Campbell C Louise, Brown C Tom A, Wood Kenneth, Salvio Ana Gabriela, Inada Natalia M, Bagnato Vanderlei S, Moseley Harry
SUPA, School of Physics and Astronomy, University of St Andrews, UK.
Skin Department of Amaral Carvalho Hospital, Brazil.
Photodiagnosis Photodyn Ther. 2017 Jun;18:204-207. doi: 10.1016/j.pdpdt.2017.02.004. Epub 2017 Feb 28.
Topical photodynamic therapy (PDT) is a non-invasive light based therapy used to treat non-melanoma skin cancer (NMSC) and dysplasia. During PDT, the light sensitive molecule protoporphyrin IX (PpIX) is activated, resulting in the production of singlet oxygen, which subsequently leads to cell death. PpIX is metabolised from a topically applied pro-drug and the strong fluorescence signal associated with PpIX can be utilised as an indicator of the amount of PpIX present within the tumour tissue. In this work we measure the build up PpIX during the occlusive treatment phase and investigate how the PpIX production rate is affected by different lesion and patient characteristics.
Fluorescence measurements were used to investigate the build up of PpIX within the tumour tissue during the 3h long occlusive treatment prior to irradiation. The study included in vivo measurements of 38 lesions from 38 individual patients. Actinic keratosis (AK) and basal cell carcinoma (BCC) were the lesion types included in this study. The resulting data from the study was analysed using generalised linear mixed effects models.
It was found that the surface fluorescence signal linearly increased with occlusive treatment time. The predictive models suggest that there is a significant difference in PpIX production between lesion location, however no significant difference is demonstrated between different lesion types, gender and skin type.
The study extends and supports previous knowledge of PpIX production during the occlusive treatment phase.
局部光动力疗法（PDT）是一种用于治疗非黑色素瘤皮肤癌（NMSC）和发育异常的非侵入性光基疗法。在PDT过程中，光敏分子原卟啉IX（PpIX）被激活，产生单线态氧，随后导致细胞死亡。PpIX由局部应用的前体药物代谢而来，与PpIX相关的强荧光信号可作为肿瘤组织中PpIX含量的指标。在这项工作中，我们测量了封闭治疗阶段PpIX的积累，并研究了PpIX产生率如何受到不同病变和患者特征的影响。
在照射前3小时的封闭治疗期间，使用荧光测量来研究肿瘤组织中PpIX的积累。该研究包括对38名个体患者的38个病变进行体内测量。光化性角化病（AK）和基底细胞癌（BCC）是本研究中包含的病变类型。使用广义线性混合效应模型分析该研究的结果数据。
发现表面荧光信号随封闭治疗时间线性增加。预测模型表明，病变位置之间PpIX的产生存在显著差异，然而不同病变类型、性别和皮肤类型之间未显示出显著差异。
该研究扩展并支持了先前关于封闭治疗阶段PpIX产生的知识。
