed d\u1ee5 n\u00eau tr\u00ean v\u1ec1 tri\u1ec7t l\u00f4ng b\u1eb1ng laser, vi\u1ec7c chi\u1ebfu tia laser l\u00e0m t\u0103ng nhi\u1ec7t \u0111\u1ed9 c\u1ee7a s\u1ee3i l\u00f4ng, th\u1ec3 nhi\u1ec5m s\u1eafc, v\u00e0 nhi\u1ec7t \u0111\u1ed9 \u0111\u01b0\u1ee3c truy\u1ec1n \u0111\u1ebfn c\u00e1c t\u1ebf b\u00e0o g\u1ed1c nang l\u00f4ng th\u00f4ng qua s\u1ef1 khu\u1ebfch t\u00e1n nhi\u1ec7t v\u00e0 c\u00e1c t\u1ebf b\u00e0o b\u1ecb ph\u00e1 h\u1ee7y. L\u00fd thuy\u1ebft m\u1edf r\u1ed9ng l\u00e0 m\u1ed9t nguy\u00ean l\u00fd g\u00e2y t\u1ed5n th\u01b0\u01a1ng gi\u00e1n ti\u1ebfp m\u00f4 \u0111\u00edch th\u00f4ng qua s\u1ef1 khu\u1ebfch t\u00e1n nhi\u1ec7t trong m\u1ed9t th\u1ec3 nhi\u1ec5m s\u1eafc sinh nhi\u1ec7t (b\u1ed9 gia nhi\u1ec7t) (H\u00ecnh 3.2<\/em>). Do \u0111\u00f3, th\u1eddi gian gi\u00e3n nhi\u1ec7t (TRT) \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 trong qu\u00e1 tr\u00ecnh quang nhi\u1ec7t ch\u1ecdn l\u1ecdc kh\u00f4ng \u00e1p d\u1ee5ng cho l\u00fd thuy\u1ebft m\u1edf r\u1ed9ng, m\u00e0 thay v\u00e0o \u0111\u00f3 l\u00e0 th\u1eddi gian t\u1ed5n th\u01b0\u01a1ng nhi\u1ec7t (thermal damage time, TDT) \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng. TDT \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 th\u1eddi gian t\u1eeb v\u00f9ng th\u1ec3 nhi\u1ec5m s\u1eafc sinh nhi\u1ec7t (b\u1ed9 gia nhi\u1ec7t) \u0111\u1ebfn nhi\u1ec7t \u0111\u1ed9 m\u00e0 l\u1edbp ngo\u00e0i c\u00f9ng c\u1ee7a m\u00f4 \u0111\u00edch b\u1ecb h\u01b0 h\u1ea1i th\u00f4ng qua s\u1ef1 khu\u1ebfch t\u00e1n nhi\u1ec7t. Theo \u0111\u1ecbnh ngh\u0129a, TDT d\u00e0i h\u01a1n TRT (TDT> TRT) v\u00e0 \u0111\u1ed9 d\u00e0i xung ph\u1ea3i \u1edf gi\u1eefa TDT v\u00e0 TRT (TDT \u2265 PD> TRT).<\/p>\n

\u0110i\u1ec1u ki\u1ec7n \u0111\u1ec3 l\u00fd thuy\u1ebft m\u1edf r\u1ed9ng \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng l\u00e0 g\u00ec? M\u1ed9t t\u00e0i li\u1ec7u laser m\u00f4 t\u1ea3 r\u1eb1ng l\u00fd thuy\u1ebft m\u1edf r\u1ed9ng \u00e1p d\u1ee5ng cho \u201cc\u1ea5u tr\u00fac m\u1ee5c ti\u00eau h\u1ea5p th\u1ee5 kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t\u201d [3]. Ba th\u1ec3 nhi\u1ec5m s\u1eafc ch\u00ednh c\u1ee7a da l\u00e0 melanin, hemoglobin v\u00e0 n\u01b0\u1edbc. V\u00ec n\u01b0\u1edbc \u0111\u1ed3ng nh\u1ea5t \u1edf da, l\u00fd thuy\u1ebft m\u1edf r\u1ed9ng kh\u00f4ng \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng, nh\u01b0ng melanin v\u00e0 hemoglobin c\u00f3 th\u1ec3 kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t.<\/p>\n

\"M\u1ed9t
M\u1ed9t s\u01a1 \u0111\u1ed3 cho th\u1ea5y s\u1ef1 kh\u00e1c bi\u1ec7t trong vi\u1ec7c \u0111i\u1ec1u tr\u1ecb c\u00e1c t\u1ed5n th\u01b0\u01a1ng m\u1ea1ch m\u00e1u gi\u1eefa laser xung d\u00e0i (micro gi\u00e2y) v\u00e0 ng\u1eafn (nano gi\u00e2y).<\/figcaption><\/figure>\n

H\u00ecnh 3.3 <\/strong>M\u1ed9t s\u01a1 \u0111\u1ed3 cho th\u1ea5y s\u1ef1 kh\u00e1c bi\u1ec7t trong vi\u1ec7c \u0111i\u1ec1u tr\u1ecb c\u00e1c t\u1ed5n th\u01b0\u01a1ng m\u1ea1ch m\u00e1u gi\u1eefa laser xung d\u00e0i (micro gi\u00e2y) v\u00e0 ng\u1eafn (nano gi\u00e2y). C\u00e1c tia laser xung nano gi\u00e2y c\u00f3 th\u1ec3 l\u00e0m t\u1ed5n th\u01b0\u01a1ng c\u00e1c t\u1ebf b\u00e0o h\u1ed3ng c\u1ea7u, nh\u01b0ng kh\u00f4ng l\u00e0m t\u1ed5n th\u01b0\u01a1ng th\u00e0nh m\u1ea1ch, do \u0111\u00f3 kh\u00f4ng hi\u1ec7u qu\u1ea3 \u1edf c\u00e1c t\u1ed5n th\u01b0\u01a1ng m\u1ea1ch m\u00e1u. Tuy nhi\u00ean, c\u00e1c tia laser xung micro gi\u00e2y c\u00f3 th\u1ec3 l\u00e0m t\u1ed5n th\u01b0\u01a1ng kh\u00f4ng ch\u1ec9 c\u00e1c t\u1ebf b\u00e0o h\u1ed3ng c\u1ea7u m\u00e0 c\u00f2n c\u1ea3 c\u00e1c th\u00e0nh m\u1ea1ch.<\/p>\n

V\u00ed d\u1ee5, RBC trong m\u1ea1ch m\u00e1u l\u00e0 \u0111\u1ed3ng nh\u1ea5t, nh\u01b0ng m\u1ea1ch m\u00e1u \u0111\u01b0\u1ee3c c\u1ea5u t\u1ea1o b\u1edfi m\u00e1u v\u00e0 t\u1ebf b\u00e0o n\u1ed9i m\u00f4 m\u1ea1ch m\u00e1u, do \u0111\u00f3 to\u00e0n b\u1ed9 m\u1ea1ch m\u00e1u kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t. Chi\u1ebfu tia laser Q-switch 532 nm v\u1edbi \u0111\u1ed9 d\u00e0i xung 10 ns nh\u1eafm v\u00e0o RBC c\u00f3 TRT t\u1eeb 2\u20135 \u00b5s c\u00f3 th\u1ec3 l\u00e0m h\u1ecfng RBC nh\u01b0ng s\u1ebd kh\u00f4ng hi\u1ec7u qu\u1ea3 trong vi\u1ec7c \u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u (H\u00ecnh 3.3<\/em>). Do \u0111\u00f3, \u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u ch\u1ec9 c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c b\u1eb1ng c\u00e1ch chi\u1ebfu tia PDL v\u1edbi th\u1eddi gian xung t\u01b0\u01a1ng \u1ee9ng v\u1edbi TDT (ho\u1eb7c TRT c\u1ee7a to\u00e0n b\u1ed9 m\u1ea1ch m\u00e1u) trong \u0111\u00f3 nhi\u1ec7t \u0111\u01b0\u1ee3c truy\u1ec1n \u0111\u1ebfn th\u00e0nh m\u1ea1ch, kh\u00f4ng ph\u1ea3i v\u1edbi \u0111\u1ed9 d\u00e0i xung t\u01b0\u01a1ng \u1ee9ng v\u1edbi th\u1ec3 nhi\u1ec5m s\u1eafc (hemoglobin v\u00e0 RBC). Trong tr\u01b0\u1eddng h\u1ee3p c\u00e1c m\u1ea1ch c\u00f3 TRT t\u1eeb 1,2\u20134,8 ms, PDL 585 nm 450 \u00b5s t\u01b0\u01a1ng \u1ee9ng v\u1edbi micro gi\u00e2y thay v\u00ec \u0111\u01a1n v\u1ecb nano gi\u00e2y n\u00ean \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c hi\u1ec7u qu\u1ea3 mong mu\u1ed1n. C\u0169ng \u00e1p d\u1ee5ng t\u01b0\u01a1ng t\u1ef1 cho melanin. Melanin trong c\u00e1c melanosome c\u00f3 th\u1ec3 \u0111\u1ed3ng nh\u1ea5t, nh\u01b0ng c\u00e1c melanocyte ho\u1eb7c keratinocyte v\u1edbi melanosome, ho\u1eb7c l\u1edbp \u0111\u00e1y n\u01a1i c\u00e1c t\u1ebf b\u00e0o s\u1eebng n\u1eb1m kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t.<\/p>\n

V\u00ec v\u1eady, l\u00fd thuy\u1ebft m\u1edf r\u1ed9ng \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng \u0111\u1ec3 tri\u1ec7t l\u00f4ng b\u1eb1ng laser, \u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u v\u00e0 \u0111i\u1ec1u tr\u1ecb s\u1eafc t\u1ed1 b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng tia laser xung d\u00e0i.<\/p>\n

Quang nhi\u1ec7t ch\u1ecdn l\u1ecdc d\u01b0\u1edbi t\u1ebf b\u00e0o<\/h3>\n

Quang nhi\u1ec7t ch\u1ecdn l\u1ecdc d\u01b0\u1edbi t\u1ebf b\u00e0o l\u00e0 m\u1ed9t l\u00fd thuy\u1ebft \u0111\u01b0\u1ee3c bi\u1ebft \u0111\u1ebfn b\u1eb1ng c\u00e1ch nghi\u00ean c\u1ee9u m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 “laser<\/p>\n

toning”, m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong ph\u00f2ng kh\u00e1m t\u01b0. Tr\u01b0\u1edbc \u0111\u00e2y, laser b\u1ecb ch\u1ed1ng ch\u1ec9 \u0111\u1ecbnh trong \u0111i\u1ec1u tr\u1ecb n\u00e1m da v\u00ec ch\u00fang l\u00e0m tr\u1ea7m tr\u1ecdng th\u00eam t\u00ecnh tr\u1ea1ng n\u00e1m 6]. Tuy nhi\u00ean, sau khi s\u1eed d\u1ee5ng \u201claser toning\u201d \u0111\u1ec3 \u0111i\u1ec1u tr\u1ecb n\u00e1m t\u1ea1i ph\u00f2ng kh\u00e1m t\u01b0 \u1edf \u0110\u00f4ng \u00c1, \u0111\u00e3 c\u00f3 nh\u1eefng nghi\u00ean c\u1ee9u t\u00edch c\u1ef1c v\u1ec1 \u201claser toning\u201d.<\/p>\n

\u0110\u1ec3 t\u00ecm hi\u1ec3u nguy\u00ean l\u00fd c\u1ee7a laser toning, Kim et al. \u0111\u00e3 chi\u1ebfu tia laser Q-switched Nd: YAG 1064 nm l\u00ean c\u00e1 ng\u1ef1a v\u1eb1n v\u00e0 quan s\u00e1t s\u1ef1 thay \u0111\u1ed5i qua k\u00ednh hi\u1ec3n vi v\u00e0 sinh thi\u1ebft [7]. H\u1ecd quan s\u00e1t th\u1ea5y nh\u1eefng thay \u0111\u1ed5i trong c\u00e1c melanosome b\u1eb1ng c\u00e1ch chi\u1ebfu x\u1ea1 v\u1edbi m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng t\u1eeb 0,3 \u0111\u1ebfn 0,9 J\/cm2<\/sup> v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 7 mm v\u00e0 \u0111\u1ed9 d\u00e0i xung 5\u20137 ns. C\u00e1c melanosome b\u1ecb ph\u00e1 v\u1ee1 ngay c\u1ea3 \u1edf 0,3 J\/cm2<\/sup>, nh\u01b0ng m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ea7n \u00edt nh\u1ea5t 0,4 J\/cm2<\/sup> \u0111\u1ec3 th\u1ea5y r\u00f5 r\u00e0ng s\u1ef1 ph\u00e1 v\u1ee1 c\u1ee7a c\u00e1c melanosome (H\u00ecnh 3.4<\/em>).<\/p>\n

H\u00ecnh 3.5 <\/em>cho th\u1ea5y k\u1ebft qu\u1ea3 nhu\u1ed9m; m\u00e0u xanh c\u00f3 ngh\u0129a l\u00e0 nh\u00e2n b\u00ecnh th\u01b0\u1eddng v\u00e0 m\u00e0u \u0111\u1ecf c\u00f3 ngh\u0129a l\u00e0 t\u1ebf b\u00e0o apoptotic, t\u1ee9c l\u00e0 c\u00e1c t\u1ebf b\u00e0o s\u1ebd s\u1edbm ch\u1ebft. D\u01b0\u1edbi 0,4 J\/cm2<\/sup>, nh\u00e2n v\u00e0 t\u1ebf b\u00e0o \u0111\u1ec1u b\u00ecnh th\u01b0\u1eddng, nh\u01b0ng tr\u00ean 0,5 J \/ cm2<\/sup>, t\u1ebf b\u00e0o apoptotic \u0111\u01b0\u1ee3c ghi nh\u1eadn m\u1eb7c d\u00f9 nh\u00e2n b\u00ecnh th\u01b0\u1eddng.<\/p>\n

T\u1ed5ng h\u1ee3p l\u1ea1i, nh\u1eefng k\u1ebft qu\u1ea3 n\u00e0y cho th\u1ea5y \u1edf 0,4 J\/cm2<\/sup>, ch\u1ec9 c\u00f3 c\u00e1c melanosome b\u1ecb ph\u00e1 v\u1ee1 v\u00e0 c\u00e1c t\u1ebf b\u00e0o kh\u00f4ng b\u1ecb t\u1ed5n th\u01b0\u01a1ng. N\u00f3i c\u00e1ch kh\u00e1c, c\u00f3 m\u1ed9t \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 c\u00f3 th\u1ec3 ph\u00e1 v\u1ee1 c\u00e1c melanosome m\u00e0 kh\u00f4ng l\u00e0m t\u1ed5n th\u01b0\u01a1ng c\u00e1c t\u1ebf b\u00e0o\u201d.<\/p>\n

\"Nh\u1eefng
Nh\u1eefng thay \u0111\u1ed5i \u1edf c\u00e1c melanosome trong t\u1ebf b\u00e0o melanophore trong s\u1ecdc \u0111en c\u1ee7a c\u00e1 ng\u1ef1a v\u1eb1n sau 5 ng\u00e0y chi\u1ebfu laser Q-Switched Nd: YAG.<\/figcaption><\/figure>\n

H\u00ecnh 3.4 <\/strong>Nh\u1eefng thay \u0111\u1ed5i \u1edf c\u00e1c melanosome trong t\u1ebf b\u00e0o melanophore trong s\u1ecdc \u0111en c\u1ee7a c\u00e1 ng\u1ef1a v\u1eb1n sau 5 ng\u00e0y chi\u1ebfu laser Q-Switched Nd: YAG. \u1ede m\u1ee9c n\u0103ng l\u01b0\u1ee3ng 0,4 v\u00e0 0,9 J\/cm2<\/sup>, h\u1ea7u h\u1ebft c\u00e1c melanosome trong v\u00f9ng chi\u1ebfu \u0111\u1ec1u bi\u1ebfn m\u1ea5t v\u00e0o ng\u00e0y th\u1ee9 5 v\u00e0 v\u00f9ng \u0111\u01b0\u1ee3c \u0111i\u1ec1u tr\u1ecb kh\u00f4ng c\u00f3 s\u1eafc t\u1ed1. Ng\u01b0\u1ee3c l\u1ea1i, m\u1ed9t s\u1ed1 \u0111\u1ed1m s\u1eafc t\u1ed1 v\u1eabn c\u00f2n \u1edf m\u1ee9c n\u0103ng l\u01b0\u1ee3ng 0,3 J\/cm2<\/sup>.<\/p>\n

V\u00ed d\u1ee5, laser toning trong \u0111i\u1ec1u tr\u1ecb n\u00e1m kh\u00f4ng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn t\u1ebf b\u00e0o h\u1eafc t\u1ed1 hay t\u1ebf b\u00e0o s\u1eebng v\u00e0 kh\u00f4ng g\u00e2y t\u00e1c d\u1ee5ng ph\u1ee5 v\u00e0 n\u00f3 c\u00f3 hi\u1ec7u qu\u1ea3 trong \u0111i\u1ec1u tr\u1ecb n\u00e1m b\u1eb1ng c\u00e1ch ch\u1ec9 lo\u1ea1i b\u1ecf c\u00e1c melanosome c\u00f3 trong t\u1ebf b\u00e0o h\u1eafc t\u1ed1 v\u00e0 t\u1ebf b\u00e0o s\u1eebng.<\/p>\n

Sau 2 th\u00e1ng, t\u1ea5t c\u1ea3 c\u00e1c melanosome \u0111\u1ec1u h\u1ed3i ph\u1ee5c b\u1ea5t k\u1ec3 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng.<\/p>\n

L\u00fd thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc d\u01b0\u1edbi t\u1ebf b\u00e0o ban \u0111\u1ea7u t\u01b0\u01a1ng \u1ee9ng v\u1edbi l\u00fd thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc v\u00ec TRT c\u1ee7a c\u00e1c melanosome l\u00e0 250\u20131000 ns, v\u00e0 \u0111\u1ed9 d\u00e0i xung c\u1ee7a laser Q- Switch Nd: YAG l\u00e0 <10 ns, l\u00e0 c\u00f9ng \u0111\u01a1n v\u1ecb nano gi\u00e2y. Tuy nhi\u00ean, tr\u01b0\u1edbc \u0111\u00e2y, b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng hi\u1ec7u \u1ee9ng quang c\u01a1 c\u1ee7a laser Q- switched, vi\u1ec7c \u0111i\u1ec1u tr\u1ecb ph\u00e1 v\u1ee1 t\u1ebf b\u00e0o (TRT t\u1ebf b\u00e0o h\u1eafc t\u1ed1 l\u00e0 1\u201330 \u00b5s) \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 l\u00fd thuy\u1ebft v\u1ec1 quang nhi\u1ec7t c\u00f3 ch\u1ecdn l\u1ecdc. Do \u0111\u00f3, \u201cl\u00fd thuy\u1ebft ch\u1ec9 ph\u00e1 v\u1ee1 c\u00e1c melanosome m\u00e0 kh\u00f4ng l\u00e0m t\u1ed5n th\u01b0\u01a1ng t\u1ebf b\u00e0o\u201d ch\u1ec9 \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 \u201cl\u00fd thuy\u1ebft v\u1ec1 qu\u00e1 tr\u00ecnh quang nhi\u1ec7t ch\u1ecdn l\u1ecdc d\u01b0\u1edbi t\u1ebf b\u00e0o\u201d.<\/p>\n

Ch\u00fang ta h\u00e3y ngh\u0129 v\u1ec1 ph\u01b0\u01a1ng ph\u00e1p chi\u1ebfu tia nhi\u1ec1u l\u1ea7n, m\u1ed9t trong nh\u1eefng th\u00f4ng s\u1ed1 c\u1ee7a laser. “Laser toning” th\u01b0\u1eddng \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n b\u1eb1ng c\u00e1ch chi\u1ebfu h\u01a1n 1000 tia v\u00e0o m\u1eb7t \u1edf t\u1ea7n s\u1ed1 10 Hz. T\u1ea1i sao l\u1ea1i chi\u1ebfu r\u1ea5t nhi\u1ec1u tia \u1edf t\u1ea7n s\u1ed1 10 Hz? M\u1eb7c d\u00f9 kh\u00f4ng \u0111\u01b0\u1ee3c gi\u1edbi thi\u1ec7u trong b\u00e0i n\u00e0y, nh\u01b0ng poster c\u1ee7a Gi\u00e1o s\u01b0 Ilhwan Kim t\u1ea1i h\u1ed9i ngh\u1ecb l\u1ea7n th\u1ee9 60 c\u1ee7a hi\u1ec7p h\u1ed9i da li\u1ec5u H\u00e0n Qu\u1ed1c v\u00e0o n\u0103m 2008 \u0111\u1ec1 xu\u1ea5t chi\u1ebfu x\u1ea1 t\u1eebng tia (m\u1ed9t xung) [8]. Ngo\u00e0i ra, n\u1ebfu c\u00f3 “m\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 c\u00f3 th\u1ec3 ph\u00e1 v\u1ee1 c\u00e1c melanosome m\u00e0 kh\u00f4ng l\u00e0m t\u1ed5n h\u1ea1i c\u00e1c t\u1ebf b\u00e0o”, th\u00ec li\u1ec7u m\u1ed9t tia c\u00f3 \u0111\u1ee7 kh\u00f4ng? V\u00ec v\u1eady, t\u00f4i th\u1ef1c hi\u1ec7n c\u00e1i g\u1ecdi l\u00e0 one shot toning n\u01a1i n\u00e1m \u0111\u01b0\u1ee3c b\u1eafn t\u1eebng tia m\u1ed9t.<\/p>\n

Th\u1ef1c ch\u1ea5t c\u1ee7a thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc d\u01b0\u1edbi t\u1ebf b\u00e0o l\u00e0 g\u00ec? C\u00f3 m\u1ed9t \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 c\u00f3 th\u1ec3 ph\u00e1 v\u1ee1 c\u00e1c melanosome m\u00e0 kh\u00f4ng l\u00e0m t\u1ed5n h\u1ea1i c\u00e1c t\u1ebf b\u00e0o\u201d. N\u00f3i c\u00e1ch kh\u00e1c, c\u00f3 m\u1ed9t kh\u00e1i ni\u1ec7m v\u1ec1 m\u1ed9t c\u1eeda s\u1ed5 tr\u1ecb li\u1ec7u. Kh\u00e1i ni\u1ec7m l\u00e0 n\u00f3 kh\u00f4ng hi\u1ec7u qu\u1ea3 \u1edf n\u0103ng l\u01b0\u1ee3ng th\u1ea5p v\u00e0 c\u00f3 t\u00e1c d\u1ee5ng ph\u1ee5 \u1edf n\u0103ng l\u01b0\u1ee3ng cao v\u00e0 c\u00f3 \u0111\u1ee7 n\u0103ng l\u01b0\u1ee3ng s\u1ebd hi\u1ec7u qu\u1ea3 m\u00e0 kh\u00f4ng c\u00f3 t\u00e1c d\u1ee5ng ph\u1ee5.<\/p>\n

N\u1ebfu ch\u00fang ta \u0111i xu\u1ed1ng m\u1ed9t b\u01b0\u1edbc n\u1eefa so v\u1edbi kh\u00e1i ni\u1ec7m n\u00e0y, s\u1ebd kh\u00f4ng c\u00f3 “m\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 l\u00e0m t\u1ed5n th\u01b0\u01a1ng t\u1ebf b\u00e0o m\u00e0 kh\u00f4ng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn c\u00e1c t\u1ebf b\u00e0o xung quanh?” V\u00ec v\u1eady, \u0111\u1ed1i v\u1edbi c\u00e1c ph\u01b0\u01a1ng ph\u00e1p \u0111i\u1ec1u tr\u1ecb \u0111\u1ed1m n\u00e2u ho\u1eb7c PIH m\u00e0 kh\u00f4ng b\u1ecb vi\u00eam, t\u00f4i s\u1eed d\u1ee5ng n\u0103ng l\u01b0\u1ee3ng cao h\u01a1n cho one shot toning. C\u0169ng s\u1ebd c\u00f3 m\u1ed9t \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng ph\u00e1 v\u1ee1 kh\u00f4ng ch\u1ec9 c\u00e1c t\u1ebf b\u00e0o m\u00e0 c\u00f2n c\u00e1c m\u1ea1ch m\u00e1u xung quanh\u201d. \u0110\u00f3 l\u00e0 l\u00fd do t\u1ea1i sao ch\u1ea5m xu\u1ea5t huy\u1ebft x\u1ea3y ra trong qu\u00e1 tr\u00ecnh \u0111i\u1ec1u tr\u1ecb h\u00ecnh x\u0103m v\u00e0 ABNOM.<\/p>\n

\"TUNEL
TUNEL v\u00e0 nhu\u1ed9m 4\u2032,6-diamidino-2- phenylindole tr\u00ean da c\u00e1 ng\u1ef1a v\u1eb1n 1 ng\u00e0y sau khi chi\u1ebfu x\u1ea1 tia laser Q-Switched Nd: YAG 1064-nm.<\/figcaption><\/figure>\n

H\u00ecnh 3.5 <\/strong>TUNEL v\u00e0 nhu\u1ed9m 4\u2032,6-diamidino-2- phenylindole tr\u00ean da c\u00e1 ng\u1ef1a v\u1eb1n 1 ng\u00e0y sau khi chi\u1ebfu x\u1ea1 tia laser Q-Switched Nd: YAG 1064-nm.<\/p>\n

Ph\u01b0\u01a1ng ph\u00e1p nhu\u1ed9m 4 \u2032, 6- Diamidino-2-phenylindole (xanh lam) cho th\u1ea5y kh\u00f4ng c\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 s\u1ef1 ph\u00e2n b\u1ed1 v\u00e0 s\u1ed1 l\u01b0\u1ee3ng nh\u00e2n b\u00ecnh th\u01b0\u1eddng trong c\u00e1c m\u1eabu b\u1ecb chi\u1ebfu tia laser v\u1edbi c\u00e1c n\u0103ng l\u01b0\u1ee3ng kh\u00e1c nhau. Ng\u01b0\u1ee3c l\u1ea1i, nhu\u1ed9m TUNEL (\u0111\u1ecf) cho th\u1ea5y qu\u00e1 tr\u00ecnh apoptosis x\u1ea3y ra sau khi chi\u1ebfu tia laser v\u00e0 v\u1edbi s\u1ef1 ph\u1ee5 thu\u1ed9c r\u00f5 r\u00e0ng v\u00e0o n\u0103ng l\u01b0\u1ee3ng chi\u1ebfu tia laser. \u1ede m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng 0,5 J\/cm2<\/sup>, c\u00e1c t\u1ebf b\u00e0o apoptotic \u0111\u01b0\u1ee3c gi\u1edbi h\u1ea1n \u1edf ph\u1ea7n tr\u00ean c\u1ee7a bi\u1ec3u b\u00ec. \u1ede m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng 0,7 v\u00e0 0,9 J \/ cm2<\/sup>, qu\u00e1 tr\u00ecnh apoptosis lan r\u1ed9ng trong to\u00e0n b\u1ed9 l\u1edbp b\u00ec v\u00e0 l\u1edbp c\u01a1.<\/p>\n

V\u1eady, m\u1ee9c n\u00e0o l\u00e0 n\u0103ng l\u01b0\u1ee3ng ti\u00eau chu\u1ea9n cho \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 c\u00f3 th\u1ec3 ph\u00e1 v\u1ee1 c\u00e1c melanosome m\u00e0 kh\u00f4ng l\u00e0m t\u1ed5n h\u1ea1i t\u1ebf b\u00e0o\u201d, \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 l\u00e0m t\u1ed5n th\u01b0\u01a1ng t\u1ebf b\u00e0o m\u00e0 kh\u00f4ng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn c\u00e1c t\u1ebf b\u00e0o xung quanh\u201d v\u00e0 \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng kh\u00f4ng ch\u1ec9 ph\u00e1 v\u1ee1 t\u1ebf b\u00e0o m\u00e0 c\u00f2n c\u1ea3 c\u00e1c m\u1ea1ch m\u00e1u xung quanh \u201d. Sau khi xem x\u00e9t c\u00e1c m\u1ee9c n\u0103ng l\u01b0\u1ee3ng cho c\u00e1c t\u1ed5n th\u01b0\u01a1ng s\u1eafc t\u1ed1 trong c\u00e1c t\u00e0i li\u1ec7u kh\u00e1c nhau, t\u00f4i k\u1ebft lu\u1eadn r\u1eb1ng:<\/p>\n

