Abstract：Objective To investigate the effect of automatic tube current modulation (ATCM) on abdominal CT image quality and radiation dose.Methods One hundred and eighty servicemen were randomly selected and divided into two groups for abdominal CT scan. The 40 people in the control group were scanned with the fixed tube current of 400mA while the 140 subjects in the experimental group were scanned by ATCM. The radiation dose indexes of each scanning scheme were recorded respectively, including the volumetric CT dose index (CTDIvol), dose length product (DLP), size-specific dose estimates (SSDE), and effective dose (ED). In addition, the CT values of the appendix, psoas major and subcutaneous fat in the images of each group were measured, and the Objective evaluation index of image quality was calculated. At the same time, two physicians who had been engaged in imaging diagnosis for more than 15 years made subjective evaluation of the two groups of images and recorded their scores. Univariate analysis of variance was used to compare the radiation doses and image quality between the two groups. The correlation between NI values and CTDIvol,DLP was analyzed via Pearson correlation analysis. Kappa test was used to analyze the consistency of CT image quality scores of the two imaging physicians in each group.Results The test values F of CTDIvolm, DLPm, SSDEm and EDm in the two groups were 3.14, 8.75, 1.82, 7.34, respectively (P<0.05), showing statistically significant difference. Compared with the control group, the experimental group had a significant reduction in the radiation dose. The image quality decreased to some extent. The statistical test values F of SD, SNRA and SNRPM in the two groups were 1.22, 2.93 and 5.38, respectively (P<0.05). The data difference between the two groups was statistically significant. The comparison test value of image scores between the two groups was F=1.34, P=0.176, with no statistically significant difference. There was a significant negative correlation between NI and CTDIvol DLP (r=-0.919,P<0.05). The consistency analysis of CT image scores by the two imaging physicians showed a strong consistency (Kappa=0.675).Conclusions ATCM used