Pre-treatment radiotherapy dose verification using Monte Carlo doselet modulation in a spherical phantom
Pre-treatment radiotherapy dose verification using Monte Carlo doselet modulation in a spherical phantom
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在球形模型中使用蒙特卡罗剂量调制验证治疗前放射治疗剂量
DOI：
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发表时间：
2013
影响因子：
3.5
通讯作者：
S. Zavgorodni
中科院分区：
文献类型：
--
作者：
R. Townson;S. Zavgorodni
由于放射治疗的复杂性日益增加，精确的剂量验证已成为临床治疗过程中必不可少的一部分。这项工作的目的是开发一种治疗前验证技术，能够快速重建3D剂量分布从共面和非共面治疗。对于每个治疗射野，在非透射模式下拍摄电子射野图像（射束中无患者），从而可以导出输送的注量图。然后在球形水模中进行剂量重建，通过调制和求和Monte Carlo（MC）剂量集，定义在球形坐标系上，并根据钳口上方的方位角对称注量预先计算。该技术，被称为球形剂量波调制（SDM）方法，基本上消除了MC剂量计算的统计不确定性，通过利用患者独立的相空间和虚拟球形水模中的方位角对称性。例如，这种对称性允许剂量重建所需的剂量组数量减少到1/250。在这项工作中，仅使用了51个径向分箱的剂量组（每个剂量组由相空间的给定环中的所有粒子生成，方位角地重新分布到小的圆柱形扇区中）。SDM方法减轻了这种类型的剂量重建的计算最密集的部分--阅读、加权和求和剂量矩阵。该系统的准确性进行了测试，对MC计算以及我们以前报道的相空间调制方法，使用一系列的开放领域和调强放射治疗的情况下。与完全MC模拟相比，SDM方法的平均卡方检验和伽马检验3%/3 mm成功率分别为98.6%和99.5%。在单个处理器内核上，每个治疗野的总计算时间为96 s。
Due to the increasing complexity of radiotherapy delivery, accurate dose verification has become an essential part of the clinical treatment process. The purpose of this work was to develop a pre-treatment verification technique capable of quickly reconstructing 3D dose distributions from both coplanar and non-coplanar treatments. For each treatment field, electronic portal images were taken in non-transmission mode (with no patient in the beam) allowing the derivation of the delivered fluence maps. The dose reconstruction was then performed in a spherical water phantom by modulating and summing the Monte Carlo (MC) doselets, defined on a spherical co-ordinate system, and pre-calculated from azimuthally symmetric fluence above the jaws. The technique, called the spherical doselet modulation (SDM) method, essentially eliminates the statistical uncertainty of the MC dose calculations by exploiting the azimuthal symmetry in both a patient-independent phase-space and in a virtual spherical water phantom. For example, this symmetry allowed the number of doselets necessary for dose reconstruction to be reduced by a factor of ∼250. In this work, only 51 radially binned doselets were used (each generated from all particles in a given annulus of the phase-space, azimuthally redistributed into a small cylindrical sector). The SDM method mitigates the most computationally intensive part of this type of dose reconstruction-–reading, weighting and summing dose matrices. The accuracy of the system was tested against MC calculations as well as our previously reported phase-space modulation method, using a series of open field and IMRT cases. The mean chi- and gamma-test 3%/3 mm success rates of the SDM method were 98.6% and 99.5%, respectively, when compared to full MC simulation. The total calculation time was 96 s per treatment field on a single processor core.
DOI：
10.1016/s0360-3016(01)01502-4
发表时间：
2001-06-01
影响因子：
7
作者：
Pugachev, A;Li, JG;Xing, L
通讯作者：
Xing, L