GEANT4 for breast dosimetry: parameters optimization study
GEANT4 for breast dosimetry: parameters optimization study
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DOI：
10.1088/0031-9155/60/16/n311
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发表时间：
2015-08-21
影响因子：
3.5
通讯作者：
Longo, R.
中科院分区：
文献类型：
--
作者：
Fedon, C.;Longo, F.;Longo, R.
乳腺平均剂量（MGD）是乳腺摄影的主要剂量学指标。通过将入射皮肤空气比释动能（ESAK）乘以归一化腺体剂量（DgN）系数获得MGD评价。虽然ESAK是一个经验量，但DgN系数只能用蒙特卡罗（MC）方法估计。因此，需要一个MC参数基准，以有效地评估DgN系数。GEANT 4是一个MC工具包，适用于医疗目的，为用户提供了几个计算选择。在这项工作中，我们调查的GEANT 4性能测试的主要PhysicsLists的医疗应用。四个电磁PhysicsLists实现：线性衰减系数计算乳腺腺体0%，50%，100%的能量范围8-50 keV和DgN系数进行了评估。结果与已发表的数据进行了比较。拟合方程估计的G-因子参数，介绍了文献中的非均匀介质中传递的剂量，在腺体组织中，提出了这个参数的相互作用或回顾性的应用进行了讨论。G4 EmLivermorePhysicsList显示了线性衰减系数与理论值和已发表数据的最佳一致性。此外，良好的相关系数（r（2）>0.99）的DgN系数与literation.The最终目标的研究是确定，为第一次，一个基准的参数，可能是有用的，为未来的乳腺剂量学研究与GEANT 4。
Mean glandular dose (MGD) is the main dosimetric quantity in mammography. MGD evaluation is obtained by multiplying the entrance skin air kerma (ESAK) by normalized glandular dose (DgN) coefficients. While ESAK is an empirical quantity, DgN coefficients can only be estimated with Monte Carlo (MC) methods. Thus, a MC parameters benchmark is needed for effectively evaluating DgN coefficients. GEANT4 is a MC toolkit suitable for medical purposes that offers to the users several computational choices. In this work we investigate the GEANT4 performances testing the main PhysicsLists for medical applications. Four electromagnetic PhysicsLists were implemented: the linear attenuation coefficients were calculated for breast glandularity 0%, 50%, 100% in the energetic range 8-50 keV and DgN coefficients were evaluated. The results were compared with published data. Fit equations for the estimation of the G-factor parameter, introduced by the literature for converting the dose delivered in the heterogeneous medium to that in the glandular tissue, are proposed and the application of this parameter interaction-by-interaction or retrospectively is discussed. G4EmLivermorePhysicsList shows the best agreement for the linear attenuation coefficients both with theoretical values and published data. Moreover, excellent correlation factor (r(2)>0.99) is found for the DgN coefficients with the literature.The final goal of this study is to identify, for the first time, a benchmark of parameters that could be useful for future breast dosimetry studies with GEANT4.