Inter-comparison of relative stopping power estimation models for proton therapy
Inter-comparison of relative stopping power estimation models for proton therapy
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DOI：
10.1088/0031-9155/61/22/8085
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发表时间：
2016-11-21
影响因子：
3.5
通讯作者：
Seco, Joao
中科院分区：
文献类型：
--
作者：
Doolan, P. J.;Collins-Fekete, Charles-Antoine;Seco, Joao
对于文献中的各种组织和组织替代材料，对Bichsel、Janni、ICRU和Schneider相对阻止力（RSP）估计模型的理论阻止力值进行了相互比较。11个塑料组织替代品的RSP测量使用布拉格峰移测量在水中，以建立一个黄金标准的RSP值特定于我们中心的质子束特性。基于文献组成计算理论组织替代物RSP值，以评估四种不同的计算方法。Bichsel/Janni/ICRU方法导致RSP的平均误差分别为-0.1/+0.7/-0.8%。使用施耐德方法时的误差，与I值从Bichsel，Janni和ICRU来源，遵循相同的模式，但一般较大。在此之后，优化平均元素电离能，直到理论RSP值之间的差异匹配测量。在将Schneider技术应用于72种人体组织时，如果未使用优化的I值，则在使用Bichsel/Janni/ICRU I值时，RSP中的误差可能分别高达-1.7/+ 1.1/-0.4%。因此，可能有必要在当前的化学计量校准程序中引入额外的步骤，其中在质子束中测量组织插入物RSP。然后可以优化元素I值以匹配这些测量值，从而降低计算人体组织RSP时的不确定性。
Theoretical stopping power values were inter-compared for the Bichsel, Janni, ICRU and Schneider relative stopping power ( RSP) estimation models, for a variety of tissues and tissue substitute materials taken from the literature. The RSPs of eleven plastic tissue substitutes were measured using Bragg peak shift measurements in water in order to establish a gold standard of RSP values specific to our centre's proton beam characteristics. The theoretical tissue substitute RSP values were computed based on literature compositions to assess the four different computation approaches. The Bichsel/Janni/ICRU approaches led to mean errors in the RSP of -0.1/+0.7/-0.8%, respectively. Errors when using the Schneider approach, with I-values from the Bichsel, Janni and ICRU sources, followed the same pattern but were generally larger. Following this, the mean elemental ionisation energies were optimized until the differences between theoretical RSP values matched measurements. Failing to use optimized I-values when applying the Schneider technique to 72 human tissues could introduce errors in the RSP of up to -1.7/+ 1.1/-0.4% when using Bichsel/Janni/ICRU I-values, respectively. As such, it may be necessary to introduce an additional step in the current stoichiometric calibration procedure in which tissue insert RSPs are measured in a proton beam. Elemental I-values can then optimized to match these measurements, reducing the uncertainty when calculating human tissue RSPs.