\u201cTrong laser Q-Switched Nd:YAG 1064 nm, m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng 4 J\/cm2<\/sup> v\u00e0 6 J\/cm2<\/sup> v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 4 mm s\u1ebd l\u00e0 n\u0103ng l\u01b0\u1ee3ng ti\u00eau chu\u1ea9n cho m\u1ed9t l\u1ea7n b\u1eafn.\u201d<\/p>\n

V\u00ec v\u1eady, t\u00f4i khuy\u1ebfn ngh\u1ecb r\u1eb1ng v\u1edbi m\u1ed9t one shot toning, laser ph\u1ea3i \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng d\u01b0\u1edbi 4 J\/cm2<\/sup> \u0111\u1ed1i v\u1edbi n\u00e1m, \u0111\u00e2y l\u00e0 \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 c\u00f3 th\u1ec3 ph\u00e1 v\u1ee1 c\u00e1c melanosome m\u00e0 kh\u00f4ng l\u00e0m t\u1ed5n th\u01b0\u01a1ng c\u00e1c t\u1ebf b\u00e0o\u201d. V\u00e0 \u0111\u1ed1i v\u1edbi \u0111i\u1ec1u tr\u1ecb \u0111\u1ed1m n\u00e2u ho\u1eb7c PIH kh\u00f4ng c\u00f3 vi\u00eam, n\u00ean s\u1eed d\u1ee5ng m\u1ee9c n\u0103ng l\u01b0\u1ee3ng t\u1eeb 4 \u0111\u1ebfn 6 J\/cm2<\/sup>, \u0111\u00e2y l\u00e0 \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 l\u00e0m t\u1ed5n th\u01b0\u01a1ng t\u1ebf b\u00e0o m\u00e0 kh\u00f4ng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn c\u00e1c t\u1ebf b\u00e0o xung quanh\u201d. V\u00e0 \u0111\u1ed1i v\u1edbi \u0111i\u1ec1u tr\u1ecb h\u00ecnh x\u0103m ho\u1eb7c nevi t\u1ebf b\u00e0o h\u1eafc t\u1ed1, m\u1ee9c n\u0103ng l\u01b0\u1ee3ng ph\u1ea3i tr\u00ean 6 J\/cm2<\/sup>, \u0111\u00e2y l\u00e0 \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng c\u00f3 th\u1ec3 ph\u00e1 v\u1ee1 kh\u00f4ng ch\u1ec9 c\u00e1c t\u1ebf b\u00e0o m\u00e0 c\u00f2n c\u00e1c m\u1ea1ch m\u00e1u xung quanh\u201d.<\/p>\n

T\u00ednh m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng cho melanosome<\/h3>\n

T\u00ednh to\u00e1n th\u1ef1c t\u1ebf \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 c\u00f3 th\u1ec3 ph\u00e1 v\u1ee1 c\u00e1c melanosome m\u00e0 kh\u00f4ng l\u00e0m t\u1ed5n h\u1ea1i c\u00e1c t\u1ebf b\u00e0o\u201d. M\u1ee9c nhi\u1ec7t \u0111\u1ed9 m\u00e0 t\u1ea1i \u0111\u00f3 c\u00e1c melanosome v\u1ee1 ra v\u00e0 xu\u1ea5t hi\u1ec7n hi\u1ec7u \u1ee9ng quang \u00e2m v\u1eabn ch\u01b0a \u0111\u01b0\u1ee3c bi\u1ebft, nh\u01b0ng m\u1ee9c nhi\u1ec7t \u0111\u1ed9 t\u1ea1i \u0111\u00f3 c\u00e1c melanosome \u0111\u00f4ng t\u1ee5 th\u00ec \u0111\u00e3 \u0111\u01b0\u1ee3c bi\u1ebft. B\u1edfi v\u00ec laser Q-Switch Nd: YAG 1064 nm t\u1ed3n t\u1ea1i kh\u00f4ng ch\u1ec9 trong v\u00f9ng nhi\u1ec7t gi\u1edbi h\u1ea1n m\u00e0 c\u00f2n \u1edf v\u00f9ng stress, t\u00f4i tin r\u1eb1ng melanosome b\u1ecb v\u1ee1 ngay c\u1ea3 \u1edf nhi\u1ec7t \u0111\u1ed9 m\u00e0 melanosome b\u1ecb \u0111\u00f4ng t\u1ee5 (xem \u201cCh\u01b0\u01a1ng 2\u201d).<\/p>\n

T\u00ednh m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ea7n thi\u1ebft \u0111\u1ec3 \u0111\u00f4ng t\u1ee5 melanosome d\u1ef1a tr\u00ean c\u00e1c t\u00e0i li\u1ec7u c\u1ee7a Anderson v\u00e0 c\u1ed9ng s\u1ef1. [9]. M\u1eb7c d\u00f9 nhi\u1ec7t \u0111\u1ed9 \u0111\u00f4ng t\u1ee5 kh\u00e1c nhau gi\u1eefa c\u00e1c t\u00e0i li\u1ec7u laser, c\u00e1c b\u00e0i b\u00e1o c\u1ee7a Anderson et al. xem nh\u01b0 75\u00b0C l\u00e0 nhi\u1ec7t \u0111\u1ed9 t\u1ea1i \u0111\u00f3 c\u00e1c melanosome \u0111\u00f4ng t\u1ee5 v\u1edbi nhi\u1ec7t \u0111\u1ed9 da l\u00e0 35\u00b0C.<\/p>\n

D0= \u03c1S\u0394T\/f\u03b1,\u03b1d<1<\/em><\/i><\/p>\n

D<\/em>0 <\/em>\u2014 li\u1ec1u chi\u1ebfu x\u1ea1 v\u1edbi laser (J\/cm2<\/sup>)<\/p>\n

\u03c1 <\/em>\u2014 m\u1eadt \u0111\u1ed9 (\u2252 1,1 g \/ cm3<\/sup>)<\/p>\n

S <\/em>– nhi\u1ec7t dung ri\u00eang (\u2252 4,2 J\/g\u00b0C)<\/p>\n

\u0394T <\/em>– s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9<\/p>\n

f <\/em>– h\u1ec7 s\u1ed1 gi\u1ea3m d\u1ea7n<\/p>\n

\u03b1 <\/em>– h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5<\/p>\n

d <\/em>– k\u00edch th\u01b0\u1edbc trung b\u00ecnh m\u1ee5c ti\u00eau.<\/p>\n

Trong tr\u01b0\u1eddng h\u1ee3p b\u01b0\u1edbc s\u00f3ng 1064 nm, \u0111\u1ed9 xuy\u00ean s\u00e2u quang h\u1ecdc d\u00e0i h\u01a1n k\u00edch th\u01b0\u1edbc c\u1ee7a melanosome, t\u01b0\u01a1ng \u1ee9ng v\u1edbi \u03b1d <\/em><1, c\u00f3: 1.70 x 1012<\/sup> nm-3.48<\/sup> (cm-1<\/sup>) cho da<\/p>\n

H\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 c\u0169ng kh\u00e1c nhau gi\u1eefa c\u00e1c t\u00e0i li\u1ec7u laser, nh\u01b0ng n\u1ebfu ch\u00fang ta thay th\u1ebf 1064 nm trong c\u00f4ng th\u1ee9c c\u1ee7a h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 trong m\u1ed9t t\u00e0i li\u1ec7u, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 l\u00e0 49,7 cm-1<\/sup> [10]. Cu\u1ed1i c\u00f9ng, kh\u00f4ng c\u00f3 t\u00e0i li\u1ec7u ho\u1eb7c b\u00e0i b\u00e1o n\u00e0o cho th\u1ea5y c\u00e1c gi\u00e1 tr\u1ecb h\u1ec7 s\u1ed1 gi\u1ea3m d\u1ea7n, nh\u01b0ng h\u00e3y thay th\u1ebf 0,9 v\u00ec h\u1ec7 s\u1ed1 gi\u1ea3m d\u1ea7n l\u00e0 0,5 \u1edf 351 nm v\u00e0 0,8 \u1edf 700 nm.<\/p>\n

K\u1ebft qu\u1ea3 cho th\u1ea5y 4,1 J\/cm2<\/sup> \u1edf b\u01b0\u1edbc s\u00f3ng 1064 nm. N\u00f3i c\u00e1ch kh\u00e1c, c\u00e1c melanosome \u0111\u00f4ng t\u1ee5 \u1edf m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng 4,1 J\/cm2<\/sup> c\u1ee7a<\/p>\n

laser 1064 nm. \u0110i\u1ec1u n\u00e0y t\u01b0\u01a1ng t\u1ef1 nh\u01b0 \u201cm\u1ee9c n\u0103ng l\u01b0\u1ee3ng ch\u1ec9 c\u00f3 th\u1ec3 ph\u00e1 v\u1ee1 c\u00e1c melanosome m\u00e0 kh\u00f4ng l\u00e0m t\u1ed5n h\u1ea1i t\u1ebf b\u00e0o\u201d, l\u00e0 m\u1ee9c n\u0103ng l\u01b0\u1ee3ng d\u01b0\u1edbi 4 J\/cm2<\/sup>, nh\u01b0 \u0111\u00e3 \u0111\u1ec1 c\u1eadp tr\u01b0\u1edbc \u0111\u00f3.<\/p>\n

\u0110\u1ec3 tham kh\u1ea3o, khi h\u1ec7 s\u1ed1 gi\u1ea3m d\u1ea7n l\u00e0 0,65 \u1edf b\u01b0\u1edbc s\u00f3ng 532 nm, m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ea7n thi\u1ebft \u0111\u1ec3 \u0111\u00f4ng t\u1ee5 c\u00e1c melanosome l\u00e0 0,51 J\/cm2<\/sup>.<\/p>\n

L\u1ef1a ch\u1ecdn c\u00e1c th\u00f4ng s\u1ed1<\/h2>\n

S\u1ef1 kh\u00f3 kh\u0103n trong vi\u1ec7c x\u00e1c \u0111\u1ecbnh c\u00e1c th\u00f4ng s\u1ed1<\/h3>\n

\u00cdt nh\u1ea5t ba th\u00f4ng s\u1ed1 ph\u1ea3i \u0111\u01b0\u1ee3c l\u1ef1a ch\u1ecdn t\u01b0\u01a1ng \u1ee9ng \u0111\u1ec3 b\u1ed5 sung thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc [11]. Ba th\u00f4ng s\u1ed1 n\u00e0y th\u01b0\u1eddng \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u201cba th\u00f4ng s\u1ed1\u201d c\u1ee7a l\u00fd thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc: b\u01b0\u1edbc s\u00f3ng, \u0111\u1ed9 d\u00e0i xung v\u00e0 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng. \u0110\u1ea7u ti\u00ean, n\u00ean ch\u1ecdn b\u01b0\u1edbc s\u00f3ng \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5 nhi\u1ec1u b\u1edfi th\u1ec3 nhi\u1ec5m s\u1eafc h\u01a1n c\u00e1c m\u00f4 xung quanh. \u0110\u1ed9 s\u00e2u c\u1ee7a th\u1ec3 nhi\u1ec5m s\u1eafc c\u0169ng c\u1ea7n \u0111\u01b0\u1ee3c t\u00ednh \u0111\u1ebfn khi ch\u1ecdn b\u01b0\u1edbc s\u00f3ng. Th\u1ee9 hai, \u0111\u1ed9 d\u00e0i xung ph\u1ea3i nh\u1ecf h\u01a1n ho\u1eb7c b\u1eb1ng TRT c\u1ee7a m\u00f4 \u0111\u00edch \u0111\u1ec3 h\u1ea1n ch\u1ebf t\u1ed5n th\u01b0\u01a1ng nhi\u1ec7t cho c\u00e1c m\u00f4 xung quanh. Th\u1ee9 ba, m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng ph\u1ea3i g\u00e2y ra t\u1ed5n th\u01b0\u01a1ng nhi\u1ec7t \u0111\u1ee7 cho m\u00f4 \u0111\u00edch v\u00e0 ph\u00e1 h\u1ee7y n\u00f3. V\u00ec m\u1ed7i trong 3 th\u00f4ng s\u1ed1 n\u00e0y ph\u1ea3i \u0111\u01b0\u1ee3c l\u1ef1a ch\u1ecdn n\u00ean c\u00f3 r\u1ea5t nhi\u1ec1u tr\u01b0\u1eddng h\u1ee3p. V\u00ed d\u1ee5, n\u1ebfu c\u00f3 ba t\u00f9y ch\u1ecdn v\u1ec1 b\u01b0\u1edbc s\u00f3ng, \u0111\u1ed9 d\u00e0i xung v\u00e0 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng t\u01b0\u01a1ng \u1ee9ng, th\u00ec c\u00f3 27 tr\u01b0\u1eddng h\u1ee3p (3 \u00d7 3 \u00d7 3 = 27). V\u00ec b\u01b0\u1edbc s\u00f3ng \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh khi mua thi\u1ebft b\u1ecb laser, th\u1ef1c t\u1ebf c\u00f3 ch\u00edn tr\u01b0\u1eddng h\u1ee3p (1 \u00d7 3 \u00d7 3 = 9). Ch\u00edn tr\u01b0\u1eddng h\u1ee3p, d\u00f9 ch\u01b0a \u0111\u1ebfn 27, kh\u00f4ng ph\u1ea3i l\u00e0 l\u1ef1a ch\u1ecdn d\u1ec5 d\u00e0ng. V\u00ed d\u1ee5, gi\u1ea3 s\u1eed r\u1eb1ng c\u00f3 s\u1ed1 tr\u01b0\u1eddng h\u1ee3p t\u1eeb 1\u20139, trong \u0111\u00f3 1\u20134 kh\u00f4ng hi\u1ec7u qu\u1ea3, 5 c\u00f3 hi\u1ec7u qu\u1ea3, v\u00e0 t\u00e1c d\u1ee5ng ph\u1ee5 x\u1ea3y ra trong 6\u20139. X\u00e1c su\u1ea5t c\u00f3 hi\u1ec7u qu\u1ea3 m\u00e0 kh\u00f4ng c\u00f3 t\u00e1c d\u1ee5ng ph\u1ee5 l\u00e0 kho\u1ea3ng 10%. Do \u0111\u00f3, vi\u1ec7c x\u00e1c \u0111\u1ecbnh c\u00e1c th\u00f4ng s\u1ed1 c\u1ee7a tia laser kh\u00f4ng h\u1ec1 \u0111\u01a1n gi\u1ea3n.<\/p>\n

Hi\u1ec7u qu\u1ea3 vs An to\u00e0n?<\/h3>\n

B\u00e1c s\u0129 s\u1eed d\u1ee5ng laser ph\u1ea3i x\u00e1c \u0111\u1ecbnh ba ho\u1eb7c s\u00e1u th\u00f4ng s\u1ed1. Tuy nhi\u00ean, quy\u1ebft \u0111\u1ecbnh cu\u1ed1i c\u00f9ng l\u00e0 l\u1ef1a ch\u1ecdn hi\u1ec7u qu\u1ea3 ho\u1eb7c an to\u00e0n (m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng). Ch\u1ecdn hi\u1ec7u qu\u1ea3 l\u00e0m t\u0103ng kh\u1ea3 n\u0103ng x\u1ea3y ra t\u00e1c d\u1ee5ng ph\u1ee5 v\u00e0 ch\u1ecdn an to\u00e0n l\u00e0m t\u0103ng kh\u1ea3 n\u0103ng kh\u00f4ng c\u00f3 hi\u1ec7u qu\u1ea3. Ch\u00fang ta s\u1ebd ch\u1ecdn c\u00e1i n\u00e0o? Hi\u1ec7u qu\u1ea3 so v\u1edbi an to\u00e0n?<\/p>\n

M\u1ed9t s\u1ed1 ng\u01b0\u1eddi th\u00edch so s\u00e1nh vi\u1ec7c th\u1ef1c h\u00e0nh c\u00e1 nh\u00e2n v\u1edbi t\u1eadp v\u00f5 thu\u1eadt, v\u00e0 gi\u1ed1ng nh\u01b0 nh\u1eefng ng\u01b0\u1eddi m\u1edbi t\u1eadp v\u00e0 b\u1eadc th\u1ea7y v\u00f5 thu\u1eadt, s\u1ebd c\u00f3 nh\u1eefng ng\u01b0\u1eddi m\u1edbi h\u1ecdc v\u00e0 b\u1eadc th\u1ea7y trong c\u00e1c b\u00e1c s\u0129 s\u1eed d\u1ee5ng laser. S\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa ng\u01b0\u1eddi m\u1edbi v\u00e0 ng\u01b0\u1eddi th\u00e0nh th\u1ea1o trong b\u00e1c s\u0129 laser l\u00e0 g\u00ec? T\u00f4i ngh\u0129 n\u1ebfu c\u00e1c tia laser gi\u1ed1ng nhau, kh\u00f4ng c\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 hi\u1ec7u \u1ee9ng gi\u1eefa ng\u01b0\u1eddi m\u1edbi v\u00e0 ng\u01b0\u1eddi th\u00e0nh th\u1ea1o. B\u1edfi v\u00ec n\u1ebfu tia laser \u0111\u01b0\u1ee3c chi\u1ebfu v\u1edbi c\u00f4ng su\u1ea5t cao th\u00ec s\u1ebd cho hi\u1ec7u qu\u1ea3 \u1edf c\u1ea3 ng\u01b0\u1eddi m\u1edbi v\u00e0 ng\u01b0\u1eddi th\u00e0nh th\u1ea1o. Tuy nhi\u00ean, c\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 x\u00e1c su\u1ea5t x\u1ea3y ra c\u00e1c ph\u1ea3n \u1ee9ng ph\u1ee5 \u0111\u1ed1i v\u1edbi ng\u01b0\u1eddi m\u1edbi v\u00e0 ng\u01b0\u1eddi th\u00e0nh th\u1ea1o. T\u00f4i ngh\u0129 \u201cb\u00e1c s\u0129 laser b\u1eadc th\u1ea7y\u201d l\u00e0 ng\u01b0\u1eddi t\u1ea1o ra c\u00e1c hi\u1ec7u qu\u1ea3 t\u01b0\u01a1ng t\u1ef1 v\u1edbi t\u00e1c d\u1ee5ng ph\u1ee5 t\u1ed1i thi\u1ec3u.<\/p>\n

V\u00ec v\u1eady, t\u00f4i tin r\u1eb1ng \u0111\u1ec3 tr\u1edf th\u00e0nh m\u1ed9t \u201cb\u1eadc th\u1ea7y\u201d, s\u1ef1 an to\u00e0n ph\u1ea3i \u0111\u01b0\u1ee3c l\u1ef1a ch\u1ecdn h\u01a1n l\u00e0 hi\u1ec7u qu\u1ea3. T\u1ea5t nhi\u00ean, an to\u00e0n m\u00e0 kh\u00f4ng hi\u1ec7u qu\u1ea3 c\u0169ng l\u00e0 \u0111i\u1ec1u kh\u00f4ng mong mu\u1ed1n. Qua \u0111\u00e0o t\u1ea1o v\u00e0 kinh nghi\u1ec7m, c\u00e1c th\u00f4ng s\u1ed1 an to\u00e0n v\u00e0 hi\u1ec7u qu\u1ea3 s\u1ebd \u0111\u01b0\u1ee3c t\u00ecm th\u1ea5y.<\/p>\n

\u0110\u1ed9c gi\u1ea3 s\u1ebd c\u00f3 th\u1ec3 ch\u1ea1m t\u1edbi tr\u1ecdng t\u00e2m c\u1ee7a th\u1ee7 thu\u1eadt laser n\u1ebfu h\u1ecd ch\u00fa tr\u1ecdng nhi\u1ec1u h\u01a1n \u0111\u1ebfn t\u00ednh an to\u00e0n h\u01a1n l\u00e0 t\u00ednh hi\u1ec7u qu\u1ea3 khi \u0111\u1ecdc cu\u1ed1n s\u00e1ch n\u00e0y.<\/p>\n

B\u01b0\u1edbc s\u00f3ng<\/h2>\n

H\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5<\/h3>\n

Ph\u01b0\u01a1ng ph\u00e1p \u0111o h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 nh\u01b0 sau. \u00c1nh s\u00e1ng c\u00f3 b\u01b0\u1edbc s\u00f3ng \u0111\u01a1n s\u1eafc, nh\u01b0 laser, \u0111\u01b0\u1ee3c chi\u1ebfu x\u1ea1 v\u00e0 \u0111i qua m\u1ed9t kh\u1ed1i thu\u1ef7 tinh \u0111\u1ee5c c\u00f3 ch\u1ee9a th\u1ec3 nhi\u1ec5m s\u1eafc. \u00c1nh s\u00e1ng c\u00f2n l\u1ea1i \u0111\u01b0\u1ee3c \u0111o b\u1eb1ng m\u00e1y d\u00f2. T\u1ef7 s\u1ed1 gi\u1eefa c\u01b0\u1eddng \u0111\u1ed9 \u00e1nh s\u00e1ng (I0) tr\u01b0\u1edbc khi chi\u1ebfu x\u1ea1 v\u00e0o kh\u1ed1i thu\u1ef7 tinh m\u1ee5c ti\u00eau v\u00e0 c\u01b0\u1eddng \u0111\u1ed9 \u00e1nh s\u00e1ng c\u00f2n l\u1ea1i khi qua m\u1ee5c ti\u00eau (I) l\u00e0 t\u1ef7 l\u1ec7 h\u1ea5p th\u1ee5 (H\u00ecnh 3.6<\/em>) [13].<\/p>\n

\"M\u00f4
M\u00f4 h\u00ecnh Kubelka \u2013 Munk<\/figcaption><\/figure>\n

H\u00ecnh 3.6 <\/strong>M\u00f4 h\u00ecnh Kubelka \u2013 Munk \u0111\u1ec3 truy\u1ec1n b\u1ee9c x\u1ea1 trong m\u00f4i tr\u01b0\u1eddng h\u1ea5p th\u1ee5, \u0111\u1ee5c.<\/p>\n

T\u1ef7 l\u1ec7 h\u1ea5p th\u1ee5 n\u00e0y gi\u1ea3m theo h\u00e0m c\u1ee7a ch\u1ec9 s\u1ed1 t\u1ef1 nhi\u00ean (xem \u201cCh\u01b0\u01a1ng 1\u201d).<\/p>\n

T\u1ef7 l\u1ec7 h\u1ea5p th\u1ee5 bao g\u1ed3m \u0111\u1ed9 s\u00e2u m\u1ee5c ti\u00eau (chi\u1ec1u d\u00e0i L<\/em>) v\u00e0 c\u00e1c y\u1ebfu t\u1ed1 kh\u00e1c v\u1edbi \u0111\u1ed9 s\u00e2u m\u1ee5c ti\u00eau. C\u00e1c y\u1ebfu t\u1ed1 kh\u00e1c v\u1edbi \u0111\u1ed9 s\u00e2u m\u1ee5c ti\u00eau c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh l\u00e0 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 (\u00b5<\/em>a<\/em>). D\u1ef1a tr\u00ean c\u01b0\u1eddng \u0111\u1ed9 \u00e1nh s\u00e1ng trong \u0111\u00f3 \u00b5<\/em>aL <\/em>b\u1eb1ng 1.<\/p>\n

H\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 l\u00e0 (1\/chi\u1ec1u d\u00e0i) v\u00e0 \u0111\u01a1n v\u1ecb l\u00e0 cm\u2212<\/sup> 1<\/sup>. Do \u0111\u00f3, \u0111\u1ecbnh ngh\u0129a c\u1ee7a h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 kh\u1ea3 n\u0103ng ho\u1eb7c x\u00e1c su\u1ea5t c\u00e1c photon c\u1ee7a m\u1ed9t b\u01b0\u1edbc s\u00f3ng c\u1ee5 th\u1ec3 b\u1ecb h\u1ea5p th\u1ee5 tr\u00ean m\u1ed9t \u0111\u01a1n v\u1ecb chi\u1ec1u d\u00e0i [1].<\/p>\n

N\u1ebfu h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 = 1\/length \u0111\u01b0\u1ee3c hi\u1ec3u theo c\u00e1ch kh\u00e1c, th\u00ec c\u00f3 th\u1ec3 hi\u1ec3u l\u00e0 \u201cc\u00e1c photon xuy\u00ean s\u00e2u \u00edt \u1edf tia laser c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 cao v\u00e0 c\u00e1c photon xuy\u00ean s\u00e2u nhi\u1ec1u \u1edf tia laser c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 th\u1ea5p.\u201d C\u00e1c v\u00ed d\u1ee5 bao g\u1ed3m laser CO2 c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 n\u01b0\u1edbc cao v\u00e0 laser Nd: YAG c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 n\u01b0\u1edbc th\u1ea5p. Laser CO2 c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 cao s\u1ebd \u0111i v\u00e0o n\u00f4ng v\u00e0 l\u00e0m bay h\u01a1i l\u1edbp th\u01b0\u1ee3ng b\u00ec l\u00e0m bong da, nh\u01b0ng laser Nd:YAG c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 th\u1ea5p s\u1ebd truy\u1ec1n nhi\u1ec7t v\u00e0o s\u00e2u l\u1edbp b\u00ec n\u00ean c\u00f3 th\u1ec3 g\u00e2y b\u1ecfng s\u00e2u v\u1edbi n\u0103ng l\u01b0\u1ee3ng cao.<\/p>\n

H\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 \u0111\u01b0\u1ee3c bi\u1ebft l\u00e0 thay \u0111\u1ed5i b\u1edfi hai bi\u1ebfn s\u1ed1 [14]. \u0110\u1ea7u ti\u00ean, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 thay \u0111\u1ed5i t\u00f9y thu\u1ed9c v\u00e0o th\u1ec3 nhi\u1ec5m s\u1eafc. Th\u1ee9 hai, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 thay \u0111\u1ed5i t\u00f9y theo b\u01b0\u1edbc s\u00f3ng. Do \u0111\u00f3, m\u1ed9t \u0111\u01b0\u1eddng cong h\u1ea5p th\u1ee5 \u0111\u01b0\u1ee3c t\u1ea1o ra (H\u00ecnh 3.7<\/em>). V\u00ed d\u1ee5, laser ruby 694 nm \u0111\u01b0\u1ee3c ph\u00e1t hi\u1ec7n c\u00f3 kh\u1ea3 n\u0103ng \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5 cao trong melanin v\u00e0 h\u1ea5p th\u1ee5 th\u1ea5p trong hemoglobin v\u00e0 laser Nd:YAG 1064 nm \u0111\u01b0\u1ee3c ph\u00e1t hi\u1ec7n c\u00f3 \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5 th\u1ea5p trong melanin, hemoglobin v\u00e0 n\u01b0\u1edbc. K\u1ebft lu\u1eadn, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 ph\u1ee5 thu\u1ed9c v\u00e0o hai bi\u1ebfn s\u1ed1 l\u00e0 b\u01b0\u1edbc s\u00f3ng v\u00e0 th\u1ec3 nhi\u1ec5m s\u1eafc.<\/p>\n

Tuy nhi\u00ean, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 kh\u00f4ng ph\u1ea3i l\u00e0 h\u1eb1ng s\u1ed1 \u0111\u1ed1i v\u1edbi m\u1ed7i th\u1ec3 nhi\u1ec5m s\u1eafc. Ngay c\u1ea3 v\u1edbi c\u00f9ng m\u1ed9t th\u1ec3 nhi\u1ec5m s\u1eafc, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 ph\u1ee5 thu\u1ed9c v\u00e0o m\u1eadt \u0111\u1ed9 c\u1ee7a th\u1ec3 nhi\u1ec5m s\u1eafc [2].<\/p>\n

