鉺雅克雷射(Er:YAG laser)簡介


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鉺雅克雷射(Er:YAG laser)簡介

皮膚科  王修含 醫師

    在皮膚科眾多的雷射之中,鉺雅克雷射(Erbium: YAG laser,亦有人翻譯作「鉺雅各」雷射、「鉺雅鉻」雷射)是最基本的皮膚科治療用雷射,可應用於點痣、除斑、治療痘疤、磨皮、去除皮膚腫瘤……等治療。鉺雅克雷射與二氧化碳雷射(CO2 laser)皆為「剝離式」(ablative)的汽化型雷射,亦即藉由汽化皮膚內部的水份,由表層至深層逐層剝離皮膚組織,達到破壞病灶的目的。

    鉺雅克雷射的名稱由來,是因為這種雷射的光源來自「鉺雅克晶體」(Er:YAG crystal)。鉺雅克晶體(Er:Y3Al5O12) 是以稀土元素「鉺」(Er, erbium),以大約50%的濃度摻入「釔鋁石榴石」(YAG, yttrium aluminium garnet, Y3Al5O12) 晶體形成的一種人造結晶材料。附帶一提,皮膚科另一種「釹雅克雷射」(Nd:YAG laser),例如常用的「C6淨膚雷射」,則是利用摻有釹元素的YAG晶體發出波長1064nm的雷射(「釹雅克雷射」有時會誤寫為「銣雅克雷射」、「銣雅鉻雷射」)。


圖:鉺雅各雷射(Er:YAG laser)晶體成份–「鉺(Er, Erbium)」金屬的外觀
(原圖引用自http://en.wikipedia.org/wiki/File:Erbium-crop.jpg)

    若以波長介於600至800 nm之間的閃光燈趨動鉺雅克晶體,可激發出波長2940 nm的紅外線雷射光,即為鉺雅克雷射。由於原子共振(atomic resonances)的緣故,水分子對於這個波長的能量吸收度甚高,而且一般組織內的水份約佔70%的體積,因此鉺雅克雷射照射至皮膚後,可讓皮膚內的水分子吸收,在達到攝氏100度的溫度後,形成汽化狀態,進而移除該部位的組織。

    除了水分子,鉺雅克雷射的波長也會被氫氧基磷灰石(hydroxyapatite)所吸收,這種物質為人體骨骼中的主要成份之一,因此鉺雅克雷射亦可用於切割骨骼組織或牙齒。除了在皮膚科治療方面具有重要角色,鉺雅克雷射也是牙科的重要雷射工具。

    皮膚科常用的鉺雅克雷射廠牌繁多,以Fotona XS Dualis Er:YAG laser為例,其參數如下
波長(Laser wavelength):     2940 nm
最大脈衝能量(Max. pulse energy):     3000 mJ
最大平均功率(Max. average power):     20 W
最大頻率(Max. frequency):     20 Hz
光點直徑(Spot sizes):  0.5 to 12 mm
脈衝寬度(Pulsewidth):    
      VSP Mode: 100 microseconds
      SP Mode: 300 microseconds
      LP Mode: 600 microseconds
      XLP Mode: 1500 microseconds

Fotona XS Dualis鉺雅克雷射的特點,在於可藉由改變不同的脈衝寬度,調整鉺雅克雷射的穿透深度與產生的熱效應,並可外接點陣式的掃描器,產生飛梭化的能量輸出,可進行鉺雅克波長的飛梭式治療。

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以Fraxel飛梭雷射強化毛囊再生

賀!生髮新研究發表:以Fraxel飛梭雷射強化毛囊再生之研究論文

 

台大皮膚科與台大醫學工程研究所林頌然教授團隊新發表的研究題目:
以非剝離式飛梭雷射(即台灣俗稱的Fraxel二代飛梭雷射)強化毛囊再生功能
獲刊登於Lasers in Surgery and Medicine期刊。

王修含醫師有幸參與此研究,特將此論文摘要附錄於下:

 

 

Lasers Surg Med. 2015 Apr;47(4):331-41. doi: 10.1002/lsm.22330. Epub 2015 Apr 10.

 

Enhancing hair follicle regeneration by nonablative fractional laser: Assessment of irradiation parameters and tissue response.

 

 

Authors: Yueh‐Feng Wu, Shiou‐Han Wang, Pei‐Shan Wu, Sabrina Mai‐Yi Fan, Hsien‐Yi Chiu, Tsung‐Hua Tsai, Sung‐Jan Lin
作者:吳岳峰, 王修含, 吳佩珊, 范邁儀, 邱顯鎰, 蔡宗樺, 林頌然

 

 

Background and Objective

Identification of methods to enhance anagen entry can be helpful for alopecia. Recently, nonablative laser has been proposed as a potential treatment for alopecia. However, how the laser parameters affect stem cell activity, hair cycles and the associated side effects have not been well characterized. Here we examine the effects of irradiation parameters of 1,550-nm fractional laser on hair cycles.

Study Design/Materials and Methods

The dorsal skin of eight-week-old female C57BL/6 mice with hair follicles in synchronized telogen was shaved and irradiated with a 1,550-nm fractional erbium-glass laser (Fraxel RE:STORE (SR1500) Laser System, Solta Medical, U.S.A.) with varied beam energies (5–35 mJ) and beam densities (500–3500 microthermal zones/cm2). The cutaneous changes were evaluated both grossly and histologically. Hair follicle stem cell activity was detected by BrdU incorporation and changes in gene expression were quantified by real-time PCR.

