Kulyk Olena, Ibbotson Sally H, Moseley Harry, Valentine Ronan M, Samuel Ifor D W
Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, The University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK.
The Photobiology Unit, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK; The Scottish Photodynamic Therapy Centre, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK.
Photodiagnosis Photodyn Ther. 2015 Dec;12(4):630-9. doi: 10.1016/j.pdpdt.2015.10.002. Epub 2015 Oct 20.
Topical Photodynamic therapy (PDT) is an effective treatment for superficial non-melanoma skin cancers (NMSC) and dysplasia. During PDT light activates the photosensitiser (PpIX), metabolised from a topical pro-drug. A combination of PpIX, light and molecular oxygen results in inflammation and cell death. However, the outcomes of the treatment could be better. Insufficient biosynthesis of PpIX may be one of the causes of incomplete response or recurrence. Measuring surface fluorescence is usually employed as a means of studying PpIX formation. The aim of this work was to develop a device and a method for convenient fluorescence imaging in clinical settings to gather information on PpIX metabolism in healthy skin and NMSC with a view to improving PDT regimes.
A handheld fluorescence camera and a time course imaging method was developed and used in healthy volunteers and patients diagnosed with basal cell carcinoma (BCC) and actinic keratosis (AK). The photosensitiser (precursor) creams used were 5-aminolaevulinic acid (ALA; Ameluz(®)) and methyl aminolevulinate (MAL; Metvix(®)). Pain was assessed using a visual analogue score immediately after the PDT.
Fluorescence due to PpIX increases over three hours incubation in healthy skin and in lesional BCC and AK. Distribution of PpIX fluorescence varies between the lesion types and between subjects. There was no significant correlation between PpIX fluorescence characteristics and pro-drug, diagnosis or pain experienced. However, there was a clear dependence on body site.
The device and the method developed can be used to assess the characteristics of PpIX fluorescence, quantitative analysis and time course. Our findings show that body site influences PpIX fluorescence which we suggest may be due to the difference in skin temperature at different body sites.
局部光动力疗法（PDT）是治疗浅表性非黑素瘤皮肤癌（NMSC）和发育异常的有效方法。在PDT过程中，光激活由局部前体药物代谢产生的光敏剂（PpIX）。PpIX、光和分子氧共同作用导致炎症和细胞死亡。然而，该治疗的效果仍可进一步提高。PpIX生物合成不足可能是治疗反应不完全或复发的原因之一。测量表面荧光通常被用作研究PpIX形成的一种手段。本研究的目的是开发一种设备和方法，以便在临床环境中进行便捷的荧光成像，收集健康皮肤和NMSC中PpIX代谢的信息，从而改进PDT方案。
开发了一种手持式荧光相机和一种时间进程成像方法，并应用于健康志愿者以及被诊断为基底细胞癌（BCC）和光化性角化病（AK）的患者。使用的光敏剂（前体）乳膏为5-氨基乙酰丙酸（ALA；Ameluz®）和甲基氨基乙酰丙酸（MAL；Metvix®）。在PDT结束后立即使用视觉模拟评分法评估疼痛程度。
在健康皮肤、BCC病灶和AK病灶中，孵育三小时后，PpIX产生的荧光增强。PpIX荧光的分布在不同病灶类型和不同受试者之间存在差异。PpIX荧光特征与前体药物、诊断或疼痛程度之间无显著相关性。然而，其明显依赖于身体部位。
所开发的设备和方法可用于评估PpIX荧光的特征、定量分析和时间进程。我们的研究结果表明，身体部位会影响PpIX荧光，我们认为这可能是由于不同身体部位皮肤温度存在差异所致。
