A theoretical study of light fractionation and dose-rate effects in photodynamic therapy
A theoretical study of light fractionation and dose-rate effects in photodynamic therapy
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DOI：
10.2307/3579621
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发表时间：
1997-05-01
影响因子：
3.4
通讯作者：
Hasan, T
中科院分区：
文献类型：
--
作者：
Pogue, BW;Hasan, T
光动力疗法的功效取决于光的光剂量率或光的分级时间表。这些效应被认为受到氧气从毛细血管扩散所需的时间的限制，因为这种疗法消耗氧气的速度比供应到远离血管的组织的速度更快，通过代谢和光化学机制对氧气扩散和消耗进行建模，以将理论预测与不同光分馏和输送剂量率的实验结果进行比较，数学的问题已经在文献中描述，本研究扩展这些计算，以允许更直接和定量比较分馏实验，使用分析和数值参数，发现最佳分馏时间仅取决于毛细管间距，而不是照射强度或光敏剂浓度，计算表明，实验观察到的30和60 s的最佳分级时间对应于从毛细血管到细胞的距离约为1 mm，这些结果表明分级光照射实验需要仔细解释，并讨论了最佳分级时间较长的一些可能原因，（C）1997年，辐射研究学会。
The efficacy of photodynamic therapy is dependent upon the optical dose rate or upon the fractionation schedule of the light, These effects are thought to be limited by the time required for oxygen diffusion from the capillaries, since this therapy can consume oxygen faster than it can be supplied to tissues distant from the blood vessels, Oxygen diffusion and consumption by metabolic and photochemical mechanisms have been modeled here to compare theoretical predictions with experimental results of varying light fractionations and delivered dose rates, The mathematics of the problem have been described in the literature, and the present study extends these calculations to allow a more direct and quantitative comparison with fractionation experiments, using both analytical and numerical arguments, The optimum fraction time was found to depend only on the intercapillary spacing and not on the intensity of irradiation or the concentration of photosensitizer, The calculations indicate that experimentally observed optimum fractionation times of 30 and 60 s correspond to a distance from capillary to cell of approximately 1 mm, These results suggest that the fractionated light irradiation experiments need careful interpretation, and some possible reasons for longer optimum fractionation times are discussed, (C) 1997 by Radiation Research Society.