Radiotherapy dose calculations in the presence of hip prostheses.
Radiotherapy dose calculations in the presence of hip prostheses.
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DOI：
10.1016/s0958-3947(02)00245-5
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发表时间：
2003-01-01
期刊：
影响因子：
--
通讯作者：
Mohan, Radhe
中科院分区：
文献类型：
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作者：
Keall, Paul J;Siebers, Jeffrey V;Mohan, Radhe
骨盆放射治疗患者髋关节假体的高密度和原子序数对我们精确计算剂量的能力提出了挑战。一种新的临床剂量计算算法，蒙特卡罗，将允许精确计算髋关节假体内外的辐射传输。本研究的目的是研究不同剂量计算算法对幻体和患者几何形状产生准确治疗计划的能力。使用蒙特卡罗、叠加、铅笔束和非异质性校正算法计算高原子序数假体和患者几何形状中的剂量分布。用深度剂量曲线和剂量剖面曲线分析幻象剂量分布。通过等剂量曲线、剂量-体积直方图（DVHs）和肿瘤控制概率/正常组织并发症概率（TCP/NTCP）计算分析患者剂量分布。蒙特卡罗计算分别预测了近端和远端假体界面的剂量增强和减少，而叠加和铅笔束计算则没有。然而，远离假体，剂量计算算法之间的差异减小。用叠加法计算的治疗方案显示出与蒙特卡罗计划相似的等剂量曲线、dvh和TCP/NTCP，但在膀胱中，蒙特卡罗预测的剂量略低。用铅笔束法计算的治疗方案或未进行异质性校正的治疗方案与蒙特卡罗方案有显著差异。
The high density and atomic number of hip prostheses for patients undergoing pelvic radiotherapy challenge our ability to accurately calculate dose. A new clinical dose calculation algorithm, Monte Carlo, will allow accurate calculation of the radiation transport both within and beyond hip prostheses. The aim of this research was to investigate, for both phantom and patient geometries, the capability of various dose calculation algorithms to yield accurate treatment plans. Dose distributions in phantom and patient geometries with high atomic number prostheses were calculated using Monte Carlo, superposition, pencil beam, and no-heterogeneity correction algorithms. The phantom dose distributions were analyzed by depth dose and dose profile curves. The patient dose distributions were analyzed by isodose curves, dose-volume histograms (DVHs) and tumor control probability/normal tissue complication probability (TCP/NTCP) calculations. Monte Carlo calculations predicted the dose enhancement and reduction at the proximal and distal prosthesis interfaces respectively, whereas superposition and pencil beam calculations did not. However, further from the prosthesis, the differences between the dose calculation algorithms diminished. Treatment plans calculated with superposition showed similar isodose curves, DVHs, and TCP/NTCP as the Monte Carlo plans, except in the bladder, where Monte Carlo predicted a slightly lower dose. Treatment plans calculated with either the pencil beam method or with no heterogeneity correction differed significantly from the Monte Carlo plans.