Should single or distributed parameters be used to explain the steepness of tumour control probability curves?
Should single or distributed parameters be used to explain the steepness of tumour control probability curves?
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DOI：
10.1088/0031-9155/48/3/308
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发表时间：
2003-02-07
影响因子：
3.5
通讯作者：
Fowler, JF
中科院分区：
文献类型：
--
作者：
Dasu, A;Toma-Dasu, I;Fowler, JF
线性二次(LQ)模型可以方便地比较放射治疗中不同的分割计划。然而，估计单一分步处理的辐射效应会引起许多关于建模过程中使用的参数的问题。几项研究已经使用肿瘤控制概率(TCP)曲线来推导LQ参数的值，这些值可进一步用于治疗计划的分析和排序。不幸的是，很少有人注意到这些衍生参数的生物学相关性，无论是细胞的初始数量还是其固有的辐射敏感性，或者两者兼而有之。本文研究了Tcp参数的单值与所得到的剂量-效应曲线之间的关系。该模型研究的结果表明，仅通过选择参数的极值(如果它们是单值)，才能解释临床上对tcp曲线的位置和陡度的观察。这些极值与实验观测结果相矛盾。这一矛盾表明，参数的单一值不太可能合理地解释临床观察，应该考虑输入参数的某些分布。
Linear quadratic (LQ) modelling allows easy comparison of different fractionation schedules in radiotherapy. However, estimating the radiation effect of a single fractionated treatment introduces many questions with respect to the parameters to be used in the modelling process. Several studies have used tumour control probability (TCP) curves in order to derive the values for the LQ parameters that may be used further for the analysis and ranking of treatment plans. Unfortunately, little attention has been paid to the biological relevance of these derived parameters, either for the initial number of cells or their intrinsic radiosensitivity, or both. This paper investigates the relationship between single values for the TCP parameters and the resulting dose-response curve. The results of this modelling study show how clinical observations for the position and steepness of the TCP curve can be explained only by the choice of extreme values for the parameters, if they are single values. These extreme values are in contradiction with experimental observations. This contradiction suggests that single values for the parameters are not likely to explain reasonably the clinical observations and that some distributions of input parameters should be taken into consideration.