Monte Carlo dose calculations in homogeneous media and at interfaces: a comparison between GEPTS, EGSnrc, MCNP, and measurements.
Monte Carlo dose calculations in homogeneous media and at interfaces: a comparison between GEPTS, EGSnrc, MCNP, and measurements.
复制标题
均匀介质和界面处的蒙特卡罗剂量计算：GEPTS、EGSnrc、MCNP 和测量之间的比较。
DOI：
10.1118/1.1473134
复制
发表时间：
2002
期刊：
影响因子：
3.8
通讯作者：
Li,XAllen
中科院分区：
文献类型：
--
作者：
Chibani,Omar;Li,XAllen
三种蒙特卡罗光子/电子传输代码（GEPTS， EGSnrc和MCNP）在均匀介质（低介质和高介质）以及界面处的剂量测量中进行基准测试。简要概述了每个代码用于光子和电子（正电子）输运的物理模型。将0.5 MeV和1 MeV电子束入射均匀介质和多层介质的绝对量热剂量测量结果与三种程序的预测结果进行了比较。与暴露于伽玛源的两层介质中的剂量测量值进行了比较。此外，还比较了(a) 0.05至10 MeV的电子束和铅中的正电子点源，(b)高能光子（10和20 MeV）照射多层模体（水/钢/空气），以及(c)近距离治疗源的模拟（包括EGS4代码）。在均匀介质和多层介质中，GEPTS和EGSnrc的热电子剂量测量结果与预测结果吻合良好。发现MCNP输出依赖于能量索引方法（默认/ITS风格）。这种依赖关系在均质介质和界面处都很重要。除Be的情况外，与实验数据更为吻合。在低能量（0.05和0.1 MeV）下，与GEPTS和EGSnrc相比，铅中的剂量分布显示出更高的最大值。EGS4在高介质中产生过穿透性的电子剂量分布，特别是在低能量（<0.1 MeV）下。对于正电子，在铅中观察到GEPTS和EGSnrc之间的差异，因为在弹性多重散射和轫致辐射模型中，GEPTS将正电子与电子区分开来。对于源，在实验不确定度方面，计算和测量之间有很好的一致性。对于其他情况（10和20 MeV光子源和β源），三种代码之间存在很好的一致性。综上所述，在几乎所有的介质和能量研究中，GEPTS和EGSnrc结果之间的差异很小。MCNP结果在很大程度上取决于电子能量标引方法。
Three Monte Carlo photon/electron transport codes (GEPTS, EGSnrc, and MCNP) are benchmarked against dose measurements in homogeneous (both low‐ and high‐ media as well as at interfaces. A brief overview on physical models used by each code for photon and electron (positron) transport is given. Absolute calorimetric dose measurements for 0.5 and 1 MeV electron beams incident on homogeneous and multilayer media are compared with the predictions of the three codes. Comparison with dose measurements in two‐layer media exposed to a gamma source is also performed. In addition, comparisons between the codes (including the EGS4 code) are done for (a) 0.05 to 10 MeV electron beams and positron point sources in lead, (b) high‐energy photons (10 and 20 MeV) irradiating a multilayer phantom (water/steel/air), and (c) simulation of a brachytherapy source. A good agreement is observed between the calorimetric electron dose measurements and predictions of GEPTS and EGSnrc in both homogeneous and multilayer media. MCNP outputs are found to be dependent on the energy‐indexing method (Default/ITS style). This dependence is significant in homogeneous media as well as at interfaces. fits more closely the experimental data than except for the case of Be. At low energy (0.05 and 0.1 MeV), dose distributions in lead show higher maximums in comparison with GEPTS and EGSnrc. EGS4 produces too penetrating electron‐dose distributions in high‐ media, especially at low energy (<0.1 MeV). For positrons, differences between GEPTS and EGSnrc are observed in lead because GEPTS distinguishes positrons from electrons for both elastic multiple scattering and bremsstrahlung emission models. For the source, a quite good agreement between calculations and measurements is observed with regards to the experimental uncertainty. For the other cases (10 and 20 MeV photon sources and the beta source), a good agreement is found between the three codes. In conclusion, differences between GEPTS and EGSnrc results are found to be very small for almost all media and energies studied. MCNP results depend significantly on the electron energy‐indexing method.