利用Barracuda系统测量医用CT剂量指数量值不确定度评定

Evaluation of uncertainty in measurement of computed tomography dose index by Barracuda system

目的为保证医用CT剂量指数量值的准确性,评定其不确定度。方法建立Barracuda系统10 cm长杆电离室测量CT剂量指数数学模型,分析不确定度来源,通过计算给出不确定度。结果相对扩展不确定度为6.5%。结论利用Bar-racuda系统测量医用CT剂量指数量值不确定度主要受测量系统不确定度、校准因子、层厚偏差等分量的影响。

[Objective]In order to ensure the accuracy of computed tomography dose index,to evaluate the measurement uncertainty.[Methods]The mathematical model of Barracuda system with 10 cm long ionization chamber in measurement of computed tomography dose index was established,the uncertainty was calculated by analyzing the uncertainty source.[Results]The relative expanded uncertainty was 6.5%.[Conclusion]The uncertainty of Barracuda system in measurement of computed tomography dose index is mainly influenced by the uncertainty of the measurement system,the calibration factors and the thickness deviation.