\"Ph\u1ed5
Ph\u1ed5 h\u1ea5p th\u1ee5<\/figcaption><\/figure>\n

H\u00ecnh 3.7 <\/strong>Ph\u1ed5 h\u1ea5p th\u1ee5. Ph\u1ed5 h\u1ea5p th\u1ee5 kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t c\u1ee7a th\u1ec3 nhi\u1ec5m s\u1eafc cho ph\u00e9p qu\u00e1 tr\u00ecnh quang nhi\u1ec7t c\u00f3 ch\u1ecdn l\u1ecdc ho\u1ea1t \u0111\u1ed9ng.<\/p>\n

Do \u0111\u00f3, ngay c\u1ea3 khi c\u00e1c th\u1ec3 nhi\u1ec5m s\u1eafc c\u00f3 c\u00f9ng h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 thay \u0111\u1ed5i t\u00f9y theo m\u1eadt \u0111\u1ed9. Th\u1ec3 nhi\u1ec5m s\u1eafc m\u00e0 ch\u00fang ta gi\u1ea3 \u0111\u1ecbnh l\u00e0 m\u1ee5c ti\u00eau l\u00e0 m\u1ee5c ti\u00eau \u0111\u01a1n l\u1ebb nh\u01b0ng th\u1ef1c t\u1ebf th\u1ec3 nhi\u1ec5m s\u1eafc l\u00e0 nh\u00f3m c\u00e1c m\u1ee5c ti\u00eau. V\u00ed d\u1ee5, khi \u0111i\u1ec1u tr\u1ecb s\u1eafc t\u1ed1, m\u1ee5c ti\u00eau \u0111\u01a1n l\u1ebb l\u00e0 melanosome, nh\u01b0ng m\u1eadt \u0111\u1ed9 melanosome kh\u00e1c nhau \u1edf m\u1ed7i t\u1ebf b\u00e0o h\u1eafc t\u1ed1 ch\u1ee9a melanosome, v\u00e0 m\u1eadt \u0111\u1ed9 t\u1ebf b\u00e0o h\u1eafc t\u1ed1 c\u0169ng kh\u00e1c nhau trong m\u1ed7i \u0111\u1ed1m n\u00e2u m\u00e0 c\u00e1c t\u1ebf b\u00e0o h\u1eafc t\u1ed1 t\u1eadp h\u1ee3p l\u1ea1i. Do \u0111\u00f3, m\u1eb7c d\u00f9 c\u00f3 c\u00f9ng c\u00e1c melanosome l\u00e0 c\u00e1c m\u1ee5c ti\u00eau, c\u00e1c \u0111\u1ed1m n\u00e2u s\u00e1ng m\u00e0u c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 th\u1ea5p, trong khi c\u00e1c \u0111\u1ed1m n\u00e2u s\u1eadm m\u00e0u c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 cao. \u0110\u00f3 l\u00e0 l\u00fd do t\u1ea1i sao ch\u00fang t\u00f4i bi\u1ebft theo kinh nghi\u1ec7m r\u1eb1ng ch\u00fang t\u00f4i n\u00ean chi\u1ebfu x\u1ea1 \u201cc\u00e1c t\u1ed5n th\u01b0\u01a1ng t\u1ed1i m\u00e0u y\u1ebfu v\u00e0 c\u00e1c t\u1ed5n th\u01b0\u01a1ng s\u00e1ng m\u00e0u m\u1ea1nh\u201d.<\/p>\n

T\u1eeb nh\u1eefng \u0111i\u1ec1u n\u00e0y, ch\u00fang ta c\u00f3 th\u1ec3 r\u00fat ra hai k\u1ebft lu\u1eadn:<\/p>\n

    \n
  1. C\u00e1c t\u1ed5n th\u01b0\u01a1ng kh\u00e1c nhau c\u00f3 m\u1eadt \u0111\u1ed9 kh\u00e1c nhau, do \u0111\u00f3 n\u0103ng l\u01b0\u1ee3ng ph\u1ea3i \u0111\u01b0\u1ee3c ki\u1ec3m so\u00e1t kh\u00e1c nhau. N\u00f3i c\u00e1ch kh\u00e1c, ch\u00fang ta n\u00ean chi\u1ebfu tia \u201cc\u00e1c t\u1ed5n th\u01b0\u01a1ng t\u1ed1i m\u00e0u y\u1ebfu v\u00e0 c\u00e1c t\u1ed5n th\u01b0\u01a1ng s\u00e1ng m\u00e0u m\u1ea1nh\u201d.<\/li>\n
  2. Kh\u00f4ng c\u00f3 th\u00f4ng s\u1ed1 tuy\u1ec7t \u0111\u1ed1i.<\/li>\n<\/ol>\n

    \u0110\u1ed9 s\u00e2u x\u00e2m nh\u1eadp quang h\u1ecdc<\/h3>\n

    Da c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c coi nh\u01b0 m\u1ed9t m\u00f4i tr\u01b0\u1eddng \u0111\u1ee5c \u0111\u01b0\u1ee3c t\u1ea1o th\u00e0nh t\u1eeb c\u00e1c v\u1eadt ch\u1ea5t nh\u1ecf nh\u01b0 m\u00e1u, melanin, bilirubin v\u00e0 collagen [1]. Khi c\u00e1c photon g\u1eb7p c\u00e1c v\u1eadt ch\u1ea5t n\u00e0y, hi\u1ec7n t\u01b0\u1ee3ng t\u00e1n x\u1ea1 x\u1ea3y ra do h\u00ecnh d\u1ea1ng ho\u1eb7c k\u00edch th\u01b0\u1edbc c\u1ee7a v\u1eadt ch\u1ea5t, \u0111\u1eb7c bi\u1ec7t l\u00e0 s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 chi\u1ebft su\u1ea5t. Tuy nhi\u00ean, \u1edf b\u01b0\u1edbc s\u00f3ng tr\u00ean 2500 nm v\u00e0 d\u01b0\u1edbi 250 nm, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 c\u1ee7a n\u01b0\u1edbc v\u00e0 melanin t\u01b0\u01a1ng \u1ee9ng cao h\u01a1n h\u1ec7 s\u1ed1 t\u00e1n x\u1ea1, d\u1eabn \u0111\u1ebfn kh\u00f4ng c\u00f3 hi\u1ec7n t\u01b0\u1ee3ng t\u00e1n x\u1ea1 [14]. S\u1ef1 t\u00e1n x\u1ea1 ch\u1ec9 x\u1ea3y ra trong kho\u1ea3ng 250 \u0111\u1ebfn 2500 nm. (T\u1ea5t nhi\u00ean, ngay c\u1ea3 \u1edf b\u01b0\u1edbc s\u00f3ng n\u00e0y, c\u00e1c melanosome v\u00e0 hemoglobin c\u0169ng \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5.) S\u1ef1 t\u00e1n x\u1ea1 x\u1ea3y ra ch\u1ee7 y\u1ebfu \u1edf l\u1edbp b\u00ec. Collagen l\u00e0 nguy\u00ean nh\u00e2n ch\u00ednh g\u00e2y ra hi\u1ec7n t\u01b0\u1ee3ng t\u00e1n x\u1ea1. Khi \u00e1nh s\u00e1ng \u0111i v\u00e0o da, s\u1ef1 t\u00e1n x\u1ea1 t\u0103ng l\u00ean v\u00e0 s\u1ed1 l\u01b0\u1ee3ng photon \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5 gi\u1ea3m. Khi h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 t\u0103ng, \u0111\u1ed9 xuy\u00ean s\u00e2u quang h\u1ecdc gi\u1ea3m. \u0110\u1ed9 s\u00e2u x\u00e2m nh\u1eadp quang h\u1ecdc c\u0169ng gi\u1ea3m theo h\u1ec7 s\u1ed1 t\u00e1n x\u1ea1.<\/p>\n

    Do \u0111\u00f3, m\u00f4 t\u1ea3 ch\u00ednh x\u00e1c h\u01a1n v\u1ec1 c\u00f4ng th\u1ee9c (xem “h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5”) s\u1ebd l\u00e0:<\/p>\n

    \"C\u00f4ng
    C\u00f4ng th\u1ee9c (xem “h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5”)<\/figcaption><\/figure>\n

    I (z)<\/em>: m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng b\u1ec1 m\u1eb7t \u1edf \u0111\u1ed9 s\u00e2u z.<\/p>\n

    k<\/em>: h\u1eb1ng s\u1ed1 t\u00ednh t\u00e1n x\u1ea1 ng\u01b0\u1ee3c.<\/p>\n

    \u03b4: \u0111\u1ed9 x\u00e2m nh\u1eadp quang h\u1ecdc ph\u1ee5 thu\u1ed9c v\u00e0o b\u01b0\u1edbc s\u00f3ng ho\u1eb7c \u0111\u1ed9 s\u00e2u c\u1ee7a \u00e1nh s\u00e1ng ho\u1eb7c \u0111\u1ed9 s\u00e2u m\u00e0 t\u1ea1i \u0111\u00f3 c\u00f3 s\u1ef1 suy gi\u1ea3m c\u00f2n 37% gi\u00e1 tr\u1ecb tr\u00ean b\u1ec1 m\u1eb7t (37% = 1\/e<\/em>, trong \u0111\u00f3 e <\/em>= 2,7, c\u01a1 s\u1ed1 c\u1ee7a logarit t\u1ef1 nhi\u00ean).<\/p>\n

    g<\/em>: h\u1ec7 s\u1ed1 d\u1ecb h\u01b0\u1edbng (gi\u00e1 tr\u1ecb c\u1ee7a “trung b\u00ecnh” h\u01b0\u1edbng c\u1ee7a c\u00e1c photon b\u1ecb t\u00e1n x\u1ea1). g <\/em>= 0,9 \u0111\u1ed1i v\u1edbi da.<\/p>\n

    \u00b5<\/em>a<\/em>: <\/em>h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5.<\/p>\n

    \u00b5<\/em>s<\/em>: h\u1ec7 s\u1ed1 t\u00e1n x\u1ea1.<\/p>\n

    \u0110\u1ed9 s\u00e2u x\u00e2m nh\u1eadp quang h\u1ecdc gi\u1ea3m khi h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 v\u00e0 h\u1ec7 s\u1ed1 t\u00e1n x\u1ea1 t\u0103ng [14]. S\u1ef1 t\u00e1n x\u1ea1 c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng quan s\u00e1t trong cu\u1ed9c s\u1ed1ng th\u1ef1c. Khi ch\u00fang ta d\u00f9ng tay che m\u1eb7t tr\u1eddi, c\u00f3 th\u1ec3 nh\u00ecn th\u1ea5y \u201cm\u00e0u \u0111\u1ecf\u201d c\u00f3 b\u01b0\u1edbc s\u00f3ng d\u00e0i v\u00e0 \u00edt b\u1ecb t\u00e1n x\u1ea1 qua b\u00e0n tay trong khi kh\u00f4ng th\u1ec3 nh\u00ecn th\u1ea5y \u201cm\u00e0u xanh\u201d. Nguy\u00ean t\u1eafc t\u01b0\u01a1ng t\u1ef1 c\u0169ng \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng cho hi\u1ec7n t\u01b0\u1ee3ng ho\u00e0ng h\u00f4n m\u00e0u \u0111\u1ecf r\u1ef1c.<\/p>\n

    \u0110\u1eb7c bi\u1ec7t, h\u1ec7 s\u1ed1 t\u00e1n x\u1ea1 c\u00f3 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn \u0111\u1ed9 s\u00e2u x\u00e2m nh\u1eadp nhi\u1ec1u h\u01a1n h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5. Trong v\u00f9ng \u00e1nh s\u00e1ng kh\u1ea3 ki\u1ebfn, x\u1ea3y ra 100 l\u1ea7n t\u00e1n x\u1ea1 tr\u01b0\u1edbc khi m\u1ed9t photon b\u1ecb h\u1ea5p th\u1ee5 [1], v\u00e0 trong tr\u01b0\u1eddng h\u1ee3p \u00e1nh s\u00e1ng \u0111\u1ecf, \u0111\u1ed9 d\u00e0i di chuy\u1ec3n trung b\u00ecnh cho \u0111\u1ebfn khi h\u1ea5p th\u1ee5 l\u00e0 50 \u00b5m. Chi\u1ec1u d\u00e0i di chuy\u1ec3n trung b\u00ecnh do t\u00e1n x\u1ea1 l\u00e0 5 mm, g\u1ea5p kho\u1ea3ng 100 l\u1ea7n [16].<\/p>\n

    T\u00e1n x\u1ea1 ng\u01b0\u1ee3c<\/h3>\n

    S\u1ef1 t\u00e1n x\u1ea1 c\u00f3 th\u1ec3 x\u1ea3y ra theo m\u1ecdi h\u01b0\u1edbng [17]. Ng\u01b0\u1eddi ta l\u1ea7m t\u01b0\u1edfng r\u1eb1ng c\u00f3 nhi\u1ec1u t\u00e1n x\u1ea1 ng\u01b0\u1ee3c h\u01a1n, nh\u01b0ng trong tr\u01b0\u1eddng h\u1ee3p t\u00e1n x\u1ea1 Mie, t\u00e1n x\u1ea1 thu\u1eadn \u0111\u01b0\u1ee3c bi\u1ebft l\u00e0 t\u00e1n x\u1ea1 ch\u00ednh [16]. Khi hi\u1ec7n t\u01b0\u1ee3ng t\u00e1n x\u1ea1 ng\u01b0\u1ee3c x\u1ea3y ra, nhi\u1ec1u photon t\u00edch t\u1ee5 tr\u00ean b\u1ec1 m\u1eb7t da v\u00e0 n\u0103ng l\u01b0\u1ee3ng t\u00edch lu\u1ef9 tr\u00ean b\u1ec1 m\u1eb7t cao h\u01a1n d\u1ef1 \u0111\u1ecbnh. Do \u0111\u00f3, b\u01b0\u1edbc s\u00f3ng ng\u1eafn h\u01a1n t\u00edch l\u0169y nhi\u1ec1u n\u0103ng l\u01b0\u1ee3ng h\u01a1n b\u01b0\u1edbc s\u00f3ng d\u00e0i h\u01a1n. H\u00e3y gi\u1ea3 \u0111\u1ecbnh nh\u1eefng \u0111i\u1ec1u sau \u0111\u1ec3 hi\u1ec3u r\u00f5. Gi\u1ea3 s\u1eed r\u1eb1ng b\u1ed1n photon trong s\u1ed1 m\u01b0\u1eddi photon \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5 \u1edf 0,1 mm t\u01b0\u01a1ng \u1ee9ng v\u1edbi \u0111\u1ed9 d\u00e0y c\u1ee7a l\u1edbp bi\u1ec3u b\u00ec v\u00e0 c\u00e1c photon \u1edf \u0111\u1ed9 s\u00e2u 0,2 mm t\u00ednh t\u1eeb b\u1ec1 m\u1eb7t b\u1ecb t\u00e1n x\u1ea1 ng\u01b0\u1ee3c d\u1eabn \u0111\u1ebfn th\u00eam m\u1ed9t photon h\u1ea5p th\u1ee5 \u1edf 0,1 mm. Trong tr\u01b0\u1eddng h\u1ee3p n\u00e0y, \u1edf \u0111\u1ed9 s\u00e2u 0,1 mm, c\u00f3 b\u1ed1n photon t\u1ea1o ra m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng 4 J\/cm2<\/sup>, nh\u01b0ng do t\u00e1n x\u1ea1 ng\u01b0\u1ee3c n\u00ean c\u00f3 t\u1ed5ng c\u1ed9ng n\u0103m photon d\u1eabn \u0111\u1ebfn n\u0103ng l\u01b0\u1ee3ng t\u0103ng l\u00ean 5 J\/cm2<\/sup>. K\u1ebft qu\u1ea3 l\u00e0 tia laser c\u00f3 b\u01b0\u1edbc s\u00f3ng ng\u1eafn h\u01a1n t\u00edch lu\u1ef9 nhi\u1ec1u n\u0103ng l\u01b0\u1ee3ng h\u01a1n n\u0103ng l\u01b0\u1ee3ng th\u1ef1c t\u1ebf tr\u00ean b\u1ec1 m\u1eb7t da. V\u00ed d\u1ee5, ngay c\u1ea3 khi c\u1ea3 hai laser 532 v\u00e0 755 nm \u0111\u01b0\u1ee3c chi\u1ebfu v\u1edbi c\u00f9ng m\u1ed9t m\u1ee9c n\u0103ng l\u01b0\u1ee3ng, th\u00ec laser 532 nm cho th\u1ea5y s\u1ef1 t\u00edch lu\u1ef9 n\u0103ng l\u01b0\u1ee3ng th\u1ef1c t\u1ebf cao h\u01a1n tr\u00ean b\u1ec1 m\u1eb7t da, d\u1eabn \u0111\u1ebfn t\u0103ng kh\u1ea3 n\u0103ng x\u1ea3y ra t\u00e1c d\u1ee5ng ph\u1ee5.<\/p>\n

    Ngo\u00e0i ra, do t\u00e1n x\u1ea1 ng\u01b0\u1ee3c, \u0111\u1ed9 xuy\u00ean s\u00e2u \u201cth\u1ef1c\u201d l\u00e0 s\u00e2u h\u01a1n \u0111\u1ed9 s\u00e2u x\u00e2m nh\u1eadp quang h\u1ecdc (OPD) [1]. Gi\u1ea3 s\u1eed b\u1ed1n trong s\u1ed1 m\u01b0\u1eddi photon xuy\u00ean qua \u1edf \u0111\u1ed9 s\u00e2u 2 mm v\u00e0 hai xuy\u00ean qua \u1edf 2,5 mm, v\u1edbi laser Nd: YAG 1064 nm. \u0110\u1ed9 xuy\u00ean s\u00e2u l\u00e0 \u0111\u1ed9 s\u00e2u m\u00e0 t\u1ea1i \u0111\u00f3 c\u00e1c photon gi\u1ea3m xu\u1ed1ng c\u00f2n e-1<\/sup>, t\u1ee9c l\u00e0 \u0111\u1ed9 s\u00e2u m\u00e0 t\u1ea1i \u0111\u00f3 m\u01b0\u1eddi photon tr\u1edf th\u00e0nh b\u1ed1n photon. OPD theo \u0111\u1ecbnh ngh\u0129a l\u00e0 s\u00e2u 2 mm, nh\u01b0ng n\u1ebfu hai photon c\u00f2n l\u1ea1i v\u01b0\u1ee3t qua \u0111\u1ed9 s\u00e2u 2,5 mm b\u1ecb t\u00e1n x\u1ea1 ng\u01b0\u1ee3c tr\u1edf l\u1ea1i \u0111i\u1ec3m 2,5 mm, th\u00ec c\u00f3 b\u1ed1n photon \u1edf 2,5 mm. Do \u0111\u00f3, \u0111\u1ed9 xuy\u00ean s\u00e2u “th\u1ef1c” l\u00e0 2,5 mm. \u0110\u1ed9 xuy\u00ean s\u00e2u th\u1ef1c s\u00e2u h\u01a1n OPD.<\/p>\n

    N\u1ebfu kh\u00f4ng x\u1ea3y ra hi\u1ec7n t\u01b0\u1ee3ng h\u1ea5p th\u1ee5 th\u00ec \u0111\u1ed9 xuy\u00ean s\u00e2u th\u1ef1c s\u1ebd s\u00e2u h\u01a1n. Trong tr\u01b0\u1eddng h\u1ee3p m\u00f4 s\u1eafc t\u1ed1, t\u1ea5t c\u1ea3 c\u00e1c photon t\u1eeb b\u01b0\u1edbc s\u00f3ng 532 nm \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5 trong m\u00f4 s\u1eafc t\u1ed1, d\u1eabn \u0111\u1ebfn \u0111\u1ed9 xuy\u00ean s\u00e2u n\u00f4ng (H\u00ecnh 3.8<\/em>).<\/p>\n

    \"\u0110\u1ed9
    \u0110\u1ed9 xuy\u00ean s\u00e2u c\u1ee7a tia laser v\u1edbi m\u00f4 c\u00f3 s\u1eafc t\u1ed1 \/kh\u00f4ng c\u00f3 s\u1eafc t\u1ed1.<\/figcaption><\/figure>\n

    H\u00ecnh 3.8 <\/strong>\u0110\u1ed9 xuy\u00ean s\u00e2u c\u1ee7a tia laser v\u1edbi m\u00f4 c\u00f3 s\u1eafc t\u1ed1 \/ kh\u00f4ng c\u00f3 s\u1eafc t\u1ed1.<\/p>\n

    Tuy nhi\u00ean, trong tr\u01b0\u1eddng h\u1ee3p kh\u00f4ng c\u00f3 m\u00f4 s\u1eafc t\u1ed1, s\u1ef1 h\u1ea5p th\u1ee5 s\u1ebd kh\u00f4ng x\u1ea3y ra v\u00e0 \u0111\u1ed9 xuy\u00ean s\u00e2u th\u1ef1c tr\u1edf n\u00ean s\u00e2u h\u01a1n.<\/p>\n

    T\u00f3m l\u1ea1i, OPD l\u00e0 m\u1ed9t gi\u00e1 tr\u1ecb c\u1ed1 \u0111\u1ecbnh \u0111\u01b0\u1ee3c t\u00ednh to\u00e1n v\u1ec1 m\u1eb7t to\u00e1n h\u1ecdc ho\u1eb7c v\u1eadt l\u00fd. Tuy nhi\u00ean, tr\u00ean th\u1ef1c t\u1ebf, OPD s\u00e2u h\u01a1n v\u00e0 c\u00f3 th\u1ec3 thay \u0111\u1ed5i t\u00f9y thu\u1ed9c v\u00e0o s\u1ef1 hi\u1ec7n di\u1ec7n c\u1ee7a m\u00f4 h\u1ea5p th\u1ee5 c\u0169ng nh\u01b0 l\u01b0\u1ee3ng collagen.<\/p>\n

    Ngo\u00e0i ra, khi \u0111i\u1ec1u tr\u1ecb \u1edf l\u1edbp b\u00ec (\u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u, tri\u1ec7t l\u00f4ng v\u00e0 x\u00f3a h\u00ecnh x\u0103m), x\u1eed l\u00fd s\u1eafc t\u1ed1 trong l\u1edbp bi\u1ec3u b\u00ec v\u00e0 sau \u0111\u00f3 \u0111i\u1ec1u tr\u1ecb \u1edf l\u1edbp b\u00ec cho ph\u00e9p c\u00e1c b\u00e1c s\u0129 laser \u0111i\u1ec1u tr\u1ecb c\u00e1c ph\u1ea7n s\u00e2u h\u01a1n c\u1ee7a da (H\u00ecnh 3.8<\/em>). Do \u0111\u00f3, m\u1ed9t quy tr\u00ecnh theo th\u1ee9 t\u1ef1 r\u1ea5t h\u1eefu \u00edch khi \u0111i\u1ec1u tr\u1ecb \u1edf l\u1edbp b\u00ec.<\/p>\n

    \u0110\u1ed9 d\u00e0i xung<\/h2>\n

    Th\u1eddi gian gi\u00e3n nhi\u1ec7t<\/h3>\n

    C\u00f3 ba c\u00e1ch \u0111\u1ec3 m\u1ea5t nhi\u1ec7t trong c\u00e1c m\u00f4: d\u1eabn nhi\u1ec7t, \u0111\u1ed1i l\u01b0u nhi\u1ec7t do m\u00e1u v\u00e0 b\u1ee9c x\u1ea1 nhi\u1ec7t [3]. Hai hi\u1ec7n t\u01b0\u1ee3ng sau ch\u1ec9 c\u00f3 \u00fd ngh\u0129a trong tr\u01b0\u1eddng h\u1ee3p xung d\u00e0i, v\u00e0 trong kho\u1ea3ng \u0111\u1ed9 d\u00e0i xung ng\u1eafn, d\u1eabn nhi\u1ec7t, truy\u1ec1n nhi\u1ec7t ra m\u00f4i tr\u01b0\u1eddng xung quanh, l\u00e0 c\u00e1ch t\u1ea3n nhi\u1ec7t ch\u00ednh. C\u00f4ng th\u1ee9c c\u1ee7a \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t do d\u1eabn nhi\u1ec7t nh\u01b0 sau [19]:<\/p>\n

    Z<\/em>therm <\/sub>(t)=\u221a4kt<\/p>\n

    Z<\/em>therm <\/sub>(t) – \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t<\/p>\n

    k – \u0111\u1ed9 d\u1eabn nhi\u1ec7t<\/p>\n

    t – th\u1eddi gian.<\/p>\n

    C\u00f4ng th\u1ee9c v\u1ec1 th\u1eddi gian gi\u00e3n nhi\u1ec7t \u0111\u01b0\u1ee3c t\u00ednh theo c\u00f4ng th\u1ee9c cho \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t. L\u00fd thuy\u1ebft v\u1ec1 quang nhi\u1ec7t c\u00f3 ch\u1ecdn l\u1ecdc ph\u00e1t bi\u1ec3u r\u1eb1ng \u201cn\u1ebfu m\u1ed9t l\u01b0\u1ee3ng nh\u1ecf n\u0103ng l\u01b0\u1ee3ng \u00e1nh s\u00e1ng \u0111\u01b0\u1ee3c chi\u1ebfu x\u1ea1 trong m\u1ed9t th\u1eddi gian ng\u1eafn, th\u00ec n\u0103ng l\u01b0\u1ee3ng \u00e1nh s\u00e1ng m\u00e0 m\u00f4 \u0111\u00edch nh\u1eadn \u0111\u01b0\u1ee3c ch\u1ec9 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 t\u0103ng nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 \u0111\u00edch v\u00e0 kh\u00f4ng truy\u1ec1n nhi\u1ec7t cho c\u00e1c m\u00f4 xung quanh\u201d. Do \u0111\u00f3, \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t kh\u00f4ng \u0111\u01b0\u1ee3c l\u1edbn h\u01a1n \u0111\u01b0\u1eddng k\u00ednh m\u1ee5c ti\u00eau c\u1ee7a m\u00f4 \u0111\u00edch v\u00e0 ph\u1ea3i b\u1eb1ng ho\u1eb7c ng\u1eafn h\u01a1n (\u0111\u01b0\u1eddng k\u00ednh m\u1ee5c ti\u00eau \u2265 \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t). Do \u0111\u00f3, th\u1eddi gian gi\u00e3n nhi\u1ec7t c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 th\u1eddi gian c\u1ee7a \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t khi \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t v\u00e0 \u0111\u01b0\u1eddng k\u00ednh m\u00f4 \u0111\u00edch l\u00e0 b\u1eb1ng nhau. Thay \u0111\u1ed5i th\u1eddi gian gi\u00e3n nhi\u1ec7t b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng c\u00f4ng th\u1ee9c cho \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t d\u1eabn \u0111\u1ebfn c\u00f4ng th\u1ee9c th\u1eddi gian gi\u00e3n nhi\u1ec7t (TRT).<\/p>\n

    \u03c4= \u03b4\/g\u03ba<\/p>\n

    \u03b4 \u2014 \u0111\u1ed9 xuy\u00ean s\u00e2u quang cho c\u00e1c l\u1edbp h\u1ea5p th\u1ee5 \u0111\u1ed3ng nh\u1ea5t.<\/p>\n

    \u03ba \u2014 \u0111\u1ed9 khu\u1ebfch t\u00e1n nhi\u1ec7t, m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng d\u1ef1a tr\u00ean \u0111\u1ed9 d\u1eabn nhi\u1ec7t v\u00e0 nhi\u1ec7t dung ri\u00eang c\u1ee7a m\u00f4i tr\u01b0\u1eddng.<\/p>\n

    g \u2014 h\u1eb1ng s\u1ed1 d\u1ef1a tr\u00ean h\u00ecnh d\u1ea1ng c\u1ee7a m\u1ee5c ti\u00eau (ph\u1eb3ng, h\u00ecnh tr\u1ee5 ho\u1eb7c h\u00ecnh c\u1ea7u).<\/p>\n

