Experimental verification and clinical implementation of a commercial Monte Carlo electron beam dose calculation algorithm.
Experimental verification and clinical implementation of a commercial Monte Carlo electron beam dose calculation algorithm.
复制标题
商业蒙特卡罗电子束剂量计算算法的实验验证和临床实施。
DOI：
10.1118/1.2839098
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发表时间：
2008
期刊：
影响因子：
3.8
通讯作者：
Chetty,IndrinJ
中科院分区：
文献类型：
--
作者：
Fragoso,Margarida;Pillai,Sushakumari;Solberg,TimothyD;Chetty,IndrinJ
本研究描述了用于患者特定治疗计划的蒙特卡罗（MC）电子束剂量计算算法的α释放的建模、实验验证和临床实施。使用标准形状的电子施加器和100 cm的源-表面距离（SSD），对来自Siemens（Primus）直线加速器的6 - 18 MeV范围内的射束能量进行MC电子束建模。对于所有施用器尺寸，MC计算和测量之间的一致性平均在2 mm内。然而，对于模型化的最大施源器和所有能量，在离轴剂量曲线中观察到了数量级的差异。计算了不同SSD的施加器中插入的标准电子锥和方形切口的输出因子，并发现其在测量数据范围内。使用电离室和固体水平板中的薄膜以及含有骨和肺材料的拟人模型对MC电子束模型进行了实验验证。计算和测量的剂量分布之间的一致性在范围内。在高度不规则解剖结构（如耳朵、面部和乳房）中病变的4个患者治疗计划中进行了临床比较，其中在患者治疗中使用了定制设计的团注和射野成形块。出于比较目的，还使用常规笔形射束（PB）算法和治疗计划系统进行治疗计划。患者治疗计划的MC和PB剂量计算之间的差异很大，特别是在目标紧邻低密度组织（例如肺和气腔）的解剖结构中。关于监视器单元计算，对于两名接受倾斜射束治疗并涉及高度不规则表面的患者，MC和PB算法之间的最大差异在4.0%和5.0%之间，即，胸部和脸颊。报告了总体不确定度值（剂量体素平均值）的临床结果，范围为至，并使用边长为0.3 cm的立方体素进行计算。定时值范围为2 min至24.5 h，取决于用于定义上述总体不确定性值的患者解剖结构的计算机断层扫描切片的射野大小、射束能量、数量和厚度。
This study describes the modeling and the experimental verification and clinical implementation of the alpha release of Monte Carlo (MC) electron beam dose calculation algorithm for patient‐specific treatment planning. The MC electron beam modeling was performed for beam energies ranging from 6 to 18 MeV from a Siemens (Primus) linear accelerator using standard‐shaped electron applicators and 100 cm source‐to‐surface distance (SSD). The agreement between MC calculations and measurements was, on average, within and 2 mm for all applicator sizes. However, differences of the order of were noted in the off‐axis dose profiles for the largest applicator modeled and for all energies. Output factors were calculated for standard electron cones and square cutouts inserted in the applicator for different SSDs and were found to be within of measured data. Experimental verification of the MC electron beam model was carried out using an ionization chamber and film in solid‐water slab and anthropomorphic phantoms containing bone and lung materials. Agreement between calculated and measured dose distributions was within . Clinical comparison was performed in four patient treatment plans with lesions in highly irregular anatomies, such as the ear, face, and breast, where custom‐designed bolus and field shaping blocks were used in the patient treatments. For comparison purposes, treatment planning was also performed using the conventional pencil beam (PB) algorithm with the treatment planning system. Differences between MC and PB dose calculations for the patient treatment plans were significant, particularly in anatomies where the target was in close proximity to low density tissues, such as lung and air cavities. Concerning monitor unit calculations, the largest differences obtained between MC and PB algorithms were between 4.0% and 5.0% for two patients treated with oblique beams and involving highly irregular surfaces, i.e., breast and cheek. Clinical results are reported for overall uncertainty values (averaged over voxels with doses ) ranging from to and calculations were performed using cubic voxels with side 0.3 cm. Timing values ranged from 2 min to 24.5 h, depending on the field size, beam energy, number, and thickness of computed tomography slices used to define the patient's anatomy for the overall uncertainty values mentioned above.