Begnozzi L, Gentile F P, Di Nallo A M, Chiatti L, Zicari C, Consorti R, Benassi M
Laboratorio Fisica Medica e Sistemi Esperti, C. R. S. Istituto Regina Elena per lo Studio e la Cura dei Tumori, Roma, Italy.
Strahlenther Onkol. 1994 Oct;170(10):590-4.
Since volumetric dose distributions are available with 3-dimensional radiotherapy treatment planning they can be used in statistical evaluation of response to radiation. This report presents a method to calculate the influence of dose inhomogeneity and fractionation in normal tissue complication probability evaluation.
The mathematical expression for the calculation of normal tissue complication probability has been derived combining the Lyman model with the histogram reduction method of Kutcher et al. [14] and using the normalized total dose (NTD) instead of the total dose.
The fitting of published tolerance data, in case of homogeneous or partial brain irradiation, has been considered. For the same total or partial volume homogeneous irradiation of the brain, curves of normal tissue complication probability have been calculated with fraction size of 1.5 Gy and of 3 Gy instead of 2 Gy, to show the influence of fraction size. The influence of dose distribution inhomogeneity and alpha/beta value has also been simulated: considering alpha/beta = 1.6 Gy or alpha/beta = 4.1 Gy for kidney clinical nephritis, the calculated curves of normal tissue complication probability are shown.
Combining NTD calculations and histogram reduction techniques, normal tissue complication probability can be estimated taking into account the most relevant contributing factors, including the volume effect.
由于三维放射治疗治疗计划可提供体积剂量分布，因此可用于对放射反应进行统计评估。本报告提出了一种在正常组织并发症概率评估中计算剂量不均匀性和分割方式影响的方法。
将莱曼模型与库彻等人[14]的直方图缩减方法相结合，并使用归一化总剂量（NTD）而非总剂量，推导出了计算正常组织并发症概率的数学表达式。
考虑了在均匀或部分脑照射情况下已发表的耐受数据的拟合情况。对于相同总体积或部分体积的均匀脑照射，计算了分次剂量为1.5 Gy和3 Gy而非2 Gy时的正常组织并发症概率曲线，以显示分次剂量的影响。还模拟了剂量分布不均匀性和α/β值的影响：对于肾脏临床肾炎，考虑α/β = 1.6 Gy或α/β = 4.1 Gy，给出了计算得到的正常组织并发症概率曲线。
结合NTD计算和直方图缩减技术，可以在考虑包括体积效应在内的最相关影响因素的情况下估计正常组织并发症概率。
