Janicki C, Duggan D M, Rahdert D A
Centre Hospitalier de l'Université de Montréal, Dept. de médecine nucléaire, Québec, Canada.
Med Phys. 2001 Jul;28(7):1397-405. doi: 10.1118/1.1380214.
A computer dose model for a low energy gamma-emitting stent in a heterogeneous medium is described. The method is based on the Sievert model which is adapted to the dose-point-kernel (DPK) model to compute the dose distribution about filtered gamma sources (Sievert-DPK model). The new gamma stent model can take into account effects such as the metallic wire attenuation and the presence of dense calcified plaque in a stented artery. The Sievert-DPK model is tested against numerical simulations around cylindrical shell sources with dimensions comparable to those of a stent using a Monte Carlo transport code. For low energy gamma sources (Cs-131 and Pd-103), it is shown that the Sievert-DPK model is consistent with the Monte Carlo results to about 5%-10% for distances up to 5 mm from the cylindrical surface and 2.5 mm beyond the cylinder edges. These results indicate that the Sievert-DPK model may be useful to predict the dose in intravascular therapy applications for heterogeneous systems consisting of soft tissue, metal and dense plaque.
描述了一种用于非均匀介质中低能γ发射支架的计算机剂量模型。该方法基于西弗特模型，该模型适用于剂量点核（DPK）模型，以计算关于滤波γ源的剂量分布（西弗特-DPK模型）。新的γ支架模型可以考虑诸如金属丝衰减和支架置入动脉中致密钙化斑块的存在等影响。使用蒙特卡罗输运代码，针对尺寸与支架相当的圆柱壳源周围的数值模拟对西弗特-DPK模型进行了测试。对于低能γ源（Cs-131和Pd-103），结果表明，对于距离圆柱表面5 mm以内和圆柱边缘以外2.5 mm的距离，西弗特-DPK模型与蒙特卡罗结果的一致性约为5%-10%。这些结果表明，西弗特-DPK模型可能有助于预测由软组织、金属和致密斑块组成的非均匀系统在血管内治疗应用中的剂量。
