光动力疗法是一种利用激光、光敏剂发生光化学反应从而特异性杀灭肿瘤细胞的药械联合疗法。治疗的柔性光纤可随人体自然腔道的弯曲而弯曲，通过内窥镜活检通道，光纤能够到达腔内近距离照射肿瘤部位。内窥镜辅助光动力疗法因具有显著的局部疗效和微创治疗优势而被广泛应用于腔道恶性肿瘤的治疗中。本文介绍了光动力治疗肿瘤疾病的内窥镜技术的发展，提出了在实现术前诊断、术中可视、视场统一及诊疗一体等目标中存在的技术问题，并汇总了解决方案。本文概述了光动力诊疗内窥技术在腔道肿瘤诊疗中的临床应用现状，以期为光动力治疗的精准化发展提供参考。

光动力疗法是目前临床上出现的一种新型治疗肿瘤的方法, 利用光敏剂吸收可见-近红外光并在组织氧的参与下发生光化学反应, 产生活性氧物质进而诱导肿瘤细胞凋亡或坏死。光动力疗法对肿瘤侵袭性低, 具有较高的选择性和良好的患者依从性, 因此被广泛用于各种消化道恶性肿瘤的姑息性治疗和挽救性治疗。本文对近年来国内外应用光动力疗法治疗消化道肿瘤的文献进行综述, 对所报道的疾病类型、治疗病例数、光敏剂和光源、疗效和安全性等信息进行分类整理, 并对所面临的挑战和近期的研究进展进行了汇总, 以期全面和客观地了解光动力疗法在治疗消化道肿瘤中的应用和研究进展, 探讨目前的新应用及存在的问题和可能的发展方向。

5-氨基酮戊酸(ALA)是体表光动力疗法的一个重要前体药物, 通过代谢产物原卟啉Ⅸ(PpⅨ)介导发挥光敏作用。ALA制剂的研发和优化促生了一系列产品和技术, 不仅推动了体表光动力疗法的应用, 而且ALA介导的PpⅨ荧光还可用于肿瘤的荧光可视化和辅助手术。本文将对光动力诊疗中ALA及其酯类衍生物和PpⅨ的研究进展作一个系统介绍。

The detection of early gastric cancer that often develops asymptomatically is crucial for improving patient survival. The photodynamic diagnosis (PDD) of gastric cancer using 5-aminolevulinic acid/protoporphyrin IX (5-ALA/PpIX) has been reported in several studies. However, the selectivity of PDD of gastric tumor is poor with often false-positive results that require the development of new methods to improve PDD for early gastric cancer. Therefore, a measure of the complexity of gastric microcirculation (multi-scale entropy, MSE) and the detrended fluctuation analysis (DFA) were applied as additional tools to detect early gastric cancer in rats.In this experimental study, we used our original model of metastatic adenocarcinoma in the stomach of a rat. To induce a gastric tumor, we used a long-term combination (for 9 months, which is 1/2 of the life of rats) of two natural factors, such as chronic stress (overpopulation being typical for modern cities) and the daily presence of nitrites in food and drinks, which are common ingredients added to processed meat and fish to help preserve food. Our results clearly show that both methods, namely, PDD using 5-ALA/PpIX and complexity/correlation analysis, can detect early gastric cancer, which was confirmed by histological analysis. Pre-cancerous areas in the stomach were detected as an intermediate fluorescent signal or MSE level between normal and malignant lesions of the stomach. However, in some cases, PDD with 5-ALA/PpIX produced a false-positive fluorescence of exogenous fluorophores due to its accumulation in benign and inflammatory areas of the mucosa. This fact indicates that the PDD itself is not sufficient for the correct diagnosis of gastric cancer, and the use of additional characteristics, e.g., complexity measures or scaling exponents, can significantly improve the diagnostic accuracy of PDD of gastric cancer that should be confirmed in further clinical studies and applications.

局部外敷ALA和静脉注射小剂量HPD联合用药后进行激光光敏诊断和光动力学治疗,探讨这种联合用药光动力学疗法治疗皮肤恶性肿瘤的疗效。并与常规HPD-PDT及激光气化肿瘤合并ALA-PDT治疗作临床疗效对比。方法:30例患者,45处皮肤损害。采用ALA-PDT与小剂量HPD-PDT联合的方案进行治疗。光敏药物剂量:8%ALA 霜剂外敷,1.5mg/kg HPD静脉用药,波长630nm半导体激光照射(功率密度250mW/cm2,照射时间20分钟/光斑)。同时在PDT治疗过程中,及以后的随访中均以激光光敏诊断技术指导治疗及判断避光时间。并与常规HPD(5mg/kg)-PDT治疗皮肤恶性肿瘤43例及三周前激光气化肿瘤加20%ALA霜剂外敷光动力学治疗29例作疗效比较。结果:ALA联合小剂量HPD激光光动力学治疗组,除一例鳞癌II级患者及一例恶性黑色素瘤患者出现复发外,其余患者对联合治疗的效果均佳,随访6～24月,均获得了痊愈,近期痊愈率93.33%,显效率6.67%,皮肤避光时间减少到10～14天。HPD-PDT治疗皮肤恶性肿瘤组43例,40例达近期痊愈,近期痊愈率91.43%,3例显效,显效率8.57%(显效3例,2例为色素型基底细胞癌,1例为直肠癌肛周复发)。激光气化肿瘤加ALA-PDT治疗组29例,26例一次治疗痊愈,近期痊愈率89.66%,3例显效,显效率10.34%(显效3例,2例鳞癌II级经二次治疗痊愈,1例汗管癌7周复发改用手术治疗)。结论:1.ALA联合小剂量HPD的光动力学疗法对于诊断和治疗皮肤恶性肿瘤有较佳的疗效。两种光敏剂的联合使用,使皮肤避光时间由原来常规剂量HPD-PDT所必需的4~5周缩短到2周左右,并改善了ALA-PDT作用深度浅(2mm)的弊端。2.光敏诊断是一种简便、快捷、灵敏、非创伤性的肿瘤诊断方法,对于提高肿瘤的早期诊断率有很大意义,又能作为判断避光时间的辅助手段。3.光动力学治疗是一种对肿瘤组织杀伤具有高度选择性的微创技术,病人对整个治疗过程的耐受性好,更适合于年老体弱或对皮肤美观有特殊需求的患者。