el-Khatib E E, Podgorsak E B, Pla C
Med Phys. 1987 Jan-Feb;14(1):135-9. doi: 10.1118/1.596100.
Attenuation properties of Lipowitz's metal have been studied for narrow and broad beams of cobalt-60 gamma rays and 4-10 MV x-rays. The measured transmitted fraction for geometries used in radiotherapy depends on the field size and depth of measurement. Therefore a calculation of dose for partially attenuated beams based on narrow beam attenuation coefficients can cause large errors in dosimetry. Our simple calculation of transmitted fractions based on primary attenuation and scattered radiation agrees quite well with the measured data for therapeutic geometries. Also given is a table for linear, mass attenuation, and mass energy absorption coefficients of Lipowitz's metal in the photon energy range from 10 keV to 10 MeV.
已针对钴 - 60γ射线窄束和宽束以及4 - 10兆伏X射线研究了利波维茨合金的衰减特性。放射治疗中使用的几何形状的测量透射分数取决于射野大小和测量深度。因此，基于窄束衰减系数计算部分衰减束的剂量会在剂量测定中导致较大误差。我们基于一次衰减和散射辐射对透射分数的简单计算与治疗几何形状的测量数据相当吻合。还给出了利波维茨合金在10千电子伏至10兆电子伏光子能量范围内的线性、质量衰减和质量能量吸收系数表。
