Ling C C, Gromadzki Z C, Rustgi S N, Cundiff J H
Radiology. 1983 Mar;146(3):791-2. doi: 10.1148/radiology.146.3.6828694.
Radiation fluence distribution around 192Ir and 198Au seeds of the type used for brachytherapy application was measured using a NaI crystal connected to a multi-channel analyzer. The radiation fluence, determined as a function of the angle between the seed axis and the direction of detection, is anisotropic with the fluence along the seed axis amounting to 78% of that perpendicular to the seed axis for seeds of both isotopes. The region of fluence reduction is broader for 198Au seeds, extending from 0-45 degrees; for 192Ir the decrease in fluence is evident for angles of 0-20 degrees. Integration of the angular distribution over 4 pi geometry indicated the effective activity of the implants to be 4% and 1% less than the nominal activity for the 198Au and 192Ir seeds, respectively, based on calibration measurements perpendicular to the seed axis.
使用连接到多通道分析仪的碘化钠晶体，测量了用于近距离放射治疗的192铱和198金种子周围的辐射注量分布。辐射注量是根据种子轴与检测方向之间的角度的函数确定的，对于两种同位素的种子，其辐射注量是各向异性的，沿种子轴的注量相当于垂直于种子轴的注量的78%。198金种子的注量降低区域更宽，从0 - 45度延伸；对于192铱，在0 - 20度的角度下注量降低明显。基于垂直于种子轴的校准测量，在4π几何形状上对角度分布进行积分表明，198金和192铱种子植入物的有效活度分别比标称活度低4%和1%。