    Xem x\u00e9t kh\u00e1i ni\u1ec7m c\u1ee7a \u03b4 trong c\u00f4ng th\u1ee9c n\u00e0y. Trong \u201cCh\u01b0\u01a1ng 1\u201d, \u03b4 l\u00e0 \u0111\u01b0\u1eddng k\u00ednh c\u1ee7a m\u00f4 \u0111\u00edch, nh\u01b0ng \u0111\u1ecbnh ngh\u0129a ban \u0111\u1ea7u l\u00e0 \u0111\u1ed9 xuy\u00ean s\u00e2u quang h\u1ecdc \u0111\u1ed1i v\u1edbi c\u00e1c l\u1edbp h\u1ea5p th\u1ee5 \u0111\u1ed3ng nh\u1ea5t [14]. T\u1ea1i sao \u0111\u1ecbnh ngh\u0129a n\u00e0y l\u1ea1i xu\u1ea5t hi\u1ec7n?<\/p>\n

    Khi tia laser \u0111\u01b0\u1ee3c chi\u1ebfu v\u00e0o m\u1ee5c ti\u00eau nh\u1ecf (\u0111\u01b0\u1eddng k\u00ednh m\u1ee5c ti\u00eau <OPD, \u03b1d <\/em><1) th\u00ec t\u1ea5t c\u1ea3 c\u00e1c photon c\u00f3 th\u1ec3 \u0111i qua n\u00f3 [9]. Nh\u01b0ng khi m\u00f4 \u0111\u00edch r\u1ea5t l\u1edbn (\u0111\u01b0\u1eddng k\u00ednh m\u1ee5c ti\u00eau> OPD, \u03b1d<\/em>> 1), c\u00e1c photon ch\u1ec9 chi\u1ebfu m\u1ed9t ph\u1ea7n c\u1ee7a m\u00f4 \u0111\u00edch (H\u00ecnh 3.9<\/em>). T\u1ea1i th\u1eddi \u0111i\u1ec3m n\u00e0y, chi\u1ec1u d\u00e0i c\u1ee7a ph\u1ea7n m\u00f4 \u0111\u00edch b\u1ecb \u1ea3nh h\u01b0\u1edfng b\u1edfi tia laser l\u00e0 OPD. N\u00f3i c\u00e1ch kh\u00e1c, khi \u201c\u0111\u01b0\u1eddng k\u00ednh m\u1ee5c ti\u00eau <OPD\u201d, \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t b\u1eb1ng \u0111\u01b0\u1eddng k\u00ednh c\u1ee7a m\u00f4 \u0111\u00edch. Nh\u01b0ng khi \u201c\u0111\u01b0\u1eddng k\u00ednh m\u1ee5c ti\u00eau > OPD\u201d, \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t kh\u00f4ng b\u1eb1ng \u0111\u01b0\u1eddng k\u00ednh m\u00e0 b\u1eb1ng OPD (\u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t = \u0111\u1ed9 xuy\u00ean s\u00e2u quang). Th\u00eam n\u1eefa, trong c\u1ea3 hai tr\u01b0\u1eddng h\u1ee3p, \u0111\u1ed9 d\u1eabn nhi\u1ec7t (k) ph\u1ea3i gi\u1ed1ng nhau \u0111\u1ec3 \u00e1p d\u1ee5ng c\u00f4ng th\u1ee9c c\u1ee7a \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t. N\u00f3i c\u00e1ch kh\u00e1c, m\u00f4 \u0111\u00edch b\u1ecb \u1ea3nh h\u01b0\u1edfng b\u1edfi tia laser ph\u1ea3i l\u00e0 m\u1ed9t m\u00f4 \u0111\u1ed3ng nh\u1ea5t.<\/p>\n

    \"M\u1ed1i
    M\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c m\u00f4 \u0111\u00edch v\u00e0 OPD<\/figcaption><\/figure>\n

    H\u00ecnh<\/strong> 3.9<\/strong> M\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c m\u00f4 \u0111\u00edch v\u00e0 OPD. Tr\u00e1i (\u0111\u01b0\u1eddng k\u00ednh m\u1ee5c ti\u00eau <OPD, \u03b1d <\/em><1), Ph\u1ea3i (\u0111\u01b0\u1eddng k\u00ednh m\u1ee5c ti\u00eau> OPD, \u03b1d<\/em>> 1).<\/p>\n

    \u0110\u1ec3 t\u00f3m t\u1eaft c\u00e1c ph\u1ea7n chung trong c\u1ea3 hai t\u00ecnh hu\u1ed1ng, tr\u01b0\u1edbc ti\u00ean, nhi\u1ec7t ph\u1ea3i \u0111\u01b0\u1ee3c t\u1ea1o ra trong OPD. Th\u1ee9 hai, c\u00e1c m\u00f4 \u0111\u00edch ph\u1ea3i \u0111\u1ed3ng nh\u1ea5t. Do \u0111\u00f3, \u03b4 \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a nh\u01b0 sau: \u201c\u0111\u1ed9 xuy\u00ean s\u00e2u quang \u0111\u1ed1i v\u1edbi c\u00e1c l\u1edbp h\u1ea5p th\u1ee5 \u0111\u1ed3ng nh\u1ea5t\u201d.<\/p>\n

    V\u00ec \u0111\u1ecbnh ngh\u0129a c\u1ee7a \u03b4 c\u00f3 hai ti\u1ec1n \u0111\u1ec1 n\u00ean c\u00f3 hai kh\u00e1i ni\u1ec7m v\u1ec1 TRT [1]. \u0110\u1ea7u ti\u00ean, v\u00ec OPD kh\u00e1c nhau t\u00f9y theo b\u01b0\u1edbc s\u00f3ng, TRT c\u00f3 th\u1ec3 thay \u0111\u1ed5i t\u00f9y theo b\u01b0\u1edbc s\u00f3ng. Th\u1ee9 hai, da c\u00f3 nhi\u1ec1u th\u00e0nh ph\u1ea7n v\u00e0 th\u1ec3 nhi\u1ec5m s\u1eafc kh\u00e1c nhau, nh\u01b0ng v\u1ec1 t\u00ednh d\u1eabn nhi\u1ec7t, da l\u00e0 m\u1ed9t m\u00f4 \u0111\u1ed3ng nh\u1ea5t c\u00f3 c\u00f9ng \u0111\u1ed9 khu\u1ebfch t\u00e1n nhi\u1ec7t. Trong ch\u1ea5t l\u1ecfng v\u00e0 h\u1ea7u h\u1ebft c\u00e1c m\u00f4, \u0111\u1ed9 khu\u1ebfch t\u00e1n nhi\u1ec7t l\u00e0 1,4 \u00d7 10\u22127<\/sup> m2<\/sup> s [19] ho\u1eb7c 1,3 \u00d7 10\u22123<\/sup> cm2<\/sup>\/s t\u00f9y thu\u1ed9c v\u00e0o t\u00e0i li\u1ec7u [1]. T\u1ea1i th\u1eddi \u0111i\u1ec3m n\u00e0y, y\u1ebfu t\u1ed1 x\u00e1c \u0111\u1ecbnh \u0111\u1ed9 xuy\u00ean s\u00e2u nhi\u1ec7t l\u00e0 th\u1eddi gian, t\u1ee9c l\u00e0 \u0111\u1ed9 d\u00e0i xung. Do \u0111\u00f3, TRT c\u00f3 th\u1ec3 thay \u0111\u1ed5i t\u00f9y theo \u0111\u1ed9 d\u00e0i xung.<\/p>\n

    TRT x\u00e1c \u0111\u1ecbnh b\u1eb1ng b\u01b0\u1edbc s\u00f3ng<\/h3>\n

    TRT c\u00f3 th\u1ec3 thay \u0111\u1ed5i t\u00f9y theo b\u01b0\u1edbc s\u00f3ng. Trong tr\u01b0\u1eddng h\u1ee3p th\u1ec3 nhi\u1ec5m s\u1eafc n\u1eb1m \u1edf kh\u1eafp n\u01a1i tr\u00ean da, ch\u1eb3ng h\u1ea1n nh\u01b0 n\u01b0\u1edbc, OPD kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o c\u1ea5u tr\u00fac da (l\u1edbp bi\u1ec3u b\u00ec, l\u1edbp \u0111\u00e1y, melanosomes, v.v.) m\u00e0 ph\u1ee5 thu\u1ed9c v\u00e0o b\u01b0\u1edbc s\u00f3ng [1]. V\u00ed d\u1ee5, laser 1540 nm c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 n\u01b0\u1edbc th\u1ea5p v\u00e0 xuy\u00ean s\u00e2u, v\u1edbi OPD v\u00e0i tr\u0103m micromet. Nh\u01b0 v\u1eady, TRT l\u00e0 v\u00e0i tr\u0103m gi\u00e2y. Ng\u01b0\u1ee3c l\u1ea1i, laser CO2 c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 cao \u0111\u1ed1i v\u1edbi n\u01b0\u1edbc c\u00f3 OPD n\u00f4ng v\u1edbi TRT nh\u1ecf h\u01a1n 1 ms. Laser Er: YAG th\u1eadm ch\u00ed c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 n\u01b0\u1edbc cao h\u01a1n so v\u1edbi laser CO2, v\u1edbi TRT l\u00e0 1 \u00b5s. Do \u0111\u00f3, OPD c\u00e0ng n\u00f4ng th\u00ec TRT c\u00e0ng ng\u1eafn. \u0110\u1ed1i v\u1edbi n\u01b0\u1edbc, TRT thay \u0111\u1ed5i t\u00f9y theo b\u01b0\u1edbc s\u00f3ng. Do \u0111\u00f3, khi m\u00f4 t\u1ea3 TRT c\u1ee7a n\u01b0\u1edbc, c\u1ea7n \u0111\u1ec1 c\u1eadp \u0111\u1ebfn c\u1ea3 b\u01b0\u1edbc s\u00f3ng v\u00e0 laser, ch\u1eb3ng h\u1ea1n nh\u01b0 \u201c<1 ms trong laser CO2\u201d ho\u1eb7c \u201c1 \u00b5s trong laser Er: YAG.\u201d<\/p>\n

    TRT x\u00e1c \u0111\u1ecbnh b\u1eb1ng c\u1ea5u tr\u00fac da<\/h3>\n

    TRT c\u00f3 th\u1ec3 ph\u1ee5 thu\u1ed9c v\u00e0o c\u1ea5u tr\u00fac da. V\u00ed d\u1ee5: c\u00e1c melanosome c\u00f3 TRT l\u00e0 347,2 ns v\u1edbi k\u00edch th\u01b0\u1edbc 1 \u00b5m, v\u00e0 l\u1edbp \u0111\u00e1y c\u1ee7a bi\u1ec3u b\u00ec n\u01a1i c\u00e1c t\u1ebf b\u00e0o s\u1eebng c\u00f3 melanosomes c\u00f3 TRT l\u00e0 0,1 ms v\u1edbi \u0111\u1ed9 d\u00e0y 10 \u00b5m, v\u00e0 l\u1edbp bi\u1ec3u b\u00ec v\u1edbi t\u1ed5ng c\u00e1c t\u1ebf b\u00e0o s\u1eebng c\u00f3 melanosomes c\u00f3 TRT l\u00e0 10 ms v\u1edbi \u0111\u1ed9 d\u00e0y 100 \u00b5m.<\/p>\n

    T\u1ea1i sao TRT thay \u0111\u1ed5i theo c\u1ea5u tr\u00fac da? Trong tr\u01b0\u1eddng h\u1ee3p c\u1ee7a laser Q-Switch, nhi\u1ec7t ch\u1ec9 gi\u1edbi h\u1ea1n \u1edf melanosome, t\u1ee9c l\u00e0, ph\u00e2n b\u1ed1 kh\u00f4ng \u0111\u1ed3ng \u0111\u1ec1u. Do \u0111\u00f3, sau khi tia laser \u0111\u01b0\u1ee3c chi\u1ebfu, nhi\u1ec7t s\u1ebd \u0111\u01b0\u1ee3c truy\u1ec1n \u0111\u1ebfn l\u1edbp tr\u00ean c\u1ee7a bi\u1ec3u b\u00ec, trong khi c\u00e1c melanosome v\u00e0 l\u1edbp \u0111\u00e1y ngu\u1ed9i \u0111i. M\u1eb7t kh\u00e1c, trong tr\u01b0\u1eddng h\u1ee3p laser xung d\u00e0i, v\u00ed d\u1ee5, khi \u0111\u01b0\u1ee3c chi\u1ebfu x\u1ea1 v\u1edbi 10 ms, nhi\u1ec7t c\u1ee7a c\u00e1c melanosome \u0111\u01b0\u1ee3c truy\u1ec1n \u0111\u1ebfn l\u1edbp \u0111\u00e1y ho\u1eb7c to\u00e0n b\u1ed9 l\u1edbp bi\u1ec3u b\u00ec v\u1edbi \u0111\u1ed9 d\u00e0i xung t\u01b0\u01a1ng \u0111\u1ed1i d\u00e0i h\u01a1n so v\u1edbi laser Q-switched, d\u1eabn \u0111\u1ebfn ph\u00e2n b\u1ed1 nhi\u1ec7t \u0111\u1ed3ng \u0111\u1ec1u. Do \u0111\u00f3, m\u1eb7c d\u00f9 kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t v\u1ec1 m\u1eb7t m\u00f4 h\u1ecdc, nh\u01b0ng s\u1ef1 ph\u00e2n b\u1ed1 nhi\u1ec7t l\u00e0 \u0111\u1ed3ng \u0111\u1ec1u. V\u00ec v\u1eady, ngay c\u1ea3 \u1edf c\u00f9ng m\u1ed9t b\u01b0\u1edbc s\u00f3ng, vi\u1ec7c \u0111i\u1ec1u ch\u1ec9nh \u0111\u1ed9 d\u00e0i xung c\u00f3 th\u1ec3 thay \u0111\u1ed5i TRT v\u00e0 thay \u0111\u1ed5i m\u1ee5c ti\u00eau mong mu\u1ed1n. M\u1ed9t v\u00ed d\u1ee5 l\u00e0 laser xung d\u00e0i \u0111\u01a1n v\u1ecb mili gi\u00e2y \u0111\u01b0\u1ee3c d\u00f9ng \u0111i\u1ec1u tr\u1ecb s\u1eafc t\u1ed1 bi\u1ec3u b\u00ec, m\u1ea1ch m\u00e1u v\u00e0 tri\u1ec7t l\u00f4ng.<\/p>\n

    Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c gi\u1ea3i th\u00edch b\u1eb1ng l\u00fd thuy\u1ebft m\u1edf r\u1ed9ng n\u00f3i tr\u00ean v\u1ec1 qu\u00e1 tr\u00ecnh quang nhi\u1ec7t c\u00f3 ch\u1ecdn l\u1ecdc. T\u00ecnh hu\u1ed1ng \u00e1p d\u1ee5ng l\u00fd thuy\u1ebft m\u1edf r\u1ed9ng l\u00e0 khi m\u00f4 kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t, nh\u01b0ng khi ph\u00e2n b\u1ed1 nhi\u1ec7t l\u00e0 \u0111\u1ed3ng \u0111\u1ec1u.<\/p>\n

    Trong B\u1ea3ng 3.2 <\/em>(\u0111\u01b0\u1ee3c \u0111\u1ec1 c\u1eadp trong \u201cCh\u01b0\u01a1ng 1\u201d), ch\u00fang ta c\u00f3 th\u1ec3 th\u1ea5y r\u1eb1ng TRT thay \u0111\u1ed5i t\u00f9y thu\u1ed9c v\u00e0o c\u1ea5u tr\u00fac da ho\u1eb7c b\u01b0\u1edbc s\u00f3ng c\u1ee7a tia laser. Ngo\u00e0i ra, m\u1ed9t \u0111i\u1ec1u n\u1eefa c\u1ea7n suy ngh\u0129 trong b\u1ea3ng n\u00e0y l\u00e0 kh\u00f4ng c\u00f3 TRT cho melanin v\u00e0 hemoglobin, c\u1ea3 hai \u0111\u1ec1u l\u00e0 th\u00e0nh ph\u1ea7n c\u1ee7a ba th\u1ec3 nhi\u1ec5m s\u1eafc ch\u00ednh. T\u1ea1i sao nh\u01b0 v\u1eady? T\u00f4i ngh\u0129, th\u1ee9 nh\u1ea5t l\u00e0 do melanin v\u00e0 hemoglobin c\u00f3 TRT qu\u00e1 ng\u1eafn n\u00ean ch\u01b0a th\u1ec3 t\u1ea1o ra tia laser c\u00f3 \u0111\u1ed3 d\u00e0i xung ph\u00f9 h\u1ee3p v\u1edbi TRT n\u00e0y. Th\u1ee9 hai, l\u00fd thuy\u1ebft \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng cho \u0111i\u1ec1u tr\u1ecb b\u1eb1ng laser trong th\u1ef1c t\u1ebf kh\u00f4ng ph\u1ea3i l\u00e0 qu\u00e1 tr\u00ecnh quang nhi\u1ec7t ch\u1ecdn l\u1ecdc m\u00e0 l\u00e0 l\u00fd thuy\u1ebft m\u1edf r\u1ed9ng v\u1ec1 qu\u00e1 tr\u00ecnh quang nhi\u1ec7t ch\u1ecdn l\u1ecdc.<\/p>\n

    B\u1ea3ng 3.2 <\/strong>TRT c\u1ea7n nh\u1edb TRT c\u1ea7n nh\u1edb<\/p>\n\n\n\n\n\n\n\n\n\n\n
    Melanosome<\/td>\n<1 \u00b5s (250\u20131000 ns)<\/td>\n<\/tr>\n
    S\u1eafc t\u1ed1 h\u00ecnh x\u0103m<\/td>\n20 ns ~ 3 ms<\/td>\n<\/tr>\n
    Melanocyte<\/td>\n1\u201330 \u00b5s<\/td>\n<\/tr>\n
    L\u1edbp \u0111\u00e1y<\/td>\n0.4 ms<\/td>\n<\/tr>\n
    Bi\u1ec3u b\u00ec<\/td>\n2ms (1\u201310ms)<\/td>\n<\/tr>\n
    Mao m\u1ea1ch<\/td>\n4,5 ms (100 \u00b5m: 100 \u00b5m t\u01b0\u01a1ng \u1ee9ng v\u1edbi k\u00edch th\u01b0\u1edbc c\u1ee7a m\u1ea1ch m\u00e1u nh\u1ecf nh\u1ea5t c\u00f3<\/p>\n

    th\u1ec3 nh\u00ecn th\u1ea5y)<\/td>\n<\/tr>\n

    Nang l\u00f4ng<\/td>\n40 ms (10\u2013100 ms)<\/td>\n<\/tr>\n
    N\u01b0\u1edbc<\/td>\n<1 ms trong laser CO2, 1<\/p>\n

    \u00b5s trong Er: YAG<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    B\u1ea3ng 3.2 <\/em>cho th\u1ea5y r\u1eb1ng TRT c\u1ee7a melanocyte l\u00e0 1\u201330 \u00b5s, nh\u01b0ng t\u01b0\u01a1ng t\u1ef1 nh\u01b0 v\u1eady, laser v\u1edbi \u0111\u1ed9 d\u00e0i xung n\u00e0y v\u1eabn ch\u01b0a c\u00f3. V\u00ec v\u1eady, hi\u1ec7n t\u1ea1i, ch\u00fang ta kh\u00f4ng th\u1ec3 x\u1eed l\u00fd c\u00e1c t\u1ebf b\u00e0o ph\u00f9 h\u1ee3p v\u1edbi TRT nh\u01b0 melanocyte v\u00e0 ch\u1ec9 c\u00f3 th\u1ec3 x\u1eed l\u00fd c\u00e1c l\u1edbp t\u1ebf b\u00e0o nh\u01b0 l\u1edbp \u0111\u00e1y. Tuy nhi\u00ean, c\u00f3 th\u1ec3 x\u1eed l\u00fd t\u1ebf b\u00e0o b\u1eb1ng hi\u1ec7u \u1ee9ng c\u01a1 quang m\u00e0 kh\u00f4ng c\u1ea7n \u00e1p d\u1ee5ng TRT.<\/p>\n

    K\u00edch th\u01b0\u1edbc \u0111i\u1ec3m<\/h2>\n

    Quy t\u1eafc ng\u00f3n tay c\u00e1i trong k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m<\/h3>\n

    H\u00e3y xem l\u1ea1i c\u00e1ch \u0111i\u1ec1u ch\u1ec9nh k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m khi \u0111i\u1ec1u tr\u1ecb l\u1edbp b\u00ec. V\u00ed d\u1ee5, v\u00ec c\u00e1c m\u1ea1ch m\u00e1u n\u1eb1m \u1edf c\u00e1c \u0111\u1ed9 s\u00e2u kh\u00e1c nhau c\u1ee7a l\u1edbp b\u00ec, OPD s\u00e2u h\u01a1n \u0111\u01b0\u1ee3c \u01b0u ti\u00ean h\u01a1n. N\u1ebfu v\u1eady, k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m n\u00ean \u0111\u01b0\u1ee3c t\u0103ng l\u00ean \u0111\u1ec3 OPD tr\u1edf n\u00ean s\u00e2u h\u01a1n. Nh\u01b0ng ngay c\u1ea3 v\u1edbi c\u00f9ng m\u1ed9t m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng, k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn h\u01a1n \u0111\u00f2i h\u1ecfi nhi\u1ec1u photon h\u01a1n \u0111\u1ec3 chi\u1ebfu x\u1ea1, do \u0111\u00f3, \u0111\u00f2i h\u1ecfi n\u0103ng l\u01b0\u1ee3ng cao h\u01a1n. Nh\u01b0ng v\u00ec m\u1ed7i m\u00e1y laser c\u00f3 gi\u1edbi h\u1ea1n v\u1ec1 n\u0103ng l\u01b0\u1ee3ng, n\u00f3 kh\u00f4ng th\u1ec3 duy tr\u00ec m\u1ed9t m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng nh\u1ea5t \u0111\u1ecbnh ngo\u00e0i m\u1ed9t k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ea5t \u0111\u1ecbnh. V\u00ec v\u1eady, \u0111i\u1ec1u c\u1ea7n thi\u1ebft \u0111\u1ec3 t\u00ecm m\u1ed9t k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m ph\u00f9 h\u1ee3p. K\u00edch th\u01b0\u1edbc \u0111i\u1ec3m n\u00ean l\u1edbn nh\u01b0 th\u1ebf n\u00e0o?<\/p>\n

    M\u1ed9t t\u00e0i li\u1ec7u laser \u0111\u1ec1 xu\u1ea5t \u201cquy t\u1eafc ng\u00f3n tay c\u00e1i v\u1ec1 k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m\u201d n\u00ean b\u1eb1ng kho\u1ea3ng m\u01b0\u1eddi l\u1ea7n \u0111\u1ed9 s\u00e2u m\u1ee5c ti\u00eau, \u201cd\u1ef1a tr\u00ean \u0111\u1ed9 s\u00e2u c\u1ee7a m\u00f4 \u0111\u00edch\u201d [2]. V\u00ed d\u1ee5, \u0111\u1ed9 s\u00e2u c\u1ee7a t\u1ed5n th\u01b0\u01a1ng bi\u1ec3u b\u00ec l\u00e0 0,1 mm n\u00ean k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m n\u00ean l\u00e0 1 mm. \u0110\u1ed9 s\u00e2u c\u1ee7a b\u1edbt r\u01b0\u1ee3u vang (PWS), h\u00ecnh x\u0103m v\u00e0 l\u00f4ng l\u1ea7n l\u01b0\u1ee3t l\u00e0 1, 2 v\u00e0 3 mm, v\u00ec v\u1eady k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m t\u01b0\u01a1ng \u1ee9ng ph\u1ea3i l\u00e0 10, 20 v\u00e0 30 mm. Tuy nhi\u00ean, t\u00f4i ngh\u0129 r\u1eb1ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m \u0111\u01b0\u1ee3c tr\u00ecnh b\u00e0y trong t\u00e0i li\u1ec7u n\u00e0y l\u00e0 qu\u00e1 l\u1edbn. T\u00f4i ngh\u0129 r\u1eb1ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m t\u1ed1i \u0111a g\u1ea5p 5 l\u1ea7n \u0111\u1ed9 s\u00e2u m\u1ee5c ti\u00eau. V\u00ed d\u1ee5, trong tr\u01b0\u1eddng h\u1ee3p tri\u1ec7t l\u00f4ng b\u1eb1ng laser, v\u00ec k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 10 mm \u0111\u01b0\u1ee3c cho l\u00e0 \u0111\u1ee7 \u0111\u1ec3 tri\u1ec7t l\u00f4ng, 15 mm, g\u1ea5p 5 l\u1ea7n \u0111\u1ed9 s\u00e2u 3 mm, c\u00f3 l\u1ebd l\u00e0 k\u00edch th\u01b0\u1edbc t\u1ed1i \u0111a. Ti\u1ebfn s\u0129 Minho Lee \u0111\u1ec1 xu\u1ea5t “Quy t\u1eafc m\u1ed9t n\u1eeda” v\u00ec \u1edf k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf h\u01a1n 10 mm, m\u1ed9t n\u1eeda k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m t\u01b0\u01a1ng \u1ee9ng v\u1edbi \u0111\u1ed9 s\u00e2u m\u1ee5c ti\u00eau (hai l\u1ea7n \u0111\u1ed9 s\u00e2u m\u1ee5c ti\u00eau) v\u00e0 m\u1ee5c ti\u00eau \u1edf \u0111\u1ed9 s\u00e2u n\u00e0y c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c x\u1eed l\u00fd. M\u1eb7t kh\u00e1c, Ross et al. n\u00f3i r\u1eb1ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m ph\u1ea3i l\u1edbn h\u01a1n OPD \u00edt nh\u1ea5t b\u1ed1n l\u1ea7n [22].<\/p>\n

    Hi\u1ec7u \u1ee9ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m<\/h3>\n

    H\u00e3y xem x\u00e9t k\u1ef9 h\u01a1n hi\u1ec7u \u1ee9ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 trong \u201cCh\u01b0\u01a1ng 1\u201d.<\/p>\n

    Trong \u201cCh\u01b0\u01a1ng 1\u201dch\u00fang t\u00f4i cho r\u1eb1ng c\u00f3 m\u1ed9t k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn 1 cm2<\/sup> v\u00e0 m\u1ed9t k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf 0,5 cm2<\/sup>, l\u1ea7n l\u01b0\u1ee3t 10 v\u00e0 5 photon \u0111\u01b0\u1ee3c b\u1eafn ra, v\u00e0 m\u1ed9t photon n\u1eb1m trong khu v\u1ef1c b\u00ean ngo\u00e0i OPD. T\u00e1m photon s\u1ebd \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5 \u1edf k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn v\u00e0 3 \u1edf k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf (H\u00ecnh 3.10<\/em>). M\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng l\u00e0 s\u1ed1 l\u01b0\u1ee3ng photon tr\u00ean m\u1ed9t \u0111\u01a1n v\u1ecb di\u1ec7n t\u00edch, do \u0111\u00f3 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ee7a laser l\u00e0 10 J\/cm2<\/sup> \u1edf c\u1ea3 hai k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m, nh\u01b0ng b\u00ean trong da, m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng kh\u00e1c nhau (t\u01b0\u01a1ng \u1ee9ng l\u00e0 8 J\/cm2<\/sup> v\u00e0 6 J\/m2<\/sup>). N\u00f3i c\u00e1ch kh\u00e1c, k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m c\u00e0ng l\u1edbn th\u00ec n\u0103ng l\u01b0\u1ee3ng th\u1ef1c t\u1ebf tr\u00ean da c\u00e0ng cao. L\u00fd do c\u1ee7a \u0111i\u1ec1u n\u00e0y l\u00e0 v\u00ec c\u00e1c photon b\u1ecb l\u1ec7ch kh\u1ecfi h\u01b0\u1edbng tia v\u00e0 do \u0111\u00f3 kh\u00f4ng b\u1ecb h\u1ea5p th\u1ee5 l\u00e0 m\u1ed9t \u201ch\u1eb1ng s\u1ed1\u201d v\u00e0 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng l\u00e0 m\u1ed9t \u201ct\u1ef7 l\u1ec7\u201d.<\/p>\n

