多排螺旋CT辐射剂量表征量校正方法初探

摘要

目的：探讨多排螺旋CT检查所致辐射剂量的准确值与常用的CT辐射剂量表征量以及扫描参数之间的关系，以校正目前常用的CT辐射剂量表征量。方法：使用长杆电离室测量Siemens SOMATOM Definition Flash CT不同准值宽度、螺距以及管电压下直径16cm体模内剂量分布曲线，并使用SPSS软件进行分析。结果：测量得到的CTDIw和加权CTDI∞在0.05水平上有显著性差异，经校正后所得的加权CTDI∞与测量所得加权CTDI∞在0.05水平上无显著性差异。结论：多排螺旋CT目前常用的CT辐射剂量表征量缺乏准确性。经验证，根据实验结果得到的校正方法基本准确，可以对西门子Definition Flash CT的CTDIw进行校正，使用其他多排螺旋CT扫描其他部位时CTDIw的校正有待进一步研究。%Objective:To correct the characterizations of MDCT radiation dose by exploring the relationship between CTDIw,∞ and CTDIw.Methods: CTDI100 and CTDI∞ were measured under the conditions of different collimations, pitches and tube voltages of Siemens Definition Flash CT, and CTDIw and CTDIw,∞ were calculated.Results: There were significant differences between CTDIw and CTDIw,∞ which were measured at 0.05 level. And there were no significant differences between CTDIw,∞ after corrected and CTDIw,∞ which were measured at 0.05 level.Conclusion:The characterizations of MDCT which were commonly used were not accurate enough. The result after correction were very closed to the real CTDIw,∞. This showed that the method to correct CTDIw of Siemens Definition Flash CT was mostly accurate. And methods to correct CTDIw of other MDCT needed to be further studied.