Results

Direct thermal injury to hair follicles could be observed early after irradiation, especially at higher beam energy. Anagen induction in the irradiated skin showed an all-or-non change. Anagen induction and ulcer formation were affected by the combination of beam energy and density. The lowest beam energy of 5 mJ failed to promote anagen entry at all beam densities tested. As beam energy increased from 10 mJ to 35 mJ, we found a decreasing trend of beam density that could induce anagen entry within 7–9 days with activation of hair follicle stem cells. Beam density above the pro-regeneration density could lead to ulcers and scarring followed by anagen entry in adjacent skin. Analysis of inflammatory cytokines, including TNF-α, IL-1β, and IL-6, revealed that transient moderate inflammation was associated with anagen induction and intense prolonged inflammation preceded ulcer formation.

 

Fig. 1. Laser irradiation. A. The skin on sides of the trunk was firmly stretched and irradiated with

a 1,550nm fractional erbium-glass laser. B. The red rectangle indicated the irradiated area. C.

Schematic diagram of the post-natal synchronized hair cycles on the back of C57BL/6 mice. The

second telogen started at week 7 and persisted for about 5 weeks. Laser irradiation was performed

on week 8. M: morphogenesis; C: catagen; T: telogen; A: anagen.

 
Fig. 2. Laser beam energy and MTZ. Irradiated skin was sampled 1 day after irradiation. A.
Histology. MTZ could be identified by denatured collagen that showed a homogenized bluish
change. H&E staining. Bar¼100 mm. B. There was an increasing trend of the depth of MTZ as
beam energy was elevated. *P<0.05 compared with 5mJ group (N¼5). C. There was an
increasing trend of the width of MTZ as beam energy was elevated. *P<0.05 compared with 5mJ
group (N¼5).

 

Fig. 3. The effect of laser irradiation parameters on anagen induction and ulcer formation. A. Laser

beam energy was increased from 5 to 35mJ and laser beam density was increased from 500 to

3500MTZ/cm2. Yellow color indicated the therapeutic window in which premature anagen was

induced without ulcer formation. B. Quantification of the dynamics of anagen entry at various

irradiation parameters. P<0.05 compared with day 0 (N=5) in each group. 80103mm.

 

 

Fig. 4. Changes of skin and hair cycles. Laser beam energy was 15 mJ. At beam density of 552 MTZ/

cm2, no premature anagen entry was induced. At beam density of 1048MTZ/cm2, irradiated skin

started to turn grayish on day 9 to day 11(blue arrow head), indicating initiation of anagen. No skin

erosion or ulcer was observed. At beam density of 1600MTZ/cm2 and 2010MTZ/cm2, an ulcer

developed in the center of irradiated skin on day 5 and day 7 respectively (red arrow head).

Premature anagen entry surrounding the scar tissue was observed (yellow arrow head).

 

Fig. 5. Histological changes during hair cycle progression. Beam energy was 15mJ and beam

density was 1048MTZ/cm2. A. Comparison of gross skin change and histology. H&E staining.

Bar?100mm. B. Quantification of anagen entry area. * P<0.05 compared with day 0 (N=5). C.

Quantification of hair follicle length. * P<0.05 compared with day 0 (N=5).

 

Fig. 6(A). Dynamic changes of cell proliferation in hair follicles. Beam energy was 15mJ and beam

density was 1048MTZ/cm2. A. Double staining for BrdU and p-cadherin.

 

 

Fig. 6(B). Dynamic changes of cell proliferation in hair follicles. Beam energy was 15mJ and beam

density was 1048MTZ/cm2. A. Double staining for BrdU and p-cadherin. B. Double staining for

BrdU and K15. Secondary hair germ was positive for p-cadherin and HFSC was identified by K15.

From day 1 to day 5, BrdU was positive above bulge (yellow arrow heads). On day 7, BrdU was

positive in secondary hair germ to lower bulge (white arrow heads). On day 9 and day 11, BrdU was positive in bulge (red arrow heads). Many BrdU positive cells could be found in the hair matrix on day 9 to day 13 (green arrow heads). DP: dermal papilla; SG: secondary hair germ; BG: bulge.

Bar=50mm.

 

Fig. 7. Expression of IL-6 (A), TNF-a (B), and IL-1b (C) after laser

irradiation of varied beam densities. Laser beam energy was

15 mJ. At beam density of 552 MTZ/cm2, very slight increase of IL-

6, TNF-a, and IL-1b was detected after irradiation. At beam

density of 1048MTZ/cm2, a moderate increase of IL-6, TNF-a, and

IL-1b was observed from day 1 to day 3. At beam density of

1600MTZ/cm2, prolonged and higher levels of IL-6, TNF-a, and

IL-1b were observed.

 

Conclusion

To avoid side effects of hair follicle injury and scarring, appropriate combination of beam energy and density is required. Parameters outside the therapeutic window can result in either no anagen promotion or ulcer formation.

Keywords:

  • alopecia;
  • 1,550-nm erbium glass laser;
  • hair follicle regeneration;
  • stem cell;
  • inflammation

Lasers Surg. Med. 47:331–341, 2015. © 2015 Wiley Periodicals, Inc.

 

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