    T\u00f3m l\u1ea1i, n\u0103ng l\u01b0\u1ee3ng trong da t\u01b0\u01a1ng \u0111\u1ed1i th\u1ea5p \u1edf k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf v\u00e0 t\u01b0\u01a1ng \u0111\u1ed1i cao \u1edf k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn. V\u00ec v\u1eady, ch\u00fang ta n\u00ean l\u00e0m g\u00ec khi chuy\u1ec3n \u0111\u1ed5i k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m trong c\u00f9ng m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng? Gi\u1ea3m k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m \u1edf c\u00f9ng m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng s\u1ebd d\u1eabn \u0111\u1ebfn n\u0103ng l\u01b0\u1ee3ng h\u1ea5p th\u1ee5 th\u1ea5p h\u01a1n, kh\u00f4ng g\u00e2y t\u00e1c d\u1ee5ng ph\u1ee5, nh\u01b0ng \u00edt hi\u1ec7u qu\u1ea3 h\u01a1n. N\u1ebfu k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m \u0111\u01b0\u1ee3c t\u0103ng l\u00ean, n\u0103ng l\u01b0\u1ee3ng th\u1ef1c t\u1ebf tr\u1edf n\u00ean cao h\u01a1n n\u0103ng l\u01b0\u1ee3ng ban \u0111\u1ea7u, do \u0111\u00f3 c\u00f3 kh\u1ea3 n\u0103ng cao x\u1ea3y ra t\u00e1c d\u1ee5ng ph\u1ee5. V\u00ec v\u1eady, khi t\u0103ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m, n\u00ean gi\u1ea3m m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng.<\/p>\n

    V\u1eady, ch\u00fang ta n\u00ean l\u00e0m g\u00ec \u0111\u1ec3 c\u00f3 \u0111\u01b0\u1ee3c n\u0103ng l\u01b0\u1ee3ng \u0111\u1ed3ng \u0111\u1ec1u trong da \u1edf c\u00e1c k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m kh\u00e1c nhau? H\u00ecnh 3.11 <\/em>cho th\u1ea5y s\u1ed1 l\u01b0\u1ee3ng photon \u0111\u01b0\u1ee3c chuy\u1ec3n \u0111\u1ed5i th\u00e0nh m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng t\u1eeb H\u00ecnh 3.10<\/em>. Tr\u01b0\u1edbc ti\u00ean, \u1edf 10 J\/cm2<\/sup> c\u1ee7a tay c\u1ea7m, m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng trong da l\u00e0 8 J\/cm2<\/sup> \u0111\u1ed1i v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn v\u00e0 6 J\/cm2<\/sup> \u0111\u1ed1i v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf. \u0110\u1ec3 t\u1ea1o ra n\u0103ng l\u01b0\u1ee3ng t\u01b0\u01a1ng \u0111\u01b0\u01a1ng tr\u00ean da v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf, c\u1ea7n t\u0103ng m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng<\/p>\n

    c\u1ee7a tay c\u1ea7m. \u0110\u1ec3 t\u1ea1o ra c\u00f9ng m\u1ed9t n\u0103ng l\u01b0\u1ee3ng 8 J\/cm2<\/sup> tr\u00ean da v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf, n\u0103ng l\u01b0\u1ee3ng ph\u1ea3i \u0111\u01b0\u1ee3c n\u00e2ng l\u00ean tr\u00ean n\u0103ng l\u01b0\u1ee3ng ban \u0111\u1ea7u c\u1ee7a tay c\u1ea7m l\u00e0 10 J\/cm2<\/sup>, v\u00ed d\u1ee5, n\u00f3 ph\u1ea3i \u0111\u01b0\u1ee3c n\u00e2ng l\u00ean 12 J\/cm2<\/sup>. \u0110i\u1ec1u quan tr\u1ecdng c\u1ea7n l\u01b0u \u00fd l\u00e0 s\u1ef1 t\u00e1n x\u1ea1 x\u1ea3y ra ch\u1ee7 y\u1ebfu \u1edf l\u1edbp b\u00ec. S\u1ef1 t\u00e1n x\u1ea1 kh\u00f4ng x\u1ea3y ra \u1edf l\u1edbp bi\u1ec3u b\u00ec. N\u0103ng l\u01b0\u1ee3ng c\u1ee7a k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn trong l\u1edbp bi\u1ec3u b\u00ec l\u00e0 10 J\/cm2<\/sup> nh\u01b0ng n\u0103ng l\u01b0\u1ee3ng c\u1ee7a k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf l\u00e0 12 J\/cm2<\/sup>.<\/p>\n

    \"S\u1ed1
    S\u1ed1 l\u01b0\u1ee3ng photon theo k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m.<\/figcaption><\/figure>\n

    H\u00ecnh 3.10 <\/strong>S\u1ed1 l\u01b0\u1ee3ng photon theo k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m. Khi gi\u1ea3 s\u1eed r\u1eb1ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u00e0 1 cm2<\/sup>, 0,5 cm2<\/sup> v\u00e0 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng l\u00e0 10 J\/cm2<\/sup> th\u00ec s\u1ed1 l\u01b0\u1ee3ng photon \u0111\u01b0\u1ee3c gi\u1ea3 thi\u1ebft l\u1ea7n l\u01b0\u1ee3t l\u00e0 10 v\u00e0 5.<\/p>\n

    \"S\u1ed1
    S\u1ed1 l\u01b0\u1ee3ng c\u00e1c photon \u0111\u01b0\u1ee3c chuy\u1ec3n \u0111\u1ed5i th\u00e0nh m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng t\u1eeb<\/figcaption><\/figure>\n

    H\u00ecnh<\/strong> 3.11<\/strong> S\u1ed1 l\u01b0\u1ee3ng c\u00e1c photon \u0111\u01b0\u1ee3c chuy\u1ec3n \u0111\u1ed5i th\u00e0nh m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng t\u1eeb H\u00ecnh 3.10. Gi\u00e1 tr\u1ecb c\u1ee7a \u201ck\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf\u201d l\u00e0 gi\u00e1 tr\u1ecb gi\u1ea3 \u0111\u1ecbnh c\u1ee7a m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ea7n thi\u1ebft cho l\u1edbp bi\u1ec3u b\u00ec v\u00e0 tay c\u1ea7m khi \u0111i\u1ec1u ch\u1ec9nh m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ee7a l\u1edbp b\u00ec th\u00e0nh 8 J\/cm2<\/sup>.<\/p>\n

    N\u00f3i c\u00e1ch kh\u00e1c, k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ecf c\u00f3 n\u0103ng l\u01b0\u1ee3ng \u1edf bi\u1ec3u b\u00ec t\u01b0\u01a1ng \u0111\u1ed1i cao so v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn v\u00e0 c\u00f3 nhi\u1ec1u kh\u1ea3 n\u0103ng g\u00e2y ra t\u00e1c d\u1ee5ng ph\u1ee5 tr\u00ean l\u1edbp bi\u1ec3u b\u00ec. V\u00ec v\u1eady, \u0111\u1ec3 t\u1ea1o ra hi\u1ec7u qu\u1ea3 t\u01b0\u01a1ng t\u1ef1 \u1edf l\u1edbp b\u00ec, t\u0103ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u00e0 m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p \u0111\u1ec3 b\u1ea3o v\u1ec7 l\u1edbp bi\u1ec3u b\u00ec.<\/p>\n

    Hi\u1ec7u \u1ee9ng k\u00edch th\u01b0\u1edbc \u0111\u1ec9\u1ec3m c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u00f3m t\u1eaft nh\u01b0 sau.<\/p>\n

      \n
    1. K\u00edch th\u01b0\u1edbc \u0111i\u1ec3m c\u00e0ng l\u1edbn th\u00ec \u0111\u1ed9 th\u00e2m nh\u1eadp c\u1ee7a tia laser c\u00e0ng s\u00e2u.<\/li>\n
    2. Khi t\u0103ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m \u1edf c\u00f9ng m\u1ed9t m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng, th\u00ec ph\u1ea3i gi\u1ea3m b\u1edbt m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng.<\/li>\n
    3. Khi \u0111i\u1ec1u tr\u1ecb l\u1edbp b\u00ec, n\u00ean s\u1eed d\u1ee5ng k\u00edch th\u01b0\u1edbc<\/li>\n<\/ol>\n

      \u0111i\u1ec3m l\u1edbn \u0111\u1ec3 b\u1ea3o v\u1ec7 l\u1edbp bi\u1ec3u b\u00ec.<\/p>\n

      Lee et al. \u0111\u00e3 s\u1eed d\u1ee5ng laser Nd: YAG xung d\u00e0i v\u00e0 laser alexandrite xung d\u00e0i v\u00e0 quan s\u00e1t s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 c\u1ee7a bi\u1ec3u b\u00ec v\u00e0 b\u00ec khi k\u00edch th\u01b0\u1edbc v\u1ebft \u0111i\u1ec3m v\u00e0 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng t\u01b0\u01a1ng \u1ee9ng l\u00e0 5, 8, 10 mm v\u00e0 26, 30, 36 J\/cm2<\/sup> [24]. K\u1ebft qu\u1ea3 cho th\u1ea5y r\u1eb1ng s\u1ef1 ch\u00eanh l\u1ec7ch nhi\u1ec7t \u0111\u1ed9 bi\u1ec3u b\u00ec kh\u00f4ng l\u1edbn v\u1edbi s\u1ef1 thay \u0111\u1ed5i k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m, nh\u01b0ng nhi\u1ec7t \u0111\u1ed9 bi\u1ec3u b\u00ec t\u0103ng khi t\u0103ng m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng. M\u1eb7t kh\u00e1c, \u1edf l\u1edbp b\u00ec c\u0169ng nh\u01b0 \u1edf l\u1edbp bi\u1ec3u b\u00ec, m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u00e0ng cao th\u00ec nhi\u1ec7t \u0111\u1ed9 c\u1ee7a l\u1edbp b\u00ec c\u00e0ng cao. Nh\u01b0ng ng\u01b0\u1eddi ta quan s\u00e1t th\u1ea5y r\u1eb1ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m c\u00e0ng l\u1edbn so v\u1edbi m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng th\u00ec nhi\u1ec7t \u0111\u1ed9 c\u00e0ng cao. \u0110i\u1ec1u n\u00e0y ph\u00f9 h\u1ee3p v\u1edbi hi\u1ec7u \u1ee9ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 tr\u01b0\u1edbc \u0111\u00f3.<\/p>\n

      V\u1eady, hi\u1ec7u \u1ee9ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho nh\u1eefng lo\u1ea1i \u0111i\u1ec1u tr\u1ecb n\u00e0o? Hi\u1ec7u \u1ee9ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111i\u1ec1u tr\u1ecb c\u00e1c m\u1ee5c ti\u00eau n\u1eb1m trong l\u1edbp b\u00ec. V\u00ed d\u1ee5, k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn \u0111\u01b0\u1ee3c khuy\u1ebfn kh\u00edch cho \u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u, tri\u1ec7t l\u00f4ng, tr\u1ebb h\u00f3a kh\u00f4ng x\u00e2m l\u1ea5n, t\u1ed5n th\u01b0\u01a1ng s\u1eafc t\u1ed1 l\u1edbp b\u00ec,… Trong s\u1ed1 n\u00e0y, ch\u00fang t\u00f4i s\u1ebd \u0111\u00e1nh gi\u00e1 hi\u1ec7u \u1ee9ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng nh\u01b0 th\u1ebf n\u00e0o khi th\u1ef1c hi\u1ec7n x\u00f3a x\u0103m.<\/p>\n

      C\u00f3 r\u1ea5t nhi\u1ec1u th\u00e1ch th\u1ee9c trong vi\u1ec7c x\u00f3a h\u00ecnh x\u0103m b\u1eb1ng laser nh\u01b0ng ch\u00fang ta h\u00e3y xem x\u00e9t m\u1ed9t s\u1ed1 v\u1ea5n \u0111\u1ec1. \u0110\u1ea7u ti\u00ean, tia laser ph\u1ea3i x\u00e2m nh\u1eadp s\u00e2u nh\u1ea5t c\u00f3 th\u1ec3 v\u00ec s\u1eafc t\u1ed1 h\u00ecnh x\u0103m c\u00f3 th\u1ec3 n\u1eb1m \u1edf l\u1edbp r\u1ea5t s\u00e2u c\u1ee7a l\u1edbp b\u00ec. Th\u1ee9 hai, khi h\u00ecnh x\u0103m \u0111\u01b0\u1ee3c x\u0103m l\u1ea1i hai l\u1ea7n ho\u1eb7c ba l\u1ea7n, b\u00f3ng n\u01b0\u1edbc ho\u1eb7c s\u1eb9o c\u00f3 th\u1ec3 x\u1ea3y ra ngay c\u1ea3 khi v\u1ebft x\u0103m nh\u1eb9. Th\u1ee9 ba, c\u00f3 th\u1ec3 x\u1ea3y ra hi\u1ec7n t\u01b0\u1ee3ng s\u1eadm m\u00e0u ngh\u1ecbch l\u00fd. S\u1eadm m\u00e0u ngh\u1ecbch l\u00fd d\u00f9ng \u0111\u1ec3 ch\u1ec9 hi\u1ec7n t\u01b0\u1ee3ng c\u00e1c s\u1eafc t\u1ed1 h\u00ecnh x\u0103m m\u00e0u tr\u1eafng, h\u1ed3ng \u0111\u00e0o, h\u1ed3ng, \u0111\u1ecf chuy\u1ec3n th\u00e0nh m\u00e0u \u0111en khi \u0111\u01b0\u1ee3c \u0111i\u1ec1u tr\u1ecb b\u1eb1ng laser, g\u00e2y kh\u00f3 kh\u0103n cho vi\u1ec7c \u0111i\u1ec1u tr\u1ecb v\u00e0 t\u0103ng s\u1ed1 l\u1ea7n \u0111i\u1ec1u tr\u1ecb [3]. \u0110i\u1ec1u n\u00e0y \u0111\u01b0\u1ee3c bi\u1ebft l\u00e0 x\u1ea3y ra th\u01b0\u1eddng xuy\u00ean trong c\u00e1c h\u00ecnh x\u0103m b\u00e1n v\u0129nh vi\u1ec5n, do s\u1ef1 thay \u0111\u1ed5i h\u00f3a h\u1ecdc t\u1eeb oxit s\u1eaft m\u00e0u \u0111\u1ecf (Fe2O3) sang oxit s\u1eaft \u0111en (FeO). Ngo\u00e0i ra, titanium dioxide, \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho c\u00e1c h\u00ecnh x\u0103m m\u00e0u tr\u1eafng ho\u1eb7c m\u00e0u s\u00e1ng, c\u0169ng \u0111\u01b0\u1ee3c bi\u1ebft \u0111\u1ebfn l\u00e0 nguy\u00ean nh\u00e2n. Beute et al. t\u00ecm th\u1ea5y c\u00e1c hi\u1ec7n t\u01b0\u1ee3ng sau \u0111\u00e2y trong qu\u00e1 tr\u00ecnh \u0111i\u1ec1u tr\u1ecb h\u00ecnh x\u0103m m\u00e0u xanh lam, xanh l\u1ee5c v\u00e0 \u0111\u1ecf b\u1eb1ng laser Q-switched 532 nm [25]. Ngh\u1ecbch l\u00fd s\u1eadm m\u00e0u xu\u1ea5t hi\u1ec7n \u1edf trung t\u00e2m c\u1ee7a chum tia trong khi h\u00ecnh x\u0103m b\u1ecb x\u00f3a \u1edf b\u00ean ngo\u00e0i c\u1ee7a chum tia. N\u0103ng l\u01b0\u1ee3ng y\u1ebfu \u1edf b\u00ean ngo\u00e0i chum tia do t\u00e1n x\u1ea1 v\u00e0 ch\u00f9m tia Gaussian. Do \u0111\u00f3, \u0111i\u1ec1u tr\u1ecb x\u00f3a h\u00ecnh x\u0103m b\u1eb1ng n\u0103ng l\u01b0\u1ee3ng th\u1ea5p c\u00f3 th\u1ec3 s\u1ebd \u00edt x\u1ea3y ra hi\u1ec7n t\u01b0\u1ee3ng s\u1eadm m\u00e0u ngh\u1ecbch l\u00fd h\u01a1n.<\/p>\n

      C\u00e2n nh\u1eafc 3 \u0111i\u1ec3m n\u00eau tr\u00ean v\u1edbi hi\u1ec7u \u1ee9ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m, trong x\u00f3a x\u0103m b\u1eb1ng laser, c\u1ea7n \u0111i\u1ec1u tr\u1ecb v\u00f9ng da v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn \u0111\u1ec3 lo\u1ea1i b\u1ecf c\u00e1c s\u1eafc t\u1ed1 h\u00ecnh x\u0103m s\u00e2u v\u00e0 b\u1ea3o v\u1ec7 l\u1edbp th\u01b0\u1ee3ng b\u00ec. N\u0103ng l\u01b0\u1ee3ng th\u1ea5p n\u00ean \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng tr\u01b0\u1edbc ti\u00ean \u0111\u1ec3 gi\u1eef cho da an to\u00e0n kh\u1ecfi c\u00e1c h\u00ecnh x\u0103m ch\u1ed3ng l\u1ea5p ho\u1eb7c hi\u1ec7n t\u01b0\u1ee3ng s\u1eadm m\u00e0u ngh\u1ecbch l\u00fd. V\u00e0 sau \u0111\u00f3, n\u0103ng l\u01b0\u1ee3ng n\u00ean \u0111\u01b0\u1ee3c t\u0103ng t\u1eeb t\u1eeb. K\u1ebft lu\u1eadn, k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u1edbn ph\u1ea3i \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng tr\u01b0\u1edbc ti\u00ean v\u00e0 n\u0103ng l\u01b0\u1ee3ng ph\u1ea3i \u0111\u01b0\u1ee3c t\u0103ng tu\u1ea7n t\u1ef1 t\u1eeb m\u1ee9c n\u0103ng l\u01b0\u1ee3ng th\u1ea5p [1].<\/p>\n

      C\u1ee5 th\u1ec3, t\u00f4i \u0111i\u1ec1u tr\u1ecb h\u00ecnh x\u0103m nh\u01b0 sau: ch\u1ecdn \u0111i\u1ec3m k\u1ebft th\u00fac l\u00e2m s\u00e0ng l\u00e0 \u201cl\u00e0m tr\u1eafng ngay l\u1eadp t\u1ee9c v\u1edbi ch\u1ea5m xu\u1ea5t huy\u1ebft r\u00f5 r\u1ec7t\u201d v\u00e0 s\u1eed d\u1ee5ng tia laser Q-switched Nd: YAG 1064-nm v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 8 mm, 2,6 J\/cm2<\/sup>. L\u00fd do t\u00f4i s\u1eed d\u1ee5ng 2,6 J\/cm2<\/sup> l\u00e0 v\u00ec laser Q-switched Nd: YAG c\u1ee7a t\u00f4i c\u00f3 n\u0103ng l\u01b0\u1ee3ng t\u1ed1i \u0111a l\u00e0 2,6 J\/cm2<\/sup> t\u1ea1i k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 8 mm. Ch\u1ec9 chi\u1ebfu tia m\u1ed9t l\u1ea7n v\u00e0 n\u1ebfu \u0111i\u1ec3m k\u1ebft th\u00fac l\u00e2m s\u00e0ng kh\u00f4ng x\u1ea3y ra, h\u00e3y gi\u1ea3m k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m xu\u1ed1ng 7 mm v\u00e0 n\u0103ng l\u01b0\u1ee3ng t\u0103ng l\u00ean m\u1ee9c t\u1ed1i \u0111a l\u00e0 3,4 J\/cm2<\/sup>. Sau \u0111\u00f3, n\u0103ng l\u01b0\u1ee3ng \u0111\u01b0\u1ee3c t\u0103ng l\u00ean b\u1eb1ng c\u00e1ch gi\u1ea3m k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m: k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 6 mm, 4,6 J\/cm2<\/sup> \u2192 k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 5 mm, 5,5 J\/cm2<\/sup> \u2192 k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 5 mm, 6,6 J\/cm2<\/sup>. Khi th\u1ea5y \u0111\u01b0\u1ee3c \u0111i\u1ec3m k\u1ebft th\u00fac l\u00e2m s\u00e0ng, to\u00e0n b\u1ed9 h\u00ecnh x\u0103m x\u0103m \u0111\u01b0\u1ee3c x\u1eed l\u00fd b\u1eb1ng n\u0103ng l\u01b0\u1ee3ng t\u01b0\u01a1ng \u1ee9ng. Trong l\u1ea7n \u0111i\u1ec1u tr\u1ecb ti\u1ebfp theo, n\u0103ng l\u01b0\u1ee3ng t\u01b0\u01a1ng t\u1ef1 \u0111\u01b0\u1ee3c ki\u1ec3m tra l\u1ea1i, v\u00e0 n\u1ebfu kh\u00f4ng th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c \u0111i\u1ec3m k\u1ebft th\u00fac l\u00e2m s\u00e0ng, th\u00ec k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m s\u1ebd gi\u1ea3m v\u00e0 n\u0103ng l\u01b0\u1ee3ng \u0111\u01b0\u1ee3c t\u0103ng l\u00ean. L\u00fd do c\u1ee7a vi\u1ec7c gi\u1ea3m d\u1ea7n k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u00e0 v\u00ec c\u00f3 s\u1ef1 gi\u1edbi h\u1ea1n v\u1ec1 n\u0103ng l\u01b0\u1ee3ng c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c n\u00e2ng l\u00ean \u1edf m\u1ed9t k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m nh\u1ea5t \u0111\u1ecbnh.<\/p>\n

      M\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng<\/h2>\n

      M\u1ee5c ti\u00eau c\u1ee7a \u0111i\u1ec1u tr\u1ecb b\u1eb1ng laser l\u00e0 t\u0103ng nhi\u1ec7t \u0111\u1ed9 m\u1ed9t c\u00e1ch ch\u1ecdn l\u1ecdc c\u1ee7a m\u1ed9t th\u1ec3 nhi\u1ec5m s\u1eafc c\u1ee5 th\u1ec3 v\u00e0 cu\u1ed1i c\u00f9ng g\u00e2y ra s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 \u0111\u00edch.<\/p>\n

      M\u1ed1i quan h\u1ec7 gi\u1eefa m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng v\u00e0 \u0111\u1ed9 d\u00e0i xung<\/h3>\n
      \"3.6.1M\u1ed1i
      3.6.1 M\u1ed1i quan h\u1ec7 gi\u1eefa m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng v\u00e0 \u0111\u1ed9 d\u00e0i xung<\/figcaption><\/figure>\n

      \u00a0<\/strong><\/p>\n

      \u0394T<\/em>: bi\u1ebfn \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u1ee5c ti\u00eau<\/p>\n

      \u00b5<\/em>a<\/em>: h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5<\/p>\n

      F<\/em>z<\/em>: m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ee5c b\u1ed9 d\u01b0\u1edbi b\u1ec1 m\u1eb7t<\/p>\n

      \u03c1<\/em>: m\u1eadt \u0111\u1ed9<\/p>\n

      c<\/em>: nhi\u1ec7t dung ri\u00eang<\/p>\n

      g<\/em>: h\u1ec7 s\u1ed1 h\u00ecnh h\u1ecdc (m\u1ed9t cho m\u1eb7t ph\u1eb3ng, hai cho h\u00ecnh tr\u1ee5 v\u00e0 ba cho h\u00ecnh c\u1ea7u)<\/p>\n

      \u03c4<\/em>p<\/em>: \u0111\u1ed9 d\u00e0i xung laser<\/p>\n

      \u03c4<\/em>r<\/em>: th\u1eddi gian gi\u00e3n nhi\u1ec7t c\u1ee7a m\u1ee5c ti\u00eau (TRT)<\/p>\n

      Ph\u01b0\u01a1ng tr\u00ecnh tr\u00ean \u00e1p d\u1ee5ng cho nhi\u1ec7t \u0111\u1ed9. T\u1eeb ph\u01b0\u01a1ng tr\u00ecnh tr\u00ean, ch\u00fang ta c\u00f3 th\u1ec3 th\u1ea5y r\u1eb1ng \u201cchi\u1ebfu x\u1ea1 v\u00f9ng s\u1eadm m\u00e0u y\u1ebfu, v\u00f9ng s\u00e1ng m\u00e0u m\u1ea1nh\u201d \u0111\u01b0\u1ee3c \u0111\u1ec1 c\u1eadp tr\u01b0\u1edbc \u0111\u00e2y l\u00e0 \u0111\u00fang. N\u00f3i c\u00e1ch kh\u00e1c, n\u1ebfu h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 (\u00b5a) cao, th\u00ec ph\u1ea3i chi\u1ebfu tia m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng th\u1ea5p (Fz) \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u1ee9c t\u0103ng nhi\u1ec7t \u0111\u1ed9 c\u1ee7a<\/p>\n

      m\u1ee5c ti\u00eau mong mu\u1ed1n. Ng\u01b0\u1ee3c l\u1ea1i, n\u1ebfu h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 th\u1ea5p, th\u00ec ph\u1ea3i chi\u1ebfu tia m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng cao \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u1ee9c t\u0103ng nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u1ee5c ti\u00eau mong mu\u1ed1n.<\/p>\n

      C\u00f2n \u0111\u1ed9 d\u00e0i xung? M\u1ed1i quan h\u1ec7 gi\u1eefa m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng v\u00e0 \u0111\u1ed9 d\u00e0i xung l\u00e0 g\u00ec? Ph\u01b0\u01a1ng tr\u00ecnh tr\u00ean cho th\u1ea5y \u0111\u1ed9 d\u00e0i xung (\u03c4p). Tuy nhi\u00ean, v\u00ec n\u00f3 l\u00e0 m\u1ed9t ph\u1ea7n c\u1ee7a m\u1eabu s\u1ed1 d\u01b0\u1edbi h\u00e0m s\u1ed1 m\u0169, n\u00ean tho\u1ea1t nh\u00ecn r\u1ea5t kh\u00f3 \u0111\u1ec3 bi\u1ebft \u0111\u01b0\u1ee3c m\u1ed1i t\u01b0\u01a1ng quan. Nh\u01b0ng n\u1ebfu \u0111\u1eb7t c\u00e1c con s\u1ed1 v\u00e0o ph\u01b0\u01a1ng tr\u00ecnh, b\u1ea1n c\u00f3 th\u1ec3 th\u1ea5y r\u1eb1ng \u0111\u1ed9 d\u00e0i xung v\u00e0 nhi\u1ec7t \u0111\u1ed9 c\u00f3 li\u00ean quan ngh\u1ecbch v\u1edbi nhau. Ng\u01b0\u1ee3c l\u1ea1i, m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng v\u00e0 \u0111\u1ed9 d\u00e0i xung t\u1ef7 l\u1ec7 thu\u1eadn v\u1edbi nhau n\u1ebfu nhi\u1ec7t \u0111\u1ed9 nh\u01b0 nhau.<\/p>\n

