Evaluating the biologically effective dose (BED) concept using a dynamic tumor simulation model
Evaluating the biologically effective dose (BED) concept using a dynamic tumor simulation model
复制标题
DOI：
10.1002/mp.14228
复制
发表时间：
2020-06-08
期刊：
影响因子：
3.8
通讯作者：
Watanabe, Yoichi
中科院分区：
文献类型：
--
作者：
Dahlman, Erik L.;Watanabe, Yoichi
目的用多群体反应扩散模拟方法对生物有效剂量（BED）的3种计算公式进行评价，以确定3种公式在不同治疗方案下的效果是否相同。方法对标准BED公式（BED）进行更新，建立BED phi和BED phi T两个新公式，以考虑剂量的空间不均匀性和组分间的细胞再生。这些BED公式用于计算两次、三次和五次分次治疗的剂量/分次值，并将这些治疗的肿瘤体积与单次分次治疗的肿瘤体积进行比较。基于反应扩散方程的球形肿瘤模型用于计算递送第一部分后185天每个肿瘤的最终体积。单组分和多组分治疗之间的体积的百分比差异被用来作为一种措施，以测试每个BED formulation.Results的准确性之间的体积的百分比差异单组分和多组分治疗方案变化高达约18.5%，如果每部分的剂量计算使用床，但所提供的剂量是不均匀的。适当应用空间不均匀性的剂量和肿瘤再生校正因子修改剂量每分数值不超过5%，但导致模拟肿瘤体积的改善下降到约2%或更低的差异volume.Conclusions治疗方案具有相同的BED值应具有相同的效果。然而，当不均匀地递送剂量时或当忽略分次之间的肿瘤再生长时，在多分次治疗中递送的每一分次剂量的微小变化可能对治疗的肿瘤体积具有较大影响。纳入这些校正因子对于以下基本假设很重要：相同BED的治疗对临床观察到的肿瘤体积具有相同的影响。
Purpose To evaluate three different formulae for calculating the biologically effective dose (BED) by use of a multipopulation reaction-diffusion simulation to determine whether these formulae produce equivalent effects for different treatment regimes.Methods The standard BED formula, BEDs, was updated to account both for spacial nonuniformity in dose and for cellular regrowth between fractions, by creating two new formulae: BED phi and BED phi T. These BED formulae were used to calculate dose per fraction values for two, three, and five fraction treatments and to compare the tumor volumes of those treatments to those of a single fraction. A spherical tumor model based on the reaction-diffusion equation was used to calculate the final volume of each tumor 185 days after the delivery of the first fraction. The percent difference in volume between single-fraction and multiple-fraction treatments was used as a measure to test the accuracy of each BED formula.Results Percent differences in volume between single- and multiple-fraction treatment regimes varied up to approximately 18.5% if the dose per fraction was calculated using BEDs but the delivered dose was nonuniform. Proper application of spacial nonuniformity in dose and tumor regrowth correction factors modified the dose per fraction values by no more than 5%, but resulted in the improvement of simulated tumor volumes down to around 2% or lower difference in volume.Conclusions Treatment regimes with the same BED value should have the same effect. However, small changes in the dose per fraction delivered in multiple-fraction treatments can have a large effect on the tumor volume of a treatment when the dose is delivered nonuniformly or when tumor regrowth between fractions is ignored. Inclusion of these correction factors is important for the underlying assumption that treatments with equal BED will have equal effects on the clinically observed tumor volume.