Wallace R E, Fan J J
Department of Radiation Oncology, University of California, Los Angeles 90095-6951, USA.
Med Phys. 1998 Nov;25(11):2190-6. doi: 10.1118/1.598416.
Dosimetric measurements were performed to characterize a new 125I source that is similar in design to existing sources and that has application in interstitial brachytherapy. Thermoluminescent dosimeters were placed in phantom to measure transverse-axis and angular dose profiles over a range of distances from 0.5 to 7 cm. The data were analyzed in terms of parameters recommended by AAPM Task Group #43. Tabular data evaluated in liquid water are provided for the dose-rate constant, lambda, radial dose function, g(r), the anisotropy function, F(r, theta), the anisotropy factor, phi an(r), the point-source approximation anisotropy constant, phi an, and the point-source average dose rate times the square of distance for unit air kerma strength, r2D(r). The new source is compared to the model 6702 125I source design, demonstrating similar dose-rate constant, lambda, and radial dose function, g(r). Differences in the anisotropy of the dose distributions are discussed. Finally, a comparison of the radial dose distribution is made between liquid water and tissue equivalent materials.
进行剂量测定以表征一种新型125I源，其设计与现有源相似，可应用于间质近距离放射治疗。将热释光剂量计置于体模中，以测量在0.5至7 cm范围内不同距离处的横轴和角剂量分布。根据美国医学物理学家协会任务组#43推荐的参数对数据进行分析。给出了在液态水中评估的表格数据，包括剂量率常数λ、径向剂量函数g(r)、各向异性函数F(r,θ)、各向异性因子φan(r)、点源近似各向异性常数φan以及单位空气比释动能强度下点源平均剂量率乘以距离的平方r2D(r)。将新源与6702型125I源设计进行比较，结果表明二者的剂量率常数λ和径向剂量函数g(r)相似。讨论了剂量分布各向异性的差异。最后，对液态水和组织等效材料之间的径向剂量分布进行了比较。
