Fractionation effects in particle radiotherapy: implications for hypo-fractionation regimes
Fractionation effects in particle radiotherapy: implications for hypo-fractionation regimes
复制标题
DOI：
10.1088/0031-9155/55/19/005
复制
发表时间：
2010-10-07
影响因子：
3.5
通讯作者：
Paganetti, H.
中科院分区：
文献类型：
--
作者：
Carabe-Fernandez, A.;Dale, R. G.;Paganetti, H.
其目的是论证线性二次(LQ)模型中β参数的值变化对用于高线性能量转移(LET)放射治疗的临床相对生物有效性(RBE)值计算的潜在影响。在LQ公式中引入参数RBE(Min)，以考虑β辐射敏感性系数随LET的变化可能发生的变化。该模型用来拟合两种条件下的分馏数据，其中RBE(Min)=1和RBE(Min)不等于1。用非线性回归和方差分析检验了假设，即包含非单位值的RBE(Min)可以更好地预测从以前的文献中获得的各种组织的快中子、碳离子、介子和质子的分馏数据在较低分馏次数下所需的总等效剂量。对于中子，RBE(Min)不等于1的假设在89%的情况下提供了更好的拟合，而对于碳离子，RBE(Min)不等于1仅在展开的Bragg峰处提供了更好的拟合。这些结果提供了在计算临床上相关的RBE值时，特别是在使用高LET辐射的每部分高剂量(即低分馏)时，β参数的变化可能产生影响的证据。
The aim is to demonstrate the potential impact of changes in the value of the beta parameter in the linear quadratic (LQ) model on the calculation of clinical relative biological effectiveness (RBE) values used for high linear energy transfer (LET) radiotherapy. The parameter RBE(min) is introduced into the LQ formulation to account for possible changes in the beta radiosensitivity coefficient with changing LET. The model is used to fit fractionated data under two conditions, where RBE(min) = 1 and RBE(min) not equal 1. Nonlinear regression and analysis of variance are used to test the hypothesis that the inclusion of a non-unity value of RBE(min) better predicts the total iso-effective dose required at low number of fractions for fast neutrons, carbon ions, pi-meson and proton fractionation data obtained for various tissues from previous publications. For neutrons the assumption of RBE(min) not equal 1 provided a better fit in 89% of the cases, whereas for carbon ions RBE(min) not equal 1 provided a better fit only for normal tissue at the spread-out Bragg peak. The results provide evidence of the impact that variations in the beta parameter may have when calculating clinically relevant RBE values, especially when using high doses per fraction (i.e. hypofractionation) of high-LET radiations.