乳腺X射线摄影剂量仪校准装置的几个影响量的测试

Measurement of some influence quantities of the calibration apparatus for mammograhy dosimeters

目的对乳腺X射线摄影剂量仪校准装置的几个影响量的测试。方法在标准辐射质下,使用二级标准剂量学实验室(SSDL)的参考级剂量仪器对辐射场的均匀性、散射辐射线的影响,以及装置的长期稳定性等特性进行测定。结果该标准辐射质中辐射场的均匀性(Ф60mm)为±0·98%;在测点上散射份额贡献小于0·12%以及装置的长期稳定性(5个月内)不大于1·8%(±1s)。结论该装置辐射场的均匀性、散射辐射贡献和装置的长期稳定性等几个影响量均满足SSDL标准的要求。

Objective To measure some influence quantities of the calibration apparatus for Mammography dosimeters. Methods Under the standard radiation quality conditions, the radiation field homogeneity, the scatter radiation contributions and long term stability of the reference instrument were measured using the reference-class ionization chamber at the SSDL. Results The field homogeneity （φ mm）is in ±0.98% ;the scatter radiation contributions at the poit of test were below 0.12% ,the long term stability of calibration apparatus was no more than 1.8 % （ ±1 s ） over 5 months. Conclusion As indicated above the some influence quantities may meet the requirements for the calibration apparatus at the SSDL.