医用CT剂量指数测量结果的不确定度评定

Uncertainty analyses of computed tomography dose index

为了使医用诊断计算机断层摄影装置(CT)X射线辐射源在模体中的剂量指数测量结果的不确定度评定合理,基于用带有100mm长杆电离室的积分剂量仪测量CT剂量指数的数学模型,对其测量不确定度来源进行分析,列出了方差、灵敏系数及标准不确定度的计算公式,从而给出了CT剂量指数测量的合成标准不确定度和扩展不确定度。

In order to make the uncertainty of the dose index measurement in the head phantom reasonable for the medical diagnostic X-ray radiation sourees of the computed tomography （CT）, the measurement uncertainty components were analyzed according to the mathematical model for the computed tomography dose index test method with a I00 mm ionization chamber. And the calculated formula for square-error, sensitivity coeflieient and standard deviation were listed in the article. As the results, the standard measurement uncertainty and its expanded uncertainty of CT dose index were presented.