Impact of source-production revision on the dose-rate constant of 131Cs interstitial brachytherapy sources.
Impact of source-production revision on the dose-rate constant of 131Cs interstitial brachytherapy sources.
复制标题
源生产修订对 131Cs 间质近距离放射治疗源剂量率常数的影响。
DOI：
10.1118/1.3453766
复制
发表时间：
2010
期刊：
影响因子：
3.8
通讯作者：
Nath,Ravinder
中科院分区：
文献类型：
--
作者：
Chen,Zhe;Bongiorni,Paul;Nath,Ravinder
目的自2004年推出以来，CS-1 Rev.1型放射源已在许多放射治疗诊所用于前列腺近距离放射治疗。2006年，该源代码模型进行了Rev.2生产修订。这项工作的目的是调查的剂量影响的修订版。2生产修订使用高分辨率photon spectrometry.MethodsThree CS-1修订版。1和3 CS-1修订版。2源在这项研究中使用。使用为低能光子光谱法设计的高分辨率锗探测器测量每个源在源的横平分线上发射的相对光子能谱。根据测量的光子能谱和源中的放射性分布，确定每个源的剂量率常数。Rev.2生产修订的影响进行了量化，通过比较所发射的光子能量谱和确定的值之前和之后的生产revision.ResultsThe相对光子能量谱的主要排放量的来源被发现是几乎相同的之前和之后的Rev.2修订。然而，从铌中产生的荧光X射线的光谱部分，在源结构材料中存在的微量元素，被发现之间的Rev.1和Rev.2源显着不同。从Rev.2源的和荧光X射线的峰值强度约为从Rev.1源的35%。因此，Rev.2源的标称值被发现是大于为Rev.1源确定的approximates.ConclusionsA显着减少（65%）相对铌荧光X射线产率中观察到的Rev.2源。发现这种降低对剂量率常数的影响很小，相对差异小于1%。本研究表明，光子光谱法可用作监测和量化近距离放射治疗源生产修订的剂量学效应的灵敏和方便的工具。由于生产修订可能会改变近距离放射治疗源的几何形状和原子组成，因此应仔细监测和评估每次生产修订的剂量学影响。
PurposeSince its introduction in 2004, the model CS‐1 Rev.1 source has been used in many radiation therapy clinics for prostate brachytherapy. In 2006, this source model underwent a Rev.2 production revision. The aim of this work was to investigate the dosimetric influences of the Rev.2 production revision using high‐resolution photon spectrometry.MethodsThree CS‐1 Rev.1 and three CS‐1 Rev.2 sources were used in this study. The relative photon energy spectrum emitted by each source in the transverse bisector of the source was measured using a high‐resolution germanium detector designed for low‐energy photon spectrometry. Based on the measured photon energy spectrum and the radioactivity distribution in the source, the dose‐rate constant of each source was determined. The effects of the Rev.2 production revision were quantified by comparing the emitted photon energy spectra and the values determined for the sources manufactured before and after the production revision.ResultsThe relative photon energy spectrum originating from the principal emissions of was found to be nearly identical before and after the Rev.2 revision. However, the portion of the spectrum originating from the production of fluorescent x rays in niobium, a trace element present in the source construction materials, was found to differ significantly between the Rev.1 and Rev.2 sources. The peak intensity of the and fluorescent x rays from the Rev.2 source was approximately 35% of that from the Rev.1 source. Consequently, the nominal value of the Rev.2 source was found to be greater than that determined for the Rev.1 source by approximately .ConclusionsA significant reduction (65%) in relative niobium fluorescent x‐ray yield was observed in the Rev.2 sources. The impact of this reduction on the dose‐rate constant was found to be small, with a relative difference of less than 1%. This study demonstrates that photon spectrometry can be used as a sensitive and convenient tool for monitoring and for quantifying the dosimetric effects of brachytherapy source‐production revisions. Because production revision can change both the geometry and the atomic composition of brachytherapy sources, its dosimetric impact should be carefully monitored and evaluated for each production revision.