复合型种子源^(125)I-^(103)Pd剂量场分布的蒙特卡罗模拟与实验测定

在相同参数条件下,使用MCNP5、EGSnrc两种蒙特卡罗方法模拟和实验测定^(125)Ⅰ-^(103)Pd复合种子源剂量场分布情况,实验中采用LiF热释光剂量片(GR-200)记录吸收剂量,有机玻璃为组织等效材料。通过与实验结果比较,两种程序在模拟粒子输运方法、几何描述、材料截面数据等方面结果不同,但是两种程序计算结果与实验符合较好。结果表明,MCNP5和EGSnrc可准确计算种子源剂量场分布。EGSnrc得到的剂量数据更加准确。

Determination of dosimetric characteristics for ^(125)I seed source with FLUKA code

This work determined a new Monte Carlo code(FLUKA) that can be used to calculate the dosimetric characteristics of seed sources. Dosimetric parameters(dose rate constant, radial dose function, and anisotropy function) of model 6711125 I seed source were calculated with FLUKA. The results were compared to the relative data recommended by AAPM TG43U1: dose rate constant with FLUKA was in agreement with 2.041%;radial dose functions with FLUKA for distances ranging from 0.5 cm to 10 cm, the deviation was less than 5%.Therefore the FLUKA code can be used to calculate the dosimetric characteristics of seed sources.

点核积分计算6711型^(125)I籽粒源剂量参数

使用点核积分方法计算6711型^(125)I籽粒源参数,根据美国医学物理学家协会(American Association of Physicists in Medicine,AAPM)TG-43U1号报告推荐的剂量参数计算公式,可以获得6711型^(125)I籽粒源各参数。与AAPM TG-43U1推荐值比较,剂量常数相差6.76%,径向剂量函数值(不包括0.1 cm、0.15 cm、0.25 cm)最大相差2.27%,最小相差0.02%;与MCNP5(A General N-Particle Transport Code,Version 5)方法计算结果比较,剂量常数相差6.19%,径向剂量函数值(不包括0.1 cm、0.15 cm、0.25 cm)最大相差6.65%,最小相差0.06%。结果与推荐值符合较好,证明点核积分能够应用于籽粒源剂量参数计算。

MCNP5与EGSnrc比较计算125I种子源剂量参数

根据AAPM TG43U1的推荐,使用MCNP5与EGSnrc两种蒙特卡罗程序计算6711型125I种子源剂量计算参数,并将两者计算结果和AAPM推荐值比较,得到相对偏差结果如下:剂量率常数,MCNP5为0.62%,EGSnrc为2.07%;径向剂量函数,MNCP5为0.15%-5.12%,EGSnrc为0%-2.18%。两者计算结果均与推荐值符合得很好,而EGSnrc的计算结果更具优势。