      Trafeli et al. \u0111\u00e3 s\u1eed d\u1ee5ng laser alexandrite xung d\u00e0i 755 nm \u0111\u1ec3 \u0111o m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ee7a c\u00e1c \u0111i\u1ec3m k\u1ebft th\u00fac l\u00e2m s\u00e0ng gi\u1ed1ng nhau, t\u1ee9c l\u00e0 c\u00f9ng nhi\u1ec7t \u0111\u1ed9, t\u00f9y thu\u1ed9c v\u00e0o \u0111\u1ed9 d\u00e0i xung [26]. D\u1ef1a tr\u00ean k\u1ebft qu\u1ea3 v\u00e0 s\u1ed1 li\u1ec7u c\u1ee7a b\u00e0i b\u00e1o n\u00e0y, c\u00f3 th\u1ec3 r\u00fat ra hai k\u1ebft lu\u1eadn. \u0110\u1ea7u ti\u00ean, \u0111\u1ed9 d\u00e0i xung v\u00e0 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng t\u1ef7 l\u1ec7 thu\u1eadn v\u1edbi nhau. N\u00f3i c\u00e1ch kh\u00e1c, \u0111\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c hi\u1ec7u qu\u1ea3 t\u01b0\u01a1ng t\u1ef1, n\u00ean t\u0103ng m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng \u0111\u1ec3 t\u0103ng \u0111\u1ed9 d\u00e0i xung v\u00e0 gi\u1ea3m m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng \u0111\u1ec3 r\u00fat ng\u1eafn \u0111\u1ed9 d\u00e0i xung. Th\u1ee9 hai, \u0111\u1ed9 d\u00e0i xung v\u00e0 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng t\u1ef7 l\u1ec7 thu\u1eadn v\u1edbi nhau, nh\u01b0ng kh\u00f4ng c\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t \u0111\u00e1ng k\u1ec3 v\u1ec1 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng. Do \u0111\u00f3, n\u1ebfu c\u00f3 m\u1ed9t \u0111i\u1ec3m k\u1ebft th\u00fac l\u00e2m s\u00e0ng th\u00edch h\u1ee3p v\u1edbi m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ee5 th\u1ec3 t\u1ea1i m\u1ed9t \u0111\u1ed9 d\u00e0i xung nh\u1ea5t \u0111\u1ecbnh, th\u00ec kh\u00f4ng c\u1ea7n ph\u1ea3i \u0111i\u1ec1u ch\u1ec9nh m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng cho d\u00f9 \u0111\u1ed9 d\u00e0i xung gi\u1ea3m hay t\u0103ng. T\u1ea5t nhi\u00ean, \u0111\u1ec3 th\u1ef1c hi\u1ec7n th\u1ee7 thu\u1eadt m\u1ed9t c\u00e1ch an to\u00e0n, t\u1ed1t h\u01a1n n\u00ean gi\u1ea3m b\u1edbt m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng khi gi\u1ea3m \u0111\u1ed9 d\u00e0i xung.<\/p>\n

      L\u00e0m m\u00e1t bi\u1ec3u b\u00ec trong \u0111i\u1ec1u tr\u1ecb s\u1eafc t\u1ed1 bi\u1ec3u b\u00ec<\/h3>\n

      M\u1ed9t \u0111i\u1ec3m c\u1ea7n nh\u1edb trong b\u00e0i n\u00e0y l\u00e0 t\u1ed1t h\u01a1n h\u1ebft l\u00e0 kh\u00f4ng n\u00ean l\u00e0m m\u00e1t l\u1edbp bi\u1ec3u b\u00ec trong qu\u00e1 tr\u00ecnh \u0111i\u1ec1u tr\u1ecb bi\u1ec3u b\u00ec.<\/p>\n

      B\u1ea3ng 3.3 <\/strong>Gi\u00e1 tr\u1ecb gi\u1ea3 thi\u1ebft n\u1ebfu gi\u1ea3 s\u1eed nhi\u1ec7t \u0111\u1ed9 da b\u00ecnh th\u01b0\u1eddng l\u00e0 35\u00b0C, ch\u00eanh l\u1ec7ch nhi\u1ec7t \u0111\u1ed9 do l\u00e0m m\u00e1t bi\u1ec3u b\u00ec l\u00e0 -10\u00b0C v\u00e0 nhi\u1ec7t \u0111\u1ed9 m\u1ee5c ti\u00eau l\u00e0 75\u00b0C, v\u00e0 t\u00edch c\u1ee7a m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng v\u00e0 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 l\u00e0 s\u1ef1 ch\u00eanh l\u1ec7ch nhi\u1ec7t \u0111\u1ed9 (\u0394T )<\/p>\n\n\n\n\n\n
      M\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng<\/td>\nM\u00f4 \u0111\u00edch (\u00b5<\/em>a <\/em>= 10)<\/td>\nM\u00f4 b\u00ecnh th\u01b0\u1eddng (\u00b5<\/em>a <\/em>= 1)<\/td>\n<\/tr>\n
      5 J\/cm2<\/sup>\u00a0\u00a0\u00a0\u00a0 (v\u1edbi DCD)<\/td>\n(5 \u00d7 10) + 35 \u2212 10 = 75\u00b0C<\/td>\n(5 \u00d7 1) + 35 \u2212 10 = 30\u00b0C<\/td>\n<\/tr>\n
      4 J\/cm2<\/sup> (kh\u00f4ng DCD)<\/td>\n(4 \u00d7 10) + 35 = 75\u00b0C<\/td>\n(4 \u00d7 1) + 35 = 39\u00b0C<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      (m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng \u00d7 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5) + nhi\u1ec7t \u0111\u1ed9 b\u00ecnh th\u01b0\u1eddng – nhi\u1ec7t \u0111\u1ed9 l\u00e0m m\u00e1t = nhi\u1ec7t \u0111\u1ed9 cu\u1ed1i c\u00f9ng<\/p>\n

      B\u1ea3ng 3.3 <\/em>l\u00e0 b\u1ea3ng \u0111\u01b0\u1ee3c t\u00ednh to\u00e1n b\u1eb1ng c\u00e1ch thi\u1ebft l\u1eadp c\u00e1c gi\u00e1 tr\u1ecb \u1ea3o. Gi\u1ea3 s\u1eed r\u1eb1ng nhi\u1ec7t \u0111\u1ed9 b\u00ecnh th\u01b0\u1eddng c\u1ee7a da l\u00e0 35\u00b0C, ch\u00eanh l\u1ec7ch nhi\u1ec7t \u0111\u1ed9 do l\u00e0m m\u00e1t bi\u1ec3u b\u00ec l\u00e0 -10\u00b0C v\u00e0 nhi\u1ec7t \u0111\u1ed9 m\u1ee5c ti\u00eau l\u00e0 75\u00b0C, v\u00e0 t\u00edch c\u1ee7a m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng v\u00e0 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 l\u00e0 s\u1ef1 ch\u00eanh l\u1ec7ch nhi\u1ec7t \u0111\u1ed9 (\u0394T), nhi\u1ec7t \u0111\u1ed9 cu\u1ed1i c\u00f9ng l\u00e0 [(m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng \u00d7 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5) + nhi\u1ec7t \u0111\u1ed9 th\u01b0\u1eddng – nhi\u1ec7t \u0111\u1ed9 l\u00e0m m\u00e1t = nhi\u1ec7t \u0111\u1ed9 cu\u1ed1i].<\/p>\n

      L\u00e0m m\u00e1t bi\u1ec3u b\u00ec s\u1ebd l\u00e0m gi\u1ea3m nhi\u1ec7t \u0111\u1ed9 b\u1eb1ng c\u00f9ng m\u1ed9t s\u1ef1 ch\u00eanh l\u1ec7ch nhi\u1ec7t \u0111\u1ed9 (\u0394T) cho c\u1ea3 t\u1ed5n th\u01b0\u01a1ng s\u1eafc t\u1ed1 bi\u1ec3u b\u00ec v\u00e0 m\u00f4 b\u00ecnh th\u01b0\u1eddng xung quanh. C\u00e1c m\u00f4 b\u00ecnh th\u01b0\u1eddng c\u00f3 nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n b\u00ecnh th\u01b0\u1eddng, do \u0111\u00f3 kh\u00f4ng c\u00f3 kh\u1ea3 n\u0103ng x\u1ea3y ra t\u00e1c d\u1ee5ng ph\u1ee5, nh\u01b0ng c\u00e1c t\u1ed5n th\u01b0\u01a1ng s\u1eafc t\u1ed1 c\u0169ng s\u1ebd c\u00f3 nhi\u1ec7t \u0111\u1ed9 th\u1ea5p v\u00e0 kh\u00f4ng th\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c hi\u1ec7u qu\u1ea3 mong mu\u1ed1n. \u0110\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c hi\u1ec7u qu\u1ea3, c\u1ea7n ph\u1ea3i t\u0103ng m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng (5 J\/cm2<\/sup>) khi l\u00e0m m\u00e1t bi\u1ec3u b\u00ec, \u0111\u1ec3 nhi\u1ec7t \u0111\u1ed9 c\u1ee7a t\u1ed5n th\u01b0\u01a1ng s\u1eafc t\u1ed1 bi\u1ec3u b\u00ec cao h\u01a1n (75\u00b0C), v\u00e0 c\u00f3 hi\u1ec7u qu\u1ea3 mong mu\u1ed1n. Nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 xung quanh th\u1ea5p h\u01a1n nhi\u1ec7t \u0111\u1ed9 b\u00ecnh th\u01b0\u1eddng (30\u00b0C), d\u1eabn \u0111\u1ebfn an to\u00e0n. M\u1eb7t kh\u00e1c, khi kh\u00f4ng l\u00e0m l\u1ea1nh bi\u1ec3u b\u00ec, nhi\u1ec7t \u0111\u1ed9 c\u1ee7a t\u1ed5n th\u01b0\u01a1ng s\u1eafc t\u1ed1 bi\u1ec3u b\u00ec gi\u1ed1ng nh\u01b0 c\u00f3 l\u00e0m m\u00e1t bi\u1ec3u b\u00ec, nh\u01b0ng nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 xung quanh cao h\u01a1n tr\u01b0\u1eddng h\u1ee3p c\u00f3 l\u00e0m m\u00e1t bi\u1ec3u b\u00ec (39\u00b0C).<\/p>\n

      Do \u0111\u00f3, m\u1eb7c d\u00f9 k\u1ebft qu\u1ea3 l\u00e0 nh\u01b0 nhau, v\u00ec nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 xung quanh gi\u1ea3m khi l\u00e0m m\u00e1t bi\u1ec3u b\u00ec v\u00e0 nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 xung quanh t\u0103ng khi kh\u00f4ng l\u00e0m m\u00e1t bi\u1ec3u b\u00ec, n\u00ean vi\u1ec7c l\u00e0m m\u00e1t bi\u1ec3u b\u00ec d\u01b0\u1eddng nh\u01b0 l\u00e0 \u0111\u00e1ng mong \u0111\u1ee3i. Tuy nhi\u00ean, c\u1ea3 30\u00b0C v\u00e0 39\u00b0C \u0111\u1ec1u kh\u00f4ng g\u00e2y ra v\u1ea5n \u0111\u1ec1 cho da. M\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng l\u00e0 v\u1ea5n \u0111\u1ec1 c\u00f2n h\u01a1n nhi\u1ec7t \u0111\u1ed9. Trong B\u1ea3ng 3.3<\/em>, s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng d\u01b0\u1eddng nh\u01b0 l\u00e0 nh\u1ecf, nh\u01b0ng n\u1ebfu m\u00e1y laser l\u00e0 c\u00f4ng su\u1ea5t th\u1ea5p kh\u00f4ng th\u1ec3 t\u0103ng m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng qu\u00e1 4 J\/cm2<\/sup>, th\u00ec \u0111\u1ed9 d\u00e0i xung ph\u1ea3i \u0111\u01b0\u1ee3c t\u0103ng l\u00ean \u0111\u1ec3 t\u1ea1o ra 5 J\/cm2<\/sup>. V\u00e0 b\u1edfi v\u00ec \u0111\u1ed9 d\u00e0i xung kh\u00f4ng th\u1ec3 gi\u1ea3m, c\u00e1c m\u00f4 nh\u1ecf r\u1ea5t kh\u00f3 \u0111i\u1ec1u tr\u1ecb. Do \u0111\u00f3, l\u00e0m m\u00e1t bi\u1ec3u b\u00ec kh\u00f4ng c\u00f3 \u00fd ngh\u0129a trong c\u00e1c t\u1ed5n th\u01b0\u01a1ng s\u1eafc t\u1ed1 bi\u1ec3u b\u00ec v\u00ec l\u00e0m m\u00e1t bi\u1ec3u b\u00ec c\u00f3 nhi\u1ec1u nh\u01b0\u1ee3c \u0111i\u1ec3m h\u01a1n l\u00e0 \u01b0u \u0111i\u1ec3m.<\/p>\n

      Ph\u01b0\u01a1ng tr\u00ecnh Arrhenius<\/h3>\n

      Khi photon c\u1ee7a laser cu\u1ed1i c\u00f9ng g\u1eb7p \u0111\u01b0\u1ee3c th\u1ec3 nhi\u1ec5m s\u1eafc, nhi\u1ec7t \u0111\u1ed9 t\u0103ng l\u00ean. Nh\u01b0 trong \u201cCh\u01b0\u01a1ng 2\u201d, khi nhi\u1ec7t \u0111\u1ed9 t\u0103ng l\u00ean, c\u00e1c hi\u1ec7n t\u01b0\u1ee3ng nh\u01b0 plasma, s\u00f3ng xung k\u00edch, b\u00f3ng kh\u00ed v\u00e0 ph\u1ea3n l\u1ef1c x\u1ea3y ra trong hi\u1ec7u \u1ee9ng quang c\u01a1. Trong hi\u1ec7u \u1ee9ng quang nhi\u1ec7t, x\u1ea3y ra \u0111\u00f4ng t\u1ee5, h\u00f3a h\u01a1i, cacbon h\u00f3a v\u00e0 n\u00f3ng ch\u1ea3y. Trong s\u1ed1 c\u00e1c hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y, ph\u01b0\u01a1ng tr\u00ecnh Arrhenius \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng d\u01b0\u1edbi 100\u00b0C, kh\u00f4ng x\u1ea3y ra hi\u1ec7n t\u01b0\u1ee3ng h\u00f3a h\u01a1i. Ti\u1ebfp theo, h\u00e3y xem x\u00e9t c\u00f4ng th\u1ee9c Arrhenius.<\/p>\n

      2N2O5 (g) \u2192 4NO2 (g) + O2 (g)<\/p>\n

      T\u1ed1c \u0111\u1ed9 ph\u1ea3n \u1ee9ng= k <\/em>[N2O5]n<\/sup><\/p>\n

      k<\/em>: h\u1eb1ng s\u1ed1 t\u1ed1c \u0111\u1ed9.<\/p>\n

      Khi N2O2 \u0111\u01b0\u1ee3c chuy\u1ec3n th\u00e0nh NO2 v\u00e0 O2, t\u1ed1c \u0111\u1ed9 thay \u0111\u1ed5i t\u1ef7 l\u1ec7 v\u1edbi n\u1ed3ng \u0111\u1ed9 c\u1ee7a N2O2 v\u00e0 h\u1eb1ng s\u1ed1 t\u1ed1c \u0111\u1ed9 (k<\/em>). N\u00f3i c\u00e1ch kh\u00e1c, t\u1ed1c \u0111\u1ed9 thay \u0111\u1ed5i c\u1ee7a m\u1ed9t ch\u1ea5t cao h\u01a1n \u1edf n\u1ed3ng \u0111\u1ed9 cao h\u01a1n. M\u1ed9t bi\u1ebfn s\u1ed1 kh\u00e1c v\u1edbi n\u1ed3ng \u0111\u1ed9 c\u1ee7a m\u1ed9t ch\u1ea5t \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 m\u1ed9t h\u1eb1ng s\u1ed1 t\u1ed1c \u0111\u1ed9 (k<\/em>). H\u1eb1ng s\u1ed1 t\u1ed1c \u0111\u1ed9 n\u00e0y kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o n\u1ed3ng \u0111\u1ed9 v\u00e0 c\u00e1c nh\u00e0 v\u1eadt l\u00fd nh\u1eadn th\u1ea5y r\u1eb1ng n\u00f3 thay \u0111\u1ed5i theo nhi\u1ec7t \u0111\u1ed9 c\u1ee7a v\u1eadt li\u1ec7u v\u00e0 ch\u1ea5t x\u00fac t\u00e1c. V\u00ec ch\u00fang t\u00f4i kh\u00f4ng s\u1eed d\u1ee5ng ch\u1ea5t x\u00fac t\u00e1c [27], h\u00e3y t\u1eadp trung v\u00e0o nhi\u1ec7t \u0111\u1ed9. T\u00ednh to\u00e1n v\u1eadt l\u00fd h\u1eb1ng s\u1ed1 t\u1ed1c \u0111\u1ed9, ph\u01b0\u01a1ng tr\u00ecnh \u0111\u01b0\u1ee3c bi\u1ec3u th\u1ecb nh\u01b0 sau:<\/p>\n

      K <\/em>= Ae-Ea\/RT<\/p>\n

      k<\/em>: h\u1eb1ng s\u1ed1 t\u1ed1c \u0111\u1ed9 c\u1ee7a ph\u1ea3n \u1ee9ng<\/p>\n

      A<\/em>: h\u1eb1ng s\u1ed1, ph\u1ee5 thu\u1ed9c v\u00e0o ph\u1ea3n \u1ee9ng<\/p>\n

      E<\/em>a<\/em>: n\u0103ng l\u01b0\u1ee3ng ho\u1ea1t h\u00f3a<\/p>\n

      R<\/em>: h\u1eb1ng s\u1ed1 mol kh\u00ed<\/p>\n

      T<\/em>: nhi\u1ec7t \u0111\u1ed9<\/p>\n

      V\u00ec ph\u01b0\u01a1ng tr\u00ecnh tr\u00ean r\u1ea5t kh\u00f3 hi\u1ec3u khi \u0111\u01b0\u1ee3c v\u1ebd d\u01b0\u1edbi d\u1ea1ng \u0111\u1ed3 th\u1ecb, n\u00ean n\u00f3 \u0111\u01b0\u1ee3c bi\u1ec3u di\u1ec5n b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng h\u00e0m logarit v\u00e0 ph\u01b0\u01a1ng tr\u00ecnh nh\u01b0 \u201cy = ax + b\u201d. C\u00f4ng th\u1ee9c Arrhenius ban \u0111\u1ea7u l\u00e0 c\u00f4ng th\u1ee9c x\u00e1c \u0111\u1ecbnh n\u0103ng l\u01b0\u1ee3ng ho\u1ea1t h\u00f3a (E) t\u01b0\u01a1ng \u1ee9ng v\u1edbi h\u1ec7 s\u1ed1 g\u00f3c (a) v\u00e0 h\u1ec7 s\u1ed1 t\u1ea7n s\u1ed1 (A) t\u01b0\u01a1ng \u1ee9ng v\u1edbi giao \u0111i\u1ec3m tr\u1ee5c y (b) b\u1eb1ng c\u00e1ch \u0111o c\u00e1c h\u1eb1ng s\u1ed1 t\u1ed1c \u0111\u1ed9 theo hai nhi\u1ec7t \u0111\u1ed9 (K\u00edch ho\u1ea1t c\u00e1c y\u1ebfu t\u1ed1 n\u0103ng l\u01b0\u1ee3ng v\u00e0 t\u1ea7n s\u1ed1 \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 h\u1eb1ng s\u1ed1 Arrhenius [19]).<\/p>\n

      \"\u1ea2nh
      \u1ea2nh h\u01b0\u1edfng c\u1ee7a nhi\u1ec7t \u0111\u1ed9 v\u00e0 th\u1eddi gian ti\u1ebfp x\u00fac \u0111\u1ebfn s\u1ef1 ph\u00e1 h\u1ee7y kh\u00f4ng th\u1ec3 ph\u1ee5c h\u1ed3i c\u1ee7a c\u00e1c m\u00f4.<\/figcaption><\/figure>\n

      H\u00ecnh 3.12 <\/strong>\u1ea2nh h\u01b0\u1edfng c\u1ee7a nhi\u1ec7t \u0111\u1ed9 v\u00e0 th\u1eddi gian ti\u1ebfp x\u00fac \u0111\u1ebfn s\u1ef1 ph\u00e1 h\u1ee7y kh\u00f4ng th\u1ec3 ph\u1ee5c h\u1ed3i c\u1ee7a c\u00e1c m\u00f4.<\/p>\n

      Tuy nhi\u00ean, v\u00ec ch\u00fang ta ch\u1ec9 c\u1ea7n bi\u1ebft m\u1ed1i quan h\u1ec7 gi\u1eefa nhi\u1ec7t \u0111\u1ed9 v\u00e0 m\u00f4 da, ch\u00fang ta c\u00f3 th\u1ec3 t\u00f3m t\u1eaft \u00fd ngh\u0129a c\u1ee7a c\u00f4ng th\u1ee9c Arrhenius nh\u01b0 sau:<\/p>\n

      Th\u1ee9 nh\u1ea5t, nhi\u1ec7t \u0111\u1ed9 c\u00e0ng cao, t\u1ed1c \u0111\u1ed9 ph\u1ea3n \u1ee9ng c\u00e0ng nhanh. N\u00f3i c\u00e1ch kh\u00e1c, v\u1eadt li\u1ec7u thay \u0111\u1ed5i nhanh \u1edf nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n. Ng\u01b0\u1ee3c l\u1ea1i, v\u1eadt li\u1ec7u thay \u0111\u1ed5i ch\u1eadm \u1edf nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n. Th\u1ee9 hai, c\u00f3 nh\u1eefng c\u00e1i \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 n\u0103ng l\u01b0\u1ee3ng ho\u1ea1t h\u00f3a. N\u00f3i c\u00e1ch kh\u00e1c, n\u1ebfu c\u00f3 m\u1ed9t ng\u01b0\u1ee1ng v\u00e0 ng\u01b0\u1ee1ng n\u00e0y kh\u00f4ng b\u1ecb v\u01b0\u1ee3t qu\u00e1, th\u00ec s\u1ef1 tho\u00e1i h\u00f3a m\u00f4 kh\u00f4ng x\u1ea3y ra. Ch\u00fang ta h\u00e3y xem x\u00e9t k\u1ef9 h\u01a1n hai k\u1ebft lu\u1eadn n\u00e0y.<\/p>\n

      Tr\u01b0\u1edbc ti\u00ean, h\u00e3y t\u00ecm hi\u1ec3u v\u1ec1 nhi\u1ec7t \u0111\u1ed9 v\u00e0 th\u1eddi gian. H\u00ecnh 3.12 <\/em>v\u1ebd bi\u1ec3u \u0111\u1ed3 c\u1ee7a c\u00f4ng th\u1ee9c Arrhenius d\u01b0\u1edbi d\u1ea1ng m\u1ed9t h\u00e0m c\u1ee7a nhi\u1ec7t \u0111\u1ed9 theo th\u1eddi gian, kh\u00f4ng ph\u1ea3i t\u1ed1c \u0111\u1ed9. \u0110\u1ec3 bi\u1ebfn t\u00ednh m\u00f4, kh\u00f4ng ch\u1ec9 nhi\u1ec7t \u0111\u1ed9 m\u00e0 th\u1eddi gian c\u0169ng r\u1ea5t quan tr\u1ecdng. V\u00ed d\u1ee5, s\u1ef1 tho\u00e1i h\u00f3a m\u00f4 x\u1ea3y ra \u1edf h\u01a1n 10 gi\u00e2y \u1edf 57\u00b0C, nh\u01b0ng kh\u00f4ng x\u1ea3y ra \u1edf 5 gi\u00e2y \u1edf 57\u00b0C. Ngo\u00e0i ra, s\u1ef1 tho\u00e1i h\u00f3a m\u00f4 x\u1ea3y ra \u1edf 1 gi\u00e2y \u1edf 65\u00b0C nh\u01b0ng kh\u00f4ng x\u1ea3y ra \u1edf 0,5 gi\u00e2y. Kh\u00f4ng c\u00f3 nhi\u1ec7t \u0111\u1ed9 tuy\u1ec7t \u0111\u1ed1i cho s\u1ef1 tho\u00e1i h\u00f3a ho\u1eb7c \u0111\u00f4ng t\u1ee5 c\u1ee7a m\u00f4. Th\u1eddi gian c\u0169ng nh\u01b0 nhi\u1ec7t \u0111\u1ed9 ph\u1ea3i \u0111\u01b0\u1ee3c xem x\u00e9t. \u0110\u01b0\u1ee3c bi\u1ebft, khi nhi\u1ec7t \u0111\u1ed9 gi\u1ea3m 5\u00b0C th\u00ec th\u1eddi gian y\u00eau c\u1ea7u c\u1ea7n g\u1ea5p m\u01b0\u1eddi l\u1ea7n [1].<\/p>\n

      B\u1edfi v\u00ec nhi\u1ec7t \u0111\u1ed9 thay \u0111\u1ed5i theo th\u1eddi gian, nhi\u1ec7t \u0111\u1ed9 t\u1ea1i \u0111\u00f3 s\u1ef1 tho\u00e1i h\u00f3a m\u00f4 x\u1ea3y ra l\u00e0 50\u2013 70\u00b0C \u1edf m\u1ed9t s\u1ed1 t\u00e0i li\u1ec7u v\u00e0 57\u201365\u00b0C ho\u1eb7c 60\u00b0C \u1edf m\u1ed9t s\u1ed1 t\u00e0i li\u1ec7u kh\u00e1c [16, 29]. \u0110\u1ec3 ng\u0103n ng\u1eeba s\u1ef1 nh\u1ea7m l\u1eabn n\u00e0y, Pearce v\u00e0 Thomsen \u0111\u00e3 \u0111\u1ecbnh ngh\u0129a nhi\u1ec7t \u0111\u1ed9 t\u1edbi h\u1ea1n (Tcrit) l\u00e0 nhi\u1ec7t \u0111\u1ed9 m\u00e0 100% t\u1ed5n h\u1ea1i x\u1ea3y ra trong 1 gi\u00e2y [1]. Nhi\u1ec7t \u0111\u1ed9 t\u1edbi h\u1ea1n c\u1ee7a m\u00f4 ng\u01b0\u1eddi \u0111\u01b0\u1ee3c bi\u1ebft l\u00e0 t\u1eeb 60 \u0111\u1ebfn 85\u00b0C t\u00f9y thu\u1ed9c v\u00e0o c\u00e1c m\u00f4.<\/p>\n

      B\u1ea3ng 3.4 <\/strong>Hai ph\u01b0\u01a1ng ph\u00e1p tr\u1ebb h\u00f3a kh\u00f4ng x\u00e2m l\u1ea5n<\/p>\n\n\n\n\n\n
      Ph\u01b0\u01a1ng ph\u00e1p<\/td>\nTh\u1eddi gian v\u00e0 nhi\u1ec7t \u0111\u1ed9<\/td>\nC\u1eeda s\u1ed5 tr\u1ecb li\u1ec7u<\/td>\nH\u1ea1n ch\u1ebf<\/td>\n<\/tr>\n
      A<\/td>\nTh\u1eddi\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 gian ng\u1eafn v\u00e0 nhi\u1ec7t<\/p>\n

      \u0111\u1ed9 cao<\/td>\n

      		H\u1eb9p<\/td>\n\u0110au, t\u00e1c d\u1ee5ng ph\u1ee5<\/td>\n<\/tr>\n
      B<\/td>\nTh\u1eddi gian d\u00e0i v\u00e0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 nhi\u1ec7t\u00a0\u00a0\u00a0 \u0111\u1ed9<\/p>\n

      th\u1ea5p<\/td>\n

      		R\u1ed9ng<\/td>\nTh\u1eddi gian th\u1ef1c<\/p>\n

      hi\u1ec7n d\u00e0i<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      Theo c\u00f4ng th\u1ee9c Arrhenius, c\u00f3 hai ph\u01b0\u01a1ng ph\u00e1p g\u00e2y ra hi\u1ec7n t\u01b0\u1ee3ng \u0111\u00f4ng t\u1ee5 (B\u1ea3ng 3.4<\/em>). Ph\u01b0\u01a1ng ph\u00e1p th\u1ee9 nh\u1ea5t s\u1eed d\u1ee5ng nhi\u1ec7t \u0111\u1ed9 cao trong th\u1eddi gian ng\u1eafn (A), v\u00e0 ph\u01b0\u01a1ng ph\u00e1p th\u1ee9 hai l\u00e0 s\u1eed d\u1ee5ng nhi\u1ec7t \u0111\u1ed9 th\u1ea5p trong th\u1eddi gian d\u00e0i (B). C\u00e1i n\u00e0o t\u1ed1t h\u01a1n? \u0110i\u1ec1u n\u00e0y s\u1ebd \u0111\u01b0\u1ee3c gi\u1ea3i th\u00edch chi ti\u1ebft trong \u201cCh\u01b0\u01a1ng 9\u201d.<\/p>\n

