UNASSIGNED:根据美国医学物理学家协会第43任务组的建议,蒙特卡洛(MC)研究人员应在探索代码的新特征时复制以前发表的剂量分布。本研究的目的是对使用EGSnrc代码系统的新MC用户代码egs_brachy为三种不同的放射性核素192Ir计算的TG-43剂量测定参数进行基准测试,169Yb,和125I代表高,中介-,和低能源,分别。
UNASSIGNED:本研究中研究的近距离放射治疗源是高剂量率(HDR)192IrVariSource(型号VS2000),169YbHDR(4140型),和125I-低剂量率(LDR)(OcuProsta模型)。TG-43剂量测定参数,如空气强度,Sk,剂量率常数,Λ,径向剂量函数,g(r)和各向异性函数,F(r,使用MC代码egs_brachy在质量密度为0.998g/cm3的圆柱形水模中计算θ)和二维(2D)吸收剂量率数据(远表)。192IrVS2000和169Yb光源的体模尺寸为80厘米直径×80厘米高,而对于125IOcuProsta来源,对于MC计算,考虑了30厘米直径×30厘米高度的圆柱形水模。
UNASSIGNED:将使用egs_brachy计算的剂量测定参数与文献中发布的值进行比较。本研究的剂量率常数的计算值与所有调查来源的统计不确定性范围内的公布值一致。在egs_brachy计算的径向剂量函数之间发现了良好的一致性,g(r),各向异性函数,和2D剂量率数据,以及相同体模尺寸的已发布值(在2%以内)。对于192IrVS2000源,在18cm处观察到约28%的g(r)值的差异,这是由于体模尺寸的差异。
UNASSIGNED:该研究验证了使用egs_brachy计算的192Ir的TG-43剂量参数,169Yb,和125I近距离放射治疗源与文献中公布的值。
UNASSIGNED: As per the recommendations of the American Association of Physicists in Medicine Task Group 43, Monte Carlo (MC) investigators should reproduce previously published dose distributions whenever new features of the code are explored. The purpose of the present study is to benchmark the TG-43 dosimetric parameters calculated using the new MC user-code
egs_brachy of EGSnrc code system for three different radionuclides 192Ir, 169Yb, and 125I which represent high-, intermediate-, and low-energy sources, respectively.
UNASSIGNED: Brachytherapy sources investigated in this study are high-dose rate (HDR) 192Ir VariSource (Model VS2000), 169Yb HDR (Model 4140), and 125I -low-dose-rate (LDR) (Model OcuProsta). The TG-43 dosimetric parameters such as air-kerma strength, S k, dose rate constant, Λ, radial dose function, g(r) and anisotropy function, F(r,θ) and two-dimensional (2D) absorbed dose rate data (along-away table) are calculated in a cylindrical water phantom of mass density 0.998 g/cm3 using the MC code
egs_brachy. Dimensions of phantom considered for 192Ir VS2000 and 169Yb sources are 80 cm diameter ×80 cm height, whereas for 125I OcuProsta source, 30 cm diameter ×30 cm height cylindrical water phantom is considered for MC calculations.
UNASSIGNED: The dosimetric parameters calculated using
egs_brachy are compared against the values published in the literature. The calculated values of dose rate constants from this study agree with the published values within statistical uncertainties for all investigated sources. Good agreement is found between the
egs_brachy calculated radial dose functions, g(r), anisotropy functions, and 2D dose rate data with the published values (within 2%) for the same phantom dimensions. For 192Ir VS2000 source, difference of about 28% is observed in g(r) value at 18 cm from the source which is due to differences in the phantom dimensions.
UNASSIGNED: The study validates TG-43 dose parameters calculated using
egs_brachy for 192Ir, 169Yb, and 125I brachytherapy sources with the values published in the literature.