模拟人体反散射材料试验研究

Experimental Study on the Backscatter Properties of Various Phantoms Used in Medical X-ray Diagnostic Dosimetry and QA.

目的 确定在医用诊断X射线剂量学中常用模体的反散射特性与人体反散射特性的近似程度。方法 在相同投照条件下 ,对 8种常用模拟散射体和真人的反散射因子进行测定以及比较分析。结果 在低能区 ,2cm厚有机玻璃板的反散射特性 ,以及在高能区水模体的反散射特性更接近人体。在常规胸腹部检查时 ,反散射线的剂量约为主射线剂量的 40 %。结论 用于质量控制的标准化模体只是一种约定的模体 ,其目的是便于国际上的协调一致和监测数据的比较 ,并非反映患者实受剂量。

Objective To determine the approximation of backscatter property of human body by stimulation phantoms commonly used in medical diagnostic X-ray dosimetry.Methods To measure and compare the backscatter factors of various kinds of phantom and human body under the identical projection conditions.Results In the lower energy region,the backscatter property of PMMA is close to that of human body,and in the higher energy region the backscatter property of water is close to that of human body.For the general X ray examinations on chest and abdomen.The dose due to the backscatter rays is about 40% of the dose of the primary rays.Conclusion A standardized phantom used in QC in radiography is a commitment phantom,for which the purpose is to harmonize the method and to make easy to compare the measurement data.