Toroi P, Kosunen A
STUK-Radiation and Nuclear Safety Authority, PO Box 14, FIN-00881, Helsinki, Finland.
Phys Med Biol. 2009 May 7;54(9):N151-6. doi: 10.1088/0031-9155/54/9/N02. Epub 2009 Apr 8.
Kerma-area product (KAP) meters used for patient exposure monitoring in diagnostic x-ray imaging can be calibrated in situ with a reference KAP meter. The drawback of this tandem calibration method is the large energy dependence of the response of the reference KAP meter when typical KAP ionization chambers are used for this purpose. The energy dependence of a novel, large-area KAP meter (patient dose calibrator, PDC, Radcal) was therefore experimentally investigated. Its response was examined by measuring the calibration coefficients for standard calibration radiation qualities and several radiation qualities in the range generally used in diagnostic x-ray imaging. The PDC type of KAP meter has a smaller energy dependence than conventional KAP meters, and the half-value layer can be used as a radiation quality specifier for PDC-type chambers with an uncertainty of less than 2%. The accuracy of the tandem calibration method can be improved by using this type of KAP meter as a reference meter.
用于诊断X射线成像中患者照射量监测的比释动能面积乘积（KAP）仪可使用参考KAP仪进行现场校准。当使用典型的KAP电离室进行此操作时，这种串联校准方法的缺点是参考KAP仪响应的能量依赖性很大。因此，对一种新型大面积KAP仪（患者剂量校准仪，PDC，Radcal）的能量依赖性进行了实验研究。通过测量标准校准辐射质以及诊断X射线成像中常用范围内的几种辐射质的校准系数，来检验其响应。PDC型KAP仪的能量依赖性比传统KAP仪小，并且半值层可用作PDC型电离室的辐射质指定参数，不确定度小于2%。使用这种类型的KAP仪作为参考仪可提高串联校准方法的准确性。
