Valicenti R K, Kirov A S, Meigooni A S, Mishra V, Das R K, Williamson J F
Radiation Oncology Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Med Phys. 1995 Jun;22(6):821-9. doi: 10.1118/1.597484.
Despite widespread use of high-intensity Ir-192 remotely afterloaded sources, no published measured or calculated dose-rate tables for currently used source designs are available. For a pulsed dose-rate Ir-192 source, both transverse axis (0.5-10 cm) and two-dimensional polar dose-rate profiles (1.5, 3, and 5 cm) were measured with thermoluminescent dosimetry in a solid water phantom. Dose rates were normalized to measured air-kerma strength, and the source geometry was verified by pinhole autoradiography and transmission radiography. At each measurement point, dose rates were calculated by a Monte Carlo photon transport (MCPT) code, which realistically modeled the experimental phantom, source, and detector geometry. Agreement between MCPT absolute dose-rate calculations and measurements averaged 3% and was less than 5%, demonstrating that Monte Carlo simulation is an accurate and powerful tool for two-dimensional dosimetric characterization of high activity Ir-192 sources.
尽管高强度铱 - 192后装源已被广泛使用，但目前尚无已发表的关于当前使用的源设计的测量或计算剂量率表。对于脉冲剂量率铱 - 192源，在固体水模体中使用热释光剂量测定法测量了横轴（0.5 - 10厘米）和二维极坐标剂量率分布（1.5、3和5厘米）。剂量率通过测量的空气比释动能强度进行归一化，并且通过针孔放射自显影和透射射线照相法验证了源的几何形状。在每个测量点，剂量率由蒙特卡罗光子传输（MCPT）代码计算得出，该代码真实地模拟了实验模体、源和探测器的几何形状。MCPT绝对剂量率计算值与测量值之间的一致性平均为3%，且小于5%，这表明蒙特卡罗模拟是用于高活度铱 - 192源二维剂量学表征的准确且强大的工具。