      HI+HI \u2192 H2 +I2<\/p>\n

      Th\u1ee9 hai, n\u0103ng l\u01b0\u1ee3ng ho\u1ea1t h\u00f3a l\u00e0 g\u00ec? \u0110\u1ec3 HI v\u00e0 HI ph\u1ea3n \u1ee9ng v\u00e0 chuy\u1ec3n th\u00e0nh H2 v\u00e0 I2, c\u1ea7n m\u1ed9t n\u0103ng l\u01b0\u1ee3ng nh\u1ea5t \u0111\u1ecbnh (H\u00ecnh 3.13<\/em>). S\u1ef1 thay \u0111\u1ed5i kh\u00f4ng di\u1ec5n ra tr\u1eeb khi n\u0103ng l\u01b0\u1ee3ng n\u00e0y b\u1ecb v\u01b0\u1ee3t qua. N\u00f3i c\u00e1ch kh\u00e1c, n\u0103ng l\u01b0\u1ee3ng ho\u1ea1t h\u00f3a l\u00e0 c\u1ea7n thi\u1ebft \u0111\u1ec3 thay \u0111\u1ed5i ch\u1ea5t ph\u1ea3n \u1ee9ng th\u00e0nh s\u1ea3n ph\u1ea9m. Ng\u01b0\u1ee3c l\u1ea1i, n\u1ebfu kh\u00f4ng v\u01b0\u1ee3t qu\u00e1 n\u0103ng l\u01b0\u1ee3ng ho\u1ea1t h\u00f3a, c\u00e1c ch\u1ea5t ph\u1ea3n \u1ee9ng kh\u00f4ng c\u00f3 kh\u1ea3 n\u0103ng t\u1ea1o ra s\u1ea3n ph\u1ea9m. N\u00f3i c\u00e1ch kh\u00e1c, c\u00f3 m\u1ed9t ng\u01b0\u1ee1ng. V\u00ed d\u1ee5, s\u1ef1 tho\u00e1i h\u00f3a m\u00f4 x\u1ea3y ra \u1edf 57\u00b0C trong h\u01a1n 10 s (H\u00ecnh 3.12<\/em>). Nh\u00ecn v\u00e0o 45 v\u00e0 55\u00b0C \u1edf 10 gi\u00e2y, 55\u00b0C cao h\u01a1n 45\u00b0C, nh\u01b0ng n\u00f3 ch\u01b0a v\u01b0\u1ee3t qu\u00e1 ng\u01b0\u1ee1ng 57\u00b0C, v\u00ec v\u1eady kh\u00f4ng c\u00f3 s\u1ef1 thay \u0111\u1ed5i \u1edf c\u1ea3 45 v\u00e0 55\u00b0C. N\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c coi l\u00e0 m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng t\u1ea5t c\u1ea3 ho\u1eb7c kh\u00f4ng, nh\u01b0ng hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y x\u1ea3y ra do s\u1ef1 tho\u00e1i h\u00f3a m\u00f4 ti\u1ebfn tri\u1ec3n nhanh ch\u00f3ng khi ng\u01b0\u1ee1ng b\u1ecb v\u01b0\u1ee3t qua do t\u00ednh ch\u1ea5t h\u00e0m m\u0169 c\u1ee7a n\u00f3 [1].<\/p>\n

      \"Bi\u1ec3u
      Bi\u1ec3u \u0111\u1ed3 th\u1ebf n\u0103ng \u0111\u1ec3 ph\u00e2n h\u1ee7y HI<\/figcaption><\/figure>\n

      H\u00ecnh 3.13 <\/strong>Bi\u1ec3u \u0111\u1ed3 th\u1ebf n\u0103ng \u0111\u1ec3 ph\u00e2n h\u1ee7y HI<\/p>\n

      M\u1ed9t v\u00ed d\u1ee5 c\u1ee5 th\u1ec3 l\u00e0, trong qu\u00e1 tr\u00ecnh tr\u1ebb h\u00f3a kh\u00f4ng x\u00e2m l\u1ea5n, b\u1eafn 100 tia m\u1ed7i tu\u1ea7n v\u1edbi k\u1ef9 thu\u1eadt genesis s\u1ebd kh\u00f4ng hi\u1ec7u qu\u1ea3 v\u00ec th\u1eddi gian quy tr\u00ecnh qu\u00e1 ng\u1eafn v\u00e0 n\u00f3 kh\u00f4ng v\u01b0\u1ee3t qu\u00e1 ng\u01b0\u1ee1ng. Thay v\u00e0o \u0111\u00f3, 10.000 tia trong m\u1ed9t l\u1ea7n \u0111i\u1ec1u tr\u1ecb s\u1ebd c\u00f3 hi\u1ec7u qu\u1ea3 v\u00ec n\u00f3 v\u01b0\u1ee3t qu\u00e1 ng\u01b0\u1ee1ng.<\/p>\n

      T\u1ea7n s\u1ed1<\/h2>\n

      M\u00f4 h\u00ecnh quang nhi\u1ec7t h\u1ecdc<\/h3>\n

      C\u00e1c m\u00f4 h\u00ecnh quang nhi\u1ec7t h\u1ecdc \u0111\u00e3 \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh c\u00e1c th\u00f4ng s\u1ed1 laser th\u00edch h\u1ee3p [31]. M\u00f4 h\u00ecnh quang nhi\u1ec7t h\u1ecdc \u0111\u01b0\u1ee3c chia th\u00e0nh ba giai \u0111o\u1ea1n theo th\u1ee9 t\u1ef1 c\u1ee7a c\u00e1c ph\u1ea3n \u1ee9ng m\u00f4 do laser g\u00e2y ra. \u0110\u1ea7u ti\u00ean l\u00e0 giai \u0111o\u1ea1n quang h\u1ecdc, n\u01a1i c\u00e1c photon \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5 b\u1edfi m\u00f4 \u0111\u00edch. \u0110\u1ec3 tia laser \u0111\u01b0\u1ee3c m\u00f4 \u0111\u00edch h\u1ea5p th\u1ee5 c\u00f3 ch\u1ecdn l\u1ecdc, c\u1ea7n ch\u1ecdn b\u01b0\u1edbc s\u00f3ng c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 trong m\u00f4 \u0111\u00edch cao h\u01a1n so v\u1edbi m\u00f4 xung quanh. Nh\u01b0 v\u1eady, giai \u0111o\u1ea1n quang h\u1ecdc l\u00e0 giai \u0111o\u1ea1n ch\u1ecdn b\u01b0\u1edbc s\u00f3ng. B\u00ean c\u1ea1nh \u0111\u00f3, v\u00ec OPD \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh theo b\u01b0\u1edbc s\u00f3ng, \u0111\u1ed9 s\u00e2u c\u1ee7a m\u00f4 \u0111\u00edch c\u0169ng c\u1ea7n \u0111\u01b0\u1ee3c xem x\u00e9t \u1edf giai \u0111o\u1ea1n n\u00e0y.<\/p>\n

      Th\u1ee9 hai l\u00e0 giai \u0111o\u1ea1n nhi\u1ec7t n\u01a1i c\u00e1c photon chuy\u1ec3n th\u00e0nh nhi\u1ec7t. \u0110\u1ec3 gi\u1ea3m thi\u1ec3u thi\u1ec7t h\u1ea1i cho m\u00f4 xung quanh, giai \u0111o\u1ea1n nhi\u1ec7t c\u1ea7n \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh theo l\u00fd thuy\u1ebft v\u1ec1 quang nhi\u1ec7t ch\u1ecdn l\u1ecdc \u0111\u1ec3 m\u00f4 \u0111\u00edch kh\u00f4ng truy\u1ec1n nhi\u1ec7t sang m\u00f4 xung quanh. Nh\u01b0 v\u1eady, giai \u0111o\u1ea1n nhi\u1ec7t l\u00e0 giai \u0111o\u1ea1n l\u1ef1a ch\u1ecdn \u0111\u1ed9 d\u00e0i xung.<\/p>\n

      Th\u1ee9 ba l\u00e0 qu\u00e1 tr\u00ecnh bi\u1ebfn t\u00ednh m\u00f4. Khi nhi\u1ec7t \u0111\u01b0\u1ee3c t\u00e1c \u0111\u1ed9ng v\u00e0o m\u00f4 \u0111\u00edch, c\u00e1c \u0111\u1eb7c t\u00ednh quang h\u1ecdc c\u1ee7a m\u00f4 s\u1ebd thay \u0111\u1ed5i. V\u00ed d\u1ee5, sau khi chi\u1ebfu x\u1ea1 IPL tr\u00ean c\u00e1c \u0111\u1ed1m n\u00e2u, s\u1ef1 chuy\u1ec3n s\u1eadm m\u00e0u s\u1ebd \u0111\u01b0\u1ee3c ki\u1ec3m tra \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh xem m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u00f3 ph\u00f9 h\u1ee3p hay kh\u00f4ng (\u0111i\u1ec3m k\u1ebft th\u00fac l\u00e2m s\u00e0ng). Giai \u0111o\u1ea1n n\u00e0y t\u01b0\u01a1ng \u1ee9ng v\u1edbi qu\u00e1 tr\u00ecnh bi\u1ebfn t\u00ednh m\u00f4. Do \u0111\u00f3, th\u1ee9 t\u1ef1 l\u1ef1a ch\u1ecdn c\u00e1c th\u00f4ng s\u1ed1 laser nh\u01b0 sau. \u0110\u1ea7u ti\u00ean, ch\u1ecdn b\u01b0\u1edbc s\u00f3ng. Ti\u1ebfp theo, x\u00e1c \u0111\u1ecbnh \u0111\u1ed9 d\u00e0i xung. Cu\u1ed1i c\u00f9ng, quan s\u00e1t ph\u1ea3n \u1ee9ng c\u1ee7a m\u00f4 \u0111\u1ec3 ki\u1ec3m so\u00e1t m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng.<\/p>\n

      B\u01b0\u1edbc s\u00f3ng \u2192 \u0111\u1ed9 d\u00e0i xung\u00a0 \u2192 k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m \u2192 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng.<\/p>\n

      T\u00f4i ngh\u0129 r\u1eb1ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m n\u00ean \u0111\u01b0\u1ee3c th\u00eam v\u00e0o c\u00e1c th\u1ee9 t\u1ef1 ch\u1ecdn ba th\u00f4ng s\u1ed1 laser n\u00e0y. K\u00edch th\u01b0\u1edbc \u0111i\u1ec3m ph\u1ea3i \u0111\u01b0\u1ee3c th\u00eam v\u00e0o tr\u01b0\u1edbc m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng. Khi th\u1ef1c hi\u1ec7n \u0111i\u1ec1u tr\u1ecb b\u1eb1ng laser, vi\u1ec7c x\u00e1c \u0111\u1ecbnh k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m l\u00e0 \u0111i\u1ec1u c\u1ea7n thi\u1ebft, \u0111\u1eb7c bi\u1ec7t l\u00e0 khi \u0111i\u1ec1u tr\u1ecb l\u1edbp b\u00ec, v\u00ec m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng thay \u0111\u1ed5i theo k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m (hi\u1ec7u \u1ee9ng k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m). Do \u0111\u00f3, c\u00e1c th\u00f4ng s\u1ed1 laser c\u1ea7n \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh theo th\u1ee9 t\u1ef1 b\u01b0\u1edbc s\u00f3ng, \u0111\u1ed9 d\u00e0i xung, k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m v\u00e0 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng.<\/p>\n

      Qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4<\/h3>\n

      Ch\u00fang ta h\u00e3y xem x\u00e9t k\u1ef9 h\u01a1n qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4. Qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4 x\u1ea3y ra sau v\u00e0i ch\u1ee5c \u0111\u1ebfn h\u00e0ng tr\u0103m mili gi\u00e2y sau khi chi\u1ebfu tia laser. Trong qu\u00e1 tr\u00ecnh bi\u1ebfn t\u00ednh m\u00f4, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 c\u1ee7a h\u1ea7u h\u1ebft c\u00e1c m\u00f4 \u0111\u01b0\u1ee3c t\u0103ng l\u00ean t\u1eeb ba \u0111\u1ebfn b\u1ed1n l\u1ea7n. V\u00ed d\u1ee5, sau khi chi\u1ebfu x\u1ea1 IPL tr\u00ean \u0111\u1ed1m n\u00e2u, \u0111\u1ed1m n\u00e2u chuy\u1ec3n sang m\u00e0u \u0111en, c\u00f3 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 cao h\u01a1n \u0111\u1ed1m n\u00e2u ban \u0111\u1ea7u. Ngo\u00e0i ra, \u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u b\u1eb1ng laser Nd: YAG xung d\u00e0i d\u1eabn \u0111\u1ebfn h\u00ecnh th\u00e0nh c\u1ee5c m\u00e1u \u0111\u00f4ng trong m\u00e1u \u0111\u1ecf. \u0110i\u1ec1u n\u00e0y c\u0169ng tr\u00f4ng s\u1eadm m\u00e0u h\u01a1n v\u00e0 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 \u0111\u01b0\u1ee3c t\u0103ng l\u00ean.<\/p>\n

      Sau qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 c\u1ee7a m\u00f4 \u0111\u00edch \u0111\u01b0\u1ee3c t\u0103ng l\u00ean, \u0111\u1ed3ng th\u1eddi t\u0103ng t\u1ef7 l\u1ec7 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 c\u1ee7a m\u00f4 \u0111\u00edch v\u1edbi m\u00f4 xung quanh. Do \u0111\u00f3, m\u00f4 \u0111\u00edch c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111i\u1ec1u tr\u1ecb m\u1ed9t c\u00e1ch ch\u1ecdn l\u1ecdc h\u01a1n. V\u00ed d\u1ee5, m\u1ed9t tia laser k\u1ebft h\u1ee3p, chi\u1ebfu tia PDL 595 nm tr\u01b0\u1edbc, ti\u1ebfp theo l\u00e0 laser Nd: YAG 1064 nm, s\u1eed d\u1ee5ng nguy\u00ean t\u1eafc c\u1ee7a qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4 [16]. Ngo\u00e0i ra, c\u00f3 th\u1ec3 chi\u1ebfu tia laser l\u1eb7p l\u1ea1i ngay sau tia ban \u0111\u1ea7u (ph\u01b0\u01a1ng ph\u00e1p ch\u1ed3ng xung, l\u1eb7p l\u1ea1i).<\/p>\n

      Chu\u1ed7i xung<\/h3>\n

      Ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c chia th\u00e0nh hai: chu\u1ed7i xung \u0111\u1ed3ng nh\u1ea5t v\u00e0 chu\u1ed7i xung kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t [31]. Chu\u1ed7i xung \u0111\u1ed3ng nh\u1ea5t l\u00e0 m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p chi\u1ebfu x\u1ea1 xung v\u1edbi c\u00f9ng \u0111\u1ed9 d\u00e0i xung v\u00e0 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng gi\u1ed1ng nhau trong c\u00f9ng m\u1ed9t kho\u1ea3ng th\u1eddi gian. V\u1edbi ph\u01b0\u01a1ng ph\u00e1p n\u00e0y, nhi\u1ec7t \u0111\u1ed9 t\u0103ng d\u1ea7n khi chi\u1ebfu x\u1ea1 xung l\u1eb7p l\u1ea1i (H\u00ecnh 3.14<\/em>). Trong chu\u1ed7i xung kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t, xung \u0111\u1ea7u ti\u00ean l\u00e0 m\u1ea1nh v\u00e0 xung ti\u1ebfp theo l\u00e0 y\u1ebfu \u0111\u1ec3 duy tr\u00ec nhi\u1ec7t \u0111\u1ed9 kh\u00f4ng \u0111\u1ed5i trong t\u1ed5ng \u0111\u1ed9 d\u00e0i xung (H\u00ecnh 3.15<\/em>). Chu\u1ed7i xung kh\u00f4ng \u0111\u1ed3ng nh\u1ea5t l\u00e0 l\u00fd t\u01b0\u1edfng, nh\u01b0ng ch\u00fang \u0111\u00f2i h\u1ecfi t\u00ednh to\u00e1n ch\u00ednh x\u00e1c do \u0111\u00f3 m\u00e1y laser ph\u1ea3i \u0111\u01b0\u1ee3c c\u00e0i \u0111\u1eb7t tr\u01b0\u1edbc, kh\u00f4ng ph\u1ea3i do ng\u01b0\u1eddi v\u1eadn h\u00e0nh \u0111i\u1ec1u ch\u1ec9nh. Ch\u00fang t\u00f4i s\u1ebd t\u1eadp trung v\u00e0o chu\u1ed7i xung \u0111\u1ed3ng nh\u1ea5t m\u00e0 ng\u01b0\u1eddi v\u1eadn h\u00e0nh c\u00f3 th\u1ec3 ki\u1ec3m so\u00e1t.<\/p>\n

      Jia et al. \u00e1p d\u1ee5ng chu\u1ed7i xung \u0111\u1ed3ng nh\u1ea5t v\u00e0 chi\u1ebfu x\u1ea1 l\u1eb7p l\u1ea1i laser Q-switched Nd: YAG 1064-nm tr\u00ean \u1ed1ng th\u1ee7y tinh mao d\u1eabn c\u00f3 \u0111\u01b0\u1eddng k\u00ednh trong 1 mm v\u00e0 d\u00e0y 0,1 mm \u0111\u1ec3 \u0111o s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 [32]. C\u00e1c th\u00f4ng s\u1ed1 l\u00e0 k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 2 mm v\u00e0 \u0111\u1ed9 d\u00e0i xung 0,3 ms (genesis mode). K\u1ebft qu\u1ea3 nh\u01b0 sau. Khi nhi\u1ec7t \u0111\u1ed9 \u0111\u00f4ng m\u00e1u kho\u1ea3ng 73\u00b0C, nhi\u1ec7t \u0111\u1ed9 da v\u01b0\u1ee3t qu\u00e1 nhi\u1ec7t \u0111\u1ed9 \u0111\u00f4ng m\u00e1u khi chi\u1ebfu tia b\u1ed1n l\u1ea7n \u1edf 30 J\/cm2<\/sup>, 4 Hz, v\u00e0 nhi\u1ec7t \u0111\u1ed9 da v\u01b0\u1ee3t qu\u00e1 nhi\u1ec7t \u0111\u1ed9 \u0111\u00f4ng m\u00e1u khi chi\u1ebfu tia hai l\u1ea7n \u1edf 40 J\/cm2<\/sup>, 2 Hz (H\u00ecnh 3.16<\/em>).<\/p>\n

      \"S\u1ef1
      S\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 \u0111\u00edch v\u00e0 bi\u1ec3u b\u00ec theo chu\u1ed7i xung \u0111\u1ed3ng nh\u1ea5t.<\/figcaption><\/figure>\n

      H\u00ecnh 3.14 <\/strong>S\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 \u0111\u00edch v\u00e0 bi\u1ec3u b\u00ec theo chu\u1ed7i xung \u0111\u1ed3ng nh\u1ea5t.<\/p>\n

      \"Thay
      Thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 \u1edf c\u00e1c m\u00f4 \u0111\u00edch v\u00e0 xung quanh theo chu\u1ed7i xung kh\u00f4ng \u0111\u1ed3ng \u0111\u1ec1u<\/figcaption><\/figure>\n

      H\u00ecnh 3.15 <\/strong>Thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 \u1edf c\u00e1c m\u00f4 \u0111\u00edch v\u00e0 xung quanh theo chu\u1ed7i xung kh\u00f4ng \u0111\u1ed3ng \u0111\u1ec1u.<\/p>\n

      T\u1eeb k\u1ebft qu\u1ea3 c\u1ee7a b\u00e0i b\u00e1o n\u00e0y, c\u00f3 th\u1ec3 th\u1ea5y r\u1eb1ng khi \u0111\u01b0\u1ee3c chi\u1ebfu tia nhi\u1ec1u l\u1ea7n v\u1edbi m\u1ed9t chu\u1ed7i xung \u0111\u1ed3ng nh\u1ea5t, s\u1ef1 t\u0103ng nhi\u1ec7t \u0111\u1ed9 thay \u0111\u1ed5i ph\u1ee5 thu\u1ed9c v\u00e0o ba th\u00f4ng s\u1ed1: m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng, t\u1ea7n s\u1ed1 v\u00e0 s\u1ed1 l\u01b0\u1ee3ng xung.<\/p>\n

      V\u1eady l\u00e0m th\u1ebf n\u00e0o ch\u00fang ta c\u00f3 th\u1ec3 th\u1ef1c s\u1ef1 \u0111i\u1ec1u ch\u1ec9nh ba th\u00f4ng s\u1ed1 n\u00e0y? Ti\u1ebfp theo, h\u00e3y xem c\u00e1ch s\u1eed d\u1ee5ng qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4 trong \u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u v\u00e0 c\u00e1ch \u0111i\u1ec1u ch\u1ec9nh ba th\u00f4ng s\u1ed1.<\/p>\n

      Qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4 trong \u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u<\/h3>\n

      Qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong \u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u kh\u00f4ng? \u0110\u1ea7u ti\u00ean, h\u00e3y xem x\u00e9t c\u00e1c hi\u1ec7n t\u01b0\u1ee3ng trong m\u1ea1ch m\u00e1u trong qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4. Vi\u1ec7c chi\u1ebfu tia laser v\u00e0o m\u00e1u t\u1ea1o ra MetHb v\u00e0 c\u1ee5c m\u00e1u \u0111\u00f4ng trong qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4. \u0110\u1eb7c bi\u1ec7t, \u0111\u01b0\u1eddng cong h\u1ea5p th\u1ee5 c\u1ee7a c\u1ee5c m\u00e1u \u0111\u00f4ng t\u0103ng l\u00ean tr\u00ean \u0111\u01b0\u1eddng cong h\u1ea5p th\u1ee5 c\u1ee7a m\u00e1u ban \u0111\u1ea7u. C\u00f3 th\u1ec3 chi\u1ebfu tia nhi\u1ec1u l\u1ea7n l\u00ean c\u1ee5c \u0111\u00f4ng v\u00ec \u0111\u01b0\u1eddng cong h\u1ea5p th\u1ee5 kh\u00f4ng d\u1ecbch chuy\u1ec3n sang b\u00ean ph\u1ea3i nh\u01b0 metHb (d\u1ecbch chuy\u1ec3n m\u00e0u s\u1eafc ho\u1eb7c d\u1ecbch chuy\u1ec3n \u0111\u1ecf [14], xem \u201cCh\u01b0\u01a1ng 6\u201d) m\u00e0 t\u0103ng l\u00ean tr\u00ean. C\u00e1c ph\u01b0\u01a1ng ph\u00e1p \u0111i\u1ec3n h\u00ecnh l\u00e0 ph\u01b0\u01a1ng ph\u00e1p ch\u1ed3ng xung nhi\u1ec1u l\u1ea7n PDL 585-nm t\u1ea1i c\u00f9ng m\u1ed9t \u0111i\u1ec3m v\u00e0 ph\u01b0\u01a1ng ph\u00e1p \u0111a xung c\u1ee7a IPL.<\/p>\n

      \"\u0110\u00e1p
      \u0110\u00e1p \u1ee9ng nhi\u1ec7t c\u1ee7a m\u1eabu m\u00e1u trong 1 gi\u00e2y \u1edf (a) 30 v\u00e0 (b) 40 J\/cm2.\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0<\/span><\/figcaption><\/figure>\n

      H\u00ecnh 3.16 <\/strong>\u0110\u00e1p \u1ee9ng nhi\u1ec7t c\u1ee7a m\u1eabu m\u00e1u trong 1 gi\u00e2y \u1edf (a) 30 v\u00e0 (b) 40 J\/cm2<\/sup>.<\/p>\n

      Tuy nhi\u00ean, c\u1ea7n th\u1eadn tr\u1ecdng khi s\u1eed d\u1ee5ng laser Nd: YAG xung d\u00e0i 1064 v\u00ec vi\u1ec7c s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p ch\u1ed3ng xung c\u00f3 th\u1ec3 g\u00e2y b\u1ecfng do h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 t\u0103ng nhanh do s\u1ef1 xu\u1ea5t hi\u1ec7n c\u1ee7a metHb.<\/p>\n

      Myhill et al. chi\u1ebfu tia IPL nhi\u1ec1u l\u1ea7n tr\u00ean da l\u1ee3n s\u1ed1ng v\u00e0 quan s\u00e1t th\u1ea5y s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 da [33]. M\u1ed9t nh\u00f3m \u0111\u01b0\u1ee3c chi\u1ebfu l\u1eb7p l\u1ea1i b\u1ee9c x\u1ea1 16 J\/cm2<\/sup> v\u1edbi kho\u1ea3ng ngh\u1ec9 8 s v\u00e0 nh\u00f3m c\u00f2n l\u1ea1i v\u1edbi c\u00f4ng su\u1ea5t 18 J\/cm2<\/sup> kho\u1ea3ng ngh\u1ec9 9 s. L\u00fd do cho kho\u1ea3ng th\u1eddi gian ngh\u1ec9 8 v\u00e0 9 s n\u00e0y l\u00e0 \u0111\u1ec3 l\u00e0m m\u00e1t da ho\u00e0n to\u00e0n sau khi chi\u1ebfu IPL v\u00e0 lo\u1ea1i tr\u1eeb t\u00edch t\u1ee5 nhi\u1ec7t do chi\u1ebfu tia nhi\u1ec1u l\u1ea7n. K\u1ebft qu\u1ea3 \u0111o nhi\u1ec7t \u0111\u1ed9 cho th\u1ea5y ngay c\u1ea3 sau khi chi\u1ebfu tia nhi\u1ec1u l\u1ea7n, nhi\u1ec7t \u0111\u1ed9 ngay tr\u01b0\u1edbc khi chi\u1ebfu tia laser tr\u1edf l\u1ea1i nhi\u1ec7t \u0111\u1ed9 ban \u0111\u1ea7u t\u01b0\u01a1ng \u0111\u1ed1i \u1ed5n \u0111\u1ecbnh, nh\u01b0ng nhi\u1ec7t \u0111\u1ed9 t\u1ed1i \u0111a t\u0103ng d\u1ea7n khi chi\u1ebfu tia nhi\u1ec1u l\u1ea7n. L\u00fd do t\u1ea1i sao nhi\u1ec7t \u0111\u1ed9 t\u0103ng d\u1ea7n ngay c\u1ea3 khi IPL \u0111\u01b0\u1ee3c chi\u1ebfu x\u1ea1 l\u1eb7p l\u1ea1i v\u1edbi kho\u1ea3ng ngh\u1ec9 8-9 s, m\u1ed9t kho\u1ea3ng th\u1eddi gian t\u01b0\u01a1ng \u0111\u1ed1i d\u00e0i, cho th\u1ea5y r\u1eb1ng c\u00e1c y\u1ebfu t\u1ed1 kh\u00e1c t\u1ed3n t\u1ea1i ngo\u00e0i MetHb v\u00e0 c\u1ee5c m\u00e1u \u0111\u00f4ng. Myhill et al. \u01b0\u1edbc t\u00ednh r\u1eb1ng h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 t\u0103ng l\u00ean khi m\u1ea1ch m\u00e1u gi\u00e3n n\u1edf, l\u01b0\u1ee3ng m\u00e1u t\u0103ng v\u00e0 n\u1ed3ng \u0111\u1ed9 hemoglobin t\u0103ng do t\u1ed5n th\u01b0\u01a1ng m\u1ea1ch m\u00e1u d\u01b0\u1edbi \u0111\u00f4ng m\u00e1u \u1edf nhi\u1ec7t \u0111\u1ed9 th\u1ea5p m\u00e0 qu\u00e1 tr\u00ecnh \u0111\u00f4ng m\u00e1u kh\u00f4ng th\u1ec3 x\u1ea3y ra.<\/p>\n

      T\u00f3m l\u1ea1i, c\u00f3 th\u1ec3 th\u1ea5y r\u1eb1ng h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 b\u1ecb thay \u0111\u1ed5i do (1) MetHb, (2) c\u1ee5c m\u00e1u \u0111\u00f4ng, v\u00e0<\/p>\n

      (3) l\u01b0u l\u01b0\u1ee3ng m\u00e1u t\u0103ng l\u00ean trong qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4. V\u1eady nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 thay \u0111\u1ed5i nh\u01b0 th\u1ebf n\u00e0o khi h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 thay \u0111\u1ed5i?<\/p>\n

