LIOB in Picosecond laser

최근 picosecond laser를 이용한 LIOB가 hot issue입니다.
Picosecond Nd:YAG laser는 원래 색소 치료를 target으로 개발되었으나 최근에 fractional mode를 이용해서 rejuvenation에 활용하는 기술이 LIOB가 되겠습니다.
Laser-Induced Optical Breakdown (LIOB)이론은 간단하게 설명드리면 다음과 같습니다.
Sub-nanosecond pulse duration의 적외선을 focused beam을 조사 시 multiphoton에 의해 cavitation과 함께 plasma가 발생하게 됩니다.
이때 표피는 보호하면서 표피 하부에 subcision like한 현상이 생기는 것으로 이를 통해 new collagen이 생성되고 rejuvenation의 결과를 얻을 수 있다는 것이 핵심 이론이 되겠습니다.
 
▶Concepts of Laser-Induced Optical Breakdown (LIOB)
--> new indication for the rejuvenation with fractional mode of picosecond laser
--> Dual effect of picosecond laser: Bleaching & Rejuvenation
 
▶Principles of Laser-Induced Optical Breakdown (LIOB)
Tightly focused near-infrared laser pulses  (sub-nanosecond pulse of 1064 nm)
--> create optical breakdown in the dermis while leaving the fully intact epidermis
resulting in cavitation and plasma generation by multiphoton
explosive vaporization and mechanical expansion in the dermis 
--> this stimulates a healing response of dermis
--> consequently skin remodeling
resulting in skin rejuvenation effects

▶Advantages:
1) no or little social down-time 
2) efficacy: comparable to conventional fractional ablative techniques
3) safe, breakthrough treatment procedure for skin rejuvenation without damaging the epidermis

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Minimally invasive non-thermal laser technology using laser-induced optical breakdown for skin rejuvenation

J. Biophotonics 5, No. 2, 194–199 (2012)

Louis Habbema1, Rieko Verhagen2, Robbert Van Hal2, Yan Liu2, and Babu Varghese*; 2

1 Department of Dermatology, Medisch Centrum ’t Gooi, Bussum, The Netherlands
2 Care and Health Applications group, Philips Research Europe, High Tech Campus 34, 5656 AE Eindhoven, The Netherlands

We describe a novel, minimally invasive laser technology for skin rejuvenation by creating isolated microscopic lesions within tissue below the epidermis using laser induced optical breakdown. Using an in-house built prototype device, tightly focused near-infrared laser pulses are used to create optical breakdown in the dermis while leaving the epidermis intact, resulting in lesions due to cavitation and plasma explosion. This stimulates a healing response and consequently skin remodelling, resulting in skin rejuvenation effects. Analysis of ex-vivo and in-vivo treated human skin samples successfully demonstrated the safety and effectiveness of the microscopic lesion creation inside the dermis. Treatments led to mild side effects that can be controlled by small optimizations of the optical skin contact and treatment depth within the skin. The histological results from a limited panel test performed on five test volunteers show evidence of microscopic lesion creation and new collagen formation at the sites of the optical breakdown. This potentially introduces a safe, breakthrough treatment procedure for skin rejuvenation without damaging the epidermis with no or little social down-time and with efficacy comparable to conventional fractional ablative techniques.