可见光LED的皮肤光疗应用综述

皮肤光疗是利用光线的辐射治疗皮肤类疾病或美容的治疗技术,其种类包括可见光、红外线、紫外线、激光、光化学疗法等方式。随着LED光源的发展,其在皮肤治疗领域的应用日趋广泛,其光源参数的选用对治疗效果的优劣也有着显著的影响,包括剂量、波长、照射模式等。本篇综述主要介绍了皮肤光疗的作用机制、应用领域以及光照时脉冲及连续参数的选用对治疗效果的影响。

脉冲LED黄光对皮肤细胞黑素生成的影响

低水平光疗法(LLLT)是治疗皮肤病的常用方法。目前,关于脉冲光照射是否优于连续光照射模式及其原因仍有待讨论。本文设计制作了脉冲黄光LED装置,使其在各种占空比下保持恒定的平均辐射照度。使用该装置比较了连续和脉冲光照对皮肤细胞黑素体成熟和黑色素合成的影响。实验分别检测了主要的生物学评估指标,包括TYR/TRP-1/MITF的细胞活力、酪氨酸酶活性,以及mRNA和蛋白质表达。实验结果表明,连续和脉冲LED光照均可抑制黑色素合成,其特征是TYR和TRP-1的mRNA和蛋白水平均显著降低。与连续模式相比,脉冲光模式对黑色素合成具有更好的抑制作用。

Comparison of photodynamic therapy for skin cancers and pre-cancers with δ-aminolevulinic acid

Objective:The aim of the study was to compare the effects of photodynamic therapy(PDT) with δ-aminolevulinic acid(ALA) for patients with different kinds of skin cancers and pre-cancers.Methods:The present study enrolled seventyfive cases,which included 17 cases of actinic keratosis(AK),9 cases of Bowen's disease,11 cases of superficial basal cell carcinomas(BCC),23 cases of nodule basal cell carcinomas and 15 cases of squamous cell carcinomas(SCC),and every patient had single lesion.All patients were treated with 20% ALA topically and He-Ne laser weekly for three times,and followed up 1-3 years.Results:After therapy,the rates of complete reaction(CR) were 100% in AK lesions,77.8% in Bowen's diseases,90.9% in superficial BCCs,47.8% in nodule BCCs,and 50.3% in SCCs,which had significant differences among these five kinds of lesions(H = 18.27,P < 0.05).The therapeutic effectiveness of ALA-PDT for AK was superior to that of Bowen's disease(Q = 4.364,P < 0.05),superficial BCC(Q = 5.55,P < 0.01),SCC(Q = 8.94,P < 0.01) and nodule BCC(Q = 17.91,P < 0.01);the effect of Bowen's disease was better than that of SCC(Q = 7.8,P < 0.01),nodule BCC(Q = 13.44,P < 0.01);the effect of superficial BCC was better than that of SCC(Q = 9.73,P < 0.01),nodule BCC(Q = 16.28,P < 0.01),but similar with Bowen's disease(Q = 0.96,P > 0.05);the effect of SCC was better than that of nodule BCC(Q = 17.74,P < 0.01).Conclusion:Our study shows that therapeutic effectiveness of ALA-PDT for AK is best in five diseases,and Bowen's disease and superficial BCC are secondary,while nodule BCC and SCC are at the bottom.

The impact of intensity modulated radiotherapy on the skin dose for deep seated tumors

Objective: The purpose of this study was to investigate the impact of intensity modulated radiotherapy (IMRT) on surface doses for brain, abdomen and pelvis deep located tumors treated with 6 MV photon and to evaluate the skin dose calculation accuracy of the XIO 4.04 treatment planning system. Methods: More investigations for the influences of IMRT on skin doses would increase its applications for many treatment sites. Measuring skin doses in real treatment situations would reduce the uncertainty of skin dose prediction. In this work a pediatric human phantom was covered by a layer of 1 mm bolus at three treatment sites and thermoluminescent dosimeter (TLD) chips were inserted into the bolus at each treatment site before CT scan. Two different treatment plans [three-dimensional conformal radiation therapy (3DCRT) and IMRT] for each treatment sites were performed on XIO 4.04 treatment planning system using superposition algorism. Results: The results showed that the surface doses for 3DCRT were higher than the surface doses in IMRT by 1.6%, 2.5% and 3.2% for brain, abdomen and pelvis sites respectively. There was good agreement between measured and calculated surface doses, where the calculated surface dose was 15.5% for brain tumor calculated with 3DCRT whereas the measured surface dose was 12.1%. For abdomen site the calculated surface dose for IMRT treatment plan was 16.5% whereas the measured surface dose was 12.6%. Conclusion: The skin dose in IMRT for deep seated tumors is lower than that in 3DCRT which is another advantage for the IMRT. The TLD readings showed that the difference between the calculated and measured point dose is negligible. The superposition calculation algorism of the XIO 4.04 treatment planning system modeled the superficial dose well.

Evaluation of photodynamic therapy of skin cancers with δ-aminolevulinic acid

Objective To use δ-aminolevulinic acid induced photodynamic therapy (ALA-PDT) increasingly in treating skin cancers and other diseases in many countries and to explore the efficacy of ALA-PDT for skin cancers in China. Methods Eighty-eight patients, including 34 cases of basal cell carcinoma (BCC), 32 cases of squamous cell carcinoma (SCC), two cases of basal-squamous cell carcinoma (BSCC), one case of verrucuous carcinoma, nine cases of Bowen disease, two cases Paget disease of the nipple and eight cases of extramammary Paget disease, were treated by the δ-aminolevulinic acid induced photodynamic therapy first in China from 1997 to 2000. Results All BCC, including 11 cases of superficial lesions and 29 solid lesions, achieved complete reaction (CR) by 1-4 times of the ALA-PDT. Except one patient with adenoid SCC (grade Ⅲ), all SCC (grade Ⅰ and grade Ⅱ) patients achieved complete remission by 3-6 times of ALA-PDT. All Bowen diseases achieved complete reaction by 1-4 times. Although for Paget diseases it could not cure the disease simply by ALA-PDT, it could control the symptoms. The recurrence rates were 11% (4/34) for BCC, and 22% (7/32) for SCC by following up 1-3 years after the therapy. The continuous therapy is still effective. Conclusions ALA-PDT is an effective, non-traumatic treatment for patients with BCC, SCC, Bowen and Paget diseases. It is especially suitable for older and weaker patients or those who are not tolerable to other therapies. It also has a unique advantage for tumors in specific anatomical areas. It is a new alternative modality for skin cancer therapies.