      MetHb v\u00e0 c\u1ee5c m\u00e1u \u0111\u00f4ng \u0111\u01b0\u1ee3c h\u00ecnh th\u00e0nh trong ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i ho\u1eb7c h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 t\u0103ng khi l\u01b0u l\u01b0\u1ee3ng m\u00e1u t\u0103ng. Trong c\u00f9ng m\u1ed9t m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng, nhi\u1ec7t \u0111\u1ed9 t\u0103ngkhi h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 t\u0103ng. Li et al. \u0111o s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 b\u1eb1ng c\u00e1ch chi\u1ebfu x\u1ea1 l\u1eb7p l\u1ea1i tia laser Q-switch Nd: YAG 1064 nm v\u1edbi \u0111\u1ed9 d\u00e0i xung 0,3 ms tr\u00ean \u1ed1ng mao d\u1eabn ch\u1ee9a m\u00e1u (H\u00ecnh 3.17<\/em>) [34]. K\u1ebft qu\u1ea3 cho th\u1ea5y trong qu\u00e1 tr\u00ecnh chi\u1ebfu tia l\u1eb7p l\u1ea1i, nhi\u1ec7t \u0111\u1ed9 t\u0103ng li\u00ean t\u1ee5c nh\u01b0ng nhi\u1ec7t \u0111\u1ed9 t\u0103ng nhanh h\u01a1n do qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4 sau khi h\u00ecnh th\u00e0nh c\u1ee5c m\u00e1u \u0111\u00f4ng.<\/p>\n

      \"S\u1ef1
      S\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 trung b\u00ecnh c\u1ee7a t\u00e0u m\u1ee5c ti\u00eau v\u1edbi m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng l\u00e0 53 J _ cm2 v\u00e0 t\u1ea7n s\u1ed1 xung l\u00e0 8 Hz.<\/figcaption><\/figure>\n

      H\u00ecnh 3.17 <\/strong>S\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 trung b\u00ecnh c\u1ee7a t\u00e0u m\u1ee5c ti\u00eau v\u1edbi m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng l\u00e0 53 J \/ cm2 v\u00e0 t\u1ea7n s\u1ed1 xung l\u00e0 8 Hz.<\/p>\n

      Vi\u1ec7c chi\u1ebfu tia l\u1eb7p l\u1ea1i l\u00ean m\u1ea1ch m\u00e1u ban \u0111\u1ea7u d\u1eabn \u0111\u1ebfn nhi\u1ec7t \u0111\u1ed9 t\u0103ng l\u00ean \u1ed5n \u0111\u1ecbnh nh\u01b0ng sau qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4, nhi\u1ec7t \u0111\u1ed9 t\u0103ng l\u00ean nhanh ch\u00f3ng. \u0110\u1eb7c bi\u1ec7t, v\u00ec MetHb l\u00e0m t\u0103ng h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 c\u1ee7a n\u00f3 l\u00ean ba l\u1ea7n, m\u1ed9t laser h\u1ed3ng ngo\u1ea1i g\u1ea7n nh\u01b0 laser Q-switched Nd: YAG 1064 nm ch\u1ecbu s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 nhanh ch\u00f3ng trong qu\u00e1 tr\u00ecnh tho\u00e1i h\u00f3a m\u00f4 so v\u1edbi laser m\u1ea1ch m\u00e1u c\u00f3 b\u01b0\u1edbc s\u00f3ng 500-600 nm. Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i, nh\u01b0ng ph\u1ea3i c\u1ea9n th\u1eadn v\u00ec s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 \u0111\u1ed9t ng\u1ed9t c\u00f3 th\u1ec3 g\u00e2y ra t\u00e1c d\u1ee5ng ph\u1ee5 n\u1ebfu nhi\u1ec7t \u0111\u1ed9 v\u01b0\u1ee3t qua ng\u01b0\u1ee1ng g\u00e2y t\u1ed5n th\u01b0\u01a1ng v\u00e0 t\u0103ng qu\u00e1 ng\u01b0\u1ee1ng s\u1ed1ng s\u00f3t (xem trong \u201cCh\u01b0\u01a1ng 9\u201d).<\/p>\n

      Ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i<\/h3>\n

      Ti\u1ebfp theo, ch\u00fang ta s\u1ebd xem x\u00e9t c\u1ee5 th\u1ec3 ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i s\u1eed d\u1ee5ng c\u1ee5c m\u00e1u \u0111\u00f4ng v\u00e0 t\u0103ng l\u01b0u l\u01b0\u1ee3ng m\u00e1u.<\/p>\n

      Theo c\u00e1c b\u00e0i b\u00e1o c\u1ee7a Jia et al. v\u00e0 Li et al., b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng b\u01b0\u1edbc s\u00f3ng 1064 nm v\u00e0 chi\u1ebfu x\u1ea1 l\u1eb7p l\u1ea1i v\u1edbi \u0111\u1ed9 d\u00e0i xung 0,3 ms, nhi\u1ec7t \u0111\u1ed9 m\u00e1u c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u0103ng d\u1ea7n. Thi\u1ebft b\u1ecb laser Q-Switch Nd:YAG 1064-nm c\u1ee7a t\u00f4i kh\u00f4ng th\u1ec3 t\u0103ng n\u0103ng l\u01b0\u1ee3ng tr\u00ean 100 J\/cm2<\/sup> v\u1edbi \u0111\u1ed9 d\u00e0i xung 0,3 ms, k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 2 mm. T\u00f4i tin r\u1eb1ng c\u1ea7n c\u00f3 m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng \u00edt nh\u1ea5t 150 J\/cm2<\/sup>, v\u00ec v\u1eady t\u00f4i \u0111\u00e3 th\u1eed ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng laser Nd: YAG xung d\u00e0i thay v\u00ec laser Q-switch Nd: YAG. Hi\u1ec7n t\u1ea1i, c\u00e1c th\u00f4ng s\u1ed1 t\u00f4i s\u1eed d\u1ee5ng l\u00e0 k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 2 mm, 0,3 ms, 150 J\/cm2, 3 Hz v\u00e0 3\u20134 l\u1ea7n chi\u1ebfu. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111i\u1ec1u tr\u1ecb c\u00e1c m\u1ea1ch m\u00e1u nh\u1ecf c\u00f3 TRT d\u01b0\u1edbi 5 ms, kh\u00f4ng hi\u1ec7u qu\u1ea3 b\u1eb1ng laser Nd:YAG xung d\u00e0i th\u00f4ng th\u01b0\u1eddng. V\u00ec c\u00e1c m\u1ea1ch m\u00e1u c\u00f3 TRT t\u1eeb 5 ms tr\u1edf l\u00ean \u0111\u00e3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111i\u1ec1u tr\u1ecb b\u1eb1ng laser Nd: YAG xung d\u00e0i n\u00ean ch\u00fang kh\u00f4ng \u0111\u01b0\u1ee3c \u0111\u01b0a v\u00e0o nh\u00f3m \u0111i\u1ec1u tr\u1ecb.<\/p>\n

      T\u00f4i \u0111\u1eb7t t\u00ean cho ph\u01b0\u01a1ng ph\u00e1p t\u0103ng d\u1ea7n nhi\u1ec7t \u0111\u1ed9 b\u1eb1ng c\u00e1ch chi\u1ebfu tia l\u1eb7p l\u1ea1i v\u1edbi chu\u1ed7i xung \u0111\u1ed3ng nh\u1ea5t l\u00e0 \u201cph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i\u201d \u0111\u1ec3 d\u1ec5 hi\u1ec3u h\u01a1n. M\u1eb7c d\u00f9 t\u00f4i ch\u01b0a c\u00f3 \u0111\u1ee7 tr\u00ecnh \u0111\u1ed9 v\u1ec1 k\u1ef9 thu\u1eadt n\u00e0y, t\u00f4i c\u00f3 th\u1ec3 \u0111i\u1ec1u tr\u1ecb kh\u00f4ng ch\u1ec9 c\u00e1c m\u1ea1ch m\u00e1u t\u01b0\u01a1ng \u1ee9ng v\u1edbi TRT t\u1eeb 5 ms tr\u1edf l\u00ean m\u00e0 c\u00f2n m\u1ed9t s\u1ed1 m\u1ea1ch m\u00e1u c\u00f3 TRT t\u1eeb 5 ms tr\u1edf xu\u1ed1ng b\u1eb1ng ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i v\u1edbi laser Nd: YAG xung d\u00e0i. M\u1ed9t \u01b0u \u0111i\u1ec3m kh\u00e1c l\u00e0 ban xu\u1ea5t huy\u1ebft x\u1ea3y ra \u1edf PDL 585 nm kh\u00f4ng x\u1ea3y ra trong ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i b\u1eb1ng laser Nd: YAG xung d\u00e0i.<\/p>\n

      Nh\u01b0\u1ee3c \u0111i\u1ec3m c\u1ee7a ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i s\u1eed d\u1ee5ng laser Nd: YAG xung d\u00e0i nh\u01b0 sau. Th\u1ee9 nh\u1ea5t, b\u1ec7nh nh\u00e2n kh\u00f3 ch\u1ecbu do \u0111au, v\u00e0 th\u1ee9 hai, \u0111i\u1ec3m k\u1ebft th\u00fac l\u00e2m s\u00e0ng kh\u00f3 th\u1ea5y do k\u00edch th\u01b0\u1edbc m\u1ea1ch m\u00e1u nh\u1ecf. Th\u1ee9 ba, ngay c\u1ea3 khi s\u1ed1 l\u01b0\u1ee3ng xung l\u00e0 b\u1ed1n ho\u1eb7c n\u0103m, ch\u1ec9 c\u1ea7n m\u1ed9t<\/p>\n

      xung n\u1eefa l\u00e0 c\u00f3 th\u1ec3 b\u1ecb b\u1ecfng. Th\u1ee9 t\u01b0, th\u1eddi gian th\u1ee7 thu\u1eadt l\u00e2u v\u00ec m\u1ea1ch m\u00e1u c\u1ea7n ph\u1ea3i chi\u1ebfu tia t\u1eebng c\u00e1i m\u1ed9t. Th\u1ee9 n\u0103m, m\u1eb7c d\u00f9 t\u00f4i ch\u01b0a th\u1eed, nh\u01b0ng \u0111\u1ecf b\u1eebng m\u1eb7t do c\u00e1c t\u0129nh m\u1ea1ch m\u00e1u nh\u1ecf kh\u00f4ng d\u1ec5 d\u00e0ng nh\u00ecn th\u1ea5y b\u1eb1ng k\u00ednh l\u00fap, c\u00f3 kh\u1ea3 n\u0103ng kh\u00f4ng hi\u1ec7u qu\u1ea3 ho\u1eb7c d\u1ec5 g\u00e2y t\u00e1c d\u1ee5ng ph\u1ee5.<\/p>\n

      V\u1eady ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i ch\u1ec9 \u00e1p d\u1ee5ng cho \u0111i\u1ec1u tr\u1ecb m\u1ea1ch m\u00e1u? Kh\u00f4ng th\u1ec3 \u00e1p d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p xung l\u1eb7p l\u1ea1i \u0111\u1ec3 \u0111i\u1ec1u tr\u1ecb s\u1eafc t\u1ed1? \u0110i\u1ec1u n\u00e0y s\u1ebd \u0111\u01b0\u1ee3c gi\u1ea3i th\u00edch chi ti\u1ebft trong \u201cCh\u01b0\u01a1ng 7\u201d<\/p>\n

      Chi\u1ebfn l\u01b0\u1ee3c<\/h2>\n

      C\u00f3 ba chi\u1ebfn l\u01b0\u1ee3c \u0111\u1ec3 t\u0103ng nhi\u1ec7t \u0111\u1ed9 m\u1ed9t c\u00e1ch ch\u1ecdn l\u1ecdc ch\u1ec9 trong m\u1ed9t khu v\u1ef1c v\u1ec1 m\u1eb7t kh\u00f4ng gian (B\u1ea3ng 3.5<\/em>) [14]. \u0110\u1ea7u ti\u00ean, quang nhi\u1ec7t c\u00f3 ch\u1ecdn l\u1ecdc, th\u1ee9 hai, l\u00e0m m\u00e1t bi\u1ec3u b\u00ec v\u00e0 th\u1ee9 ba, quang nhi\u1ec7t ph\u00e2n \u0111o\u1ea1n. Ch\u00fang ta h\u00e3y xem x\u00e9t l\u1ea7n l\u01b0\u1ee3t ba chi\u1ebfn l\u01b0\u1ee3c n\u00e0y.<\/p>\n

      Ph\u01b0\u01a1ng ph\u00e1p \u0111\u1ea7u ti\u00ean l\u00e0 l\u00fd thuy\u1ebft v\u1ec1 qu\u00e1 tr\u00ecnh quang nhi\u1ec7t ch\u1ecdn l\u1ecdc. S\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 t\u0103ng nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 \u0111\u00edch trong khi b\u1ea3o v\u1ec7 m\u00f4 xung quanh.<\/p>\n

      B\u1ea3ng 3.5 <\/strong>Chi\u1ebfn l\u01b0\u1ee3c \u0111i\u1ec1u tr\u1ecb b\u1eb1ng laser<\/p>\n\n\n\n\n\n\n
      T\u0103ng nhi\u1ec7t \u0111\u1ed9 ch\u1ecdn l\u1ecdc theo kh\u00f4ng gian<\/td>\n<\/tr>\n
      1<\/td>\nQuang nhi\u1ec7t ch\u1ecdn l\u1ecdc<\/p>\n

      A.H\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 (b\u01b0\u1edbc s\u00f3ng), m\u1eadt \u0111\u1ed9 th\u1ec3 nhi\u1ec5m s\u1eafc<\/p>\n

      B. \u0110\u1ed9 d\u00e0i xung (nhi\u1ec7t \u0111\u1ed9ng h\u1ecdc ch\u1ecdn l\u1ecdc)<\/td>\n<\/tr>\n

      2<\/td>\n\u00a0L\u00e0m m\u00e1t bi\u1ec3u b\u00ec<\/td>\n<\/tr>\n
      3<\/td>\nQuang nhi\u1ec7t ph\u00e2n \u0111o\u1ea1n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      \u0394T<\/em>: \u0111\u1ed9 t\u0103ng nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u1ee5c ti\u00eau<\/p>\n

      \u00b5<\/em>a<\/em>: h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5<\/p>\n

      F<\/em>z<\/em>: m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng c\u1ee5c b\u1ed9 d\u01b0\u1edbi b\u1ec1 m\u1eb7t<\/p>\n

      \u03c1<\/em>: m\u1eadt \u0111\u1ed9<\/p>\n

      c<\/em>: nhi\u1ec7t dung ri\u00eang<\/p>\n

      g<\/em>: h\u1ec7 s\u1ed1 h\u00ecnh h\u1ecdc (m\u1ed9t cho m\u1eb7t ph\u1eb3ng, hai cho h\u00ecnh tr\u1ee5 v\u00e0 ba cho h\u00ecnh c\u1ea7u)<\/p>\n

      \u03c4<\/em>p<\/em>: \u0111\u1ed9 d\u00e0i xung laser<\/p>\n

      \u03c4<\/em>r<\/em>: th\u1eddi gian gi\u00e3n nhi\u1ec7t c\u1ee7a m\u1ee5c ti\u00eau (TRT)<\/p>\n

      C\u00e1c bi\u1ebfn trong c\u00f4ng th\u1ee9c n\u00e0y bao g\u1ed3m m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng, h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5, TRT, \u0111\u1ed9 d\u00e0i xung, h\u1ec7 s\u1ed1 h\u00ecnh h\u1ecdc, m\u1eadt \u0111\u1ed9 v\u00e0 nhi\u1ec7t dung ri\u00eang. Tho\u1ea1t nh\u00ecn, b\u1ea1n c\u00f3 th\u1ec3 ngh\u0129 r\u1eb1ng vi\u1ec7c \u0111i\u1ec1u tr\u1ecb c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n b\u1eb1ng c\u00e1ch \u0111i\u1ec1u ch\u1ec9nh m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng ho\u1eb7c \u0111\u1ed9 d\u00e0i xung, nh\u01b0ng th\u1ef1c t\u1ebf kh\u00f4ng ph\u1ea3i v\u1eady. V\u00ed d\u1ee5, gi\u1ea3 s\u1eed c\u00f3 m\u1ed9t \u0111\u1ed1m n\u00e2u 5 mm v\u00e0 m\u00f4 b\u00ecnh th\u01b0\u1eddng bao quanh \u0111\u1ed1m n\u00e2u. N\u1ebfu tia laser \u0111\u01b0\u1ee3c chi\u1ebfu v\u1edbi k\u00edch th\u01b0\u1edbc \u0111i\u1ec3m 10 mm, t\u1ea1i \u0111i\u1ec3m chi\u1ebfu s\u1ebd c\u00f3 s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 c\u1ee7a \u0111\u1ed1m n\u00e2u (\u0394T \u1edf \u0111\u1ed1m n\u00e2u) v\u00e0 s\u1ef1 thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 c\u1ee7a m\u00f4 b\u00ecnh th\u01b0\u1eddng (\u0394T \u1edf m\u00f4 b\u00ecnh th\u01b0\u1eddng). Kh\u00f4ng c\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng v\u00e0 \u0111\u1ed9 d\u00e0i xung trong c\u00f9ng m\u1ed9t v\u1ecb tr\u00ed. S\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa hai m\u00f4 l\u00e0 g\u00ec? \u0110\u1ea7u ti\u00ean l\u00e0 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 v\u00e0 th\u1ee9 hai l\u00e0 TRT. N\u00f3i c\u00e1ch kh\u00e1c, ch\u1ec9 c\u00f3 \u0111\u1ed1m n\u00e2u m\u1edbi c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u0111i\u1ec1u tr\u1ecb ch\u1ecdn l\u1ecdc b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng ch\u00eanh l\u1ec7ch h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 melanin gi\u1eefa \u0111\u1ed1m n\u00e2u v\u00e0 m\u00f4 b\u00ecnh th\u01b0\u1eddng ho\u1eb7c ch\u00eanh l\u1ec7ch m\u1eadt \u0111\u1ed9 gi\u1eefa \u0111\u1ed1m n\u00e2u v\u00e0 m\u00f4 b\u00ecnh th\u01b0\u1eddng. Ngo\u00e0i ra, nhi\u1ec7t \u0111\u1ed9ng h\u1ecdc ch\u1ecdn l\u1ecdc c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111i\u1ec1u tr\u1ecb ch\u1ecdn l\u1ecdc t\u1eebng \u0111i\u1ec3m m\u1ed9t trong khi gi\u1ea3m tu\u1ea7n t\u1ef1 t\u1eeb \u0111\u1ed9 d\u00e0i xung d\u00e0i \u0111\u1ebfn \u0111\u1ed9 d\u00e0i xung ng\u1eafn.<\/p>\n

      Ph\u01b0\u01a1ng ph\u00e1p th\u1ee9 hai l\u00e0 l\u00e0m m\u00e1t bi\u1ec3u b\u00ec. V\u00ed d\u1ee5, trong tri\u1ec7t l\u00f4ng b\u1eb1ng laser, c\u1ea3 nhi\u1ec7t \u0111\u1ed9 c\u1ee7a melanin bi\u1ec3u b\u00ec v\u00e0 l\u00f4ng l\u1edbp b\u00ec \u0111\u1ec1u t\u0103ng l\u00ean. Khi l\u00e0m m\u00e1t bi\u1ec3u b\u00ec c\u01b0\u1ee1ng b\u1ee9c l\u00e0m gi\u1ea3m nhi\u1ec7t \u0111\u1ed9 bi\u1ec3u b\u00ec, nhi\u1ec7t \u0111\u1ed9 c\u1ee7a l\u00f4ng l\u1edbp b\u00ec s\u1ebd t\u0103ng l\u00ean m\u1ed9t c\u00e1ch ch\u1ecdn l\u1ecdc.<\/p>\n

      Ph\u01b0\u01a1ng ph\u00e1p th\u1ee9 ba l\u00e0 quang nhi\u1ec7t ph\u00e2n \u0111o\u1ea1n. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y l\u00e0 ph\u01b0\u01a1ng ph\u00e1p x\u1eed l\u00fd ch\u1ecdn l\u1ecdc ch\u1ec9 m\u1ed9t ph\u1ea7n kh\u00f4ng gian t\u1eeb l\u1ea7n chi\u1ebfu x\u1ea1 \u0111\u1ea7u ti\u00ean. Laser s\u1eed d\u1ee5ng quang nhi\u1ec7t ph\u00e2n \u0111o\u1ea1n l\u00e0 laser ph\u00e2n \u0111o\u1ea1n s\u1eed d\u1ee5ng Er: Glass ho\u1eb7c laser CO2. Nh\u01b0ng li\u1ec7u qu\u00e1 tr\u00ecnh quang nhi\u1ec7t ph\u00e2n \u0111o\u1ea1n ch\u1ec9 c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c v\u1edbi laser ph\u00e2n \u0111o\u1ea1n? Ph\u01b0\u01a1ng ph\u00e1p quang nhi\u1ec7t ph\u00e2n \u0111o\u1ea1n kh\u00f4ng ch\u1ec9 hi\u1ec7u qu\u1ea3 v\u1edbi laser ph\u00e2n \u0111o\u1ea1n \u0111\u1eaft ti\u1ec1n m\u00e0 c\u00f2n v\u1edbi ph\u01b0\u01a1ng ph\u00e1p pin-hole, b\u1eafn m\u1ed9t l\u1ea7n 1 tia b\u1eb1ng tia laser CO2 th\u00f4ng th\u01b0\u1eddng.<\/p>\n

      Lo\u1ea1i chi\u1ebfn l\u01b0\u1ee3c n\u00e0o n\u00ean \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng trong t\u1eebng t\u00ecnh hu\u1ed1ng? \u0110\u1ea7u ti\u00ean, l\u00fd thuy\u1ebft v\u1ec1 quang nhi\u1ec7t ch\u1ecdn l\u1ecdc ch\u1ee7 y\u1ebfu \u00e1p d\u1ee5ng cho c\u00e1c t\u00ecnh hu\u1ed1ng ngang. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng khi m\u00f4 \u0111\u00edch v\u00e0 m\u00f4 c\u1ea1nh tranh<\/p>\n

      n\u1eb1m theo chi\u1ec1u ngang. V\u00ed d\u1ee5, ph\u01b0\u01a1ng ph\u00e1p n\u00e0y \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111i\u1ec1u tr\u1ecb c\u00e1c s\u1eafc t\u1ed1 bi\u1ec3u b\u00ec nh\u01b0 \u0111\u1ed1m n\u00e2u. Th\u1ee9 hai, l\u00e0m m\u00e1t bi\u1ec3u b\u00ec \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng trong c\u00e1c t\u00ecnh hu\u1ed1ng th\u1eb3ng \u0111\u1ee9ng. V\u00ed d\u1ee5, n\u00f3 \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng khi \u0111i\u1ec1u tr\u1ecb c\u00e1c t\u1ed5n th\u01b0\u01a1ng l\u1edbp b\u00ec nh\u01b0 li\u1ec7u ph\u00e1p m\u1ea1ch m\u00e1u, tri\u1ec7t l\u00f4ng v\u00e0 tr\u1ebb h\u00f3a kh\u00f4ng x\u00e2m l\u1ea5n. Ph\u01b0\u01a1ng ph\u00e1p th\u1ee9 ba c\u00f3 th\u1ec3 \u00e1p d\u1ee5ng cho m\u1ecdi tr\u01b0\u1eddng h\u1ee3p.<\/p>\n

      Ng\u01b0\u1ee3c l\u1ea1i, t\u00ecnh hu\u1ed1ng n\u00e0o m\u00e0 c\u00e1c ph\u01b0\u01a1ng ph\u00e1p n\u00e0y c\u00f3 th\u1ec3 g\u00e2y ra v\u1ea5n \u0111\u1ec1? \u0110\u1ea7u ti\u00ean, trong l\u00fd thuy\u1ebft quang nhi\u1ec7t ch\u1ecdn l\u1ecdc, c\u00e1c v\u1ea5n \u0111\u1ec1 n\u1ea3y sinh khi h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 t\u01b0\u01a1ng t\u1ef1 ho\u1eb7c \u0111\u1ed9 d\u00e0i xung t\u01b0\u01a1ng t\u1ef1. V\u00ed d\u1ee5, r\u1ea5t kh\u00f3 \u0111i\u1ec1u tr\u1ecb khi da nguy\u00ean thu\u1ef7 s\u1eadm m\u00e0u do \u0111\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 c\u1ee7a da nguy\u00ean thu\u1ef7 v\u00e0 \u0111\u1ed1m n\u00e2u l\u00e0 kh\u00f4ng l\u1edbn. Ng\u01b0\u1ee3c l\u1ea1i, vi\u1ec7c \u0111i\u1ec1u tr\u1ecb g\u1eb7p nhi\u1ec1u kh\u00f3 kh\u0103n khi \u0111\u1ed1m n\u00e2u nh\u1eb9 v\u00e0 v\u00f9ng da nguy\u00ean th\u1ee7y c\u00f3 m\u00e0u s\u00e1ng do \u0111\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 h\u1ec7 s\u1ed1 h\u1ea5p th\u1ee5 c\u1ee7a da nguy\u00ean thu\u1ef7 v\u00e0 \u0111\u1ed1m n\u00e2u kh\u00f4ng l\u1edbn. Th\u1ee9 hai, trong vi\u1ec7c l\u00e0m m\u00e1t bi\u1ec3u b\u00ec, c\u00e1c v\u1ea5n \u0111\u1ec1 c\u00f3 th\u1ec3 ph\u00e1t sinh n\u1ebfu l\u00e0m m\u00e1t bi\u1ec3u b\u00ec k\u00e9m. B\u00e1c s\u0129 dung laser ph\u1ea3i lu\u00f4n ki\u1ec3m tra m\u00e1y l\u00e0m m\u00e1t. Th\u1ee9 ba, trong quang nhi\u1ec7t ph\u00e2n \u0111o\u1ea1n, c\u00e1c v\u1ea5n \u0111\u1ec1 n\u1ea3y sinh khi tia laser ph\u00e2n \u0111o\u1ea1n qu\u00e1 d\u00e0y \u0111\u1eb7c. Trong tr\u01b0\u1eddng h\u1ee3p n\u00e0y, vi\u1ec7c t\u00e1i t\u1ea1o t\u1eeb m\u00f4 b\u00ecnh th\u01b0\u1eddng t\u1edbi m\u00f4 \u0111\u01b0\u1ee3c chi\u1ebfu x\u1ea1 ph\u00e2n \u0111o\u1ea1n kh\u00f4ng d\u1ec5 d\u00e0ng v\u00e0 c\u00f3 th\u1ec3 g\u00e2y ra t\u00e1c d\u1ee5ng ph\u1ee5.<\/p>\n

      T\u00e0i li\u1ec7u tham kh\u1ea3o<\/h2>\n
        \n
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        CH\u01af\u01a0NG 3: C\u00c1C NGUY\u00caN L\u00dd QUAN TR\u1eccNG C\u1ee6A LASER Bi\u00ean d\u1ecbch: Bs. Tr\u01b0\u01a1ng T\u1ea5n Minh V\u0169 \u0110\u1ec3 t\u1ea3i file PDF C\u00e1c nguy\u00ean l\u00fd quan tr\u1ecdng c\u1ee7a laser, h\u00e3y click t\u1ea1i \u0111\u00e2y. L\u00fd thuy\u1ebft n\u00e2ng cao v\u1ec1 quang nhi\u1ec7t ch\u1ecdn l\u1ecdc Trong \u201cCh\u01b0\u01a1ng 1\u201d ch\u00fang ta \u0111\u00e3 xem x\u00e9t l\u00fd thuy\u1ebft quan tr\u1ecdng nh\u1ea5t li\u00ean quan […]\n","protected":false},"author":1,"featured_media":34029,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-34005","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-y-te-suc-khoe"],"acf":[],"_links":{"self":[{"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/posts\/34005","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/comments?post=34005"}],"version-history":[{"count":0,"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/posts\/34005\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/media\/34029"}],"wp:attachment":[{"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/media?parent=34005"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/categories?post=34005"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vnras.com\/drug\/wp-json\/wp\/v2\/tags?post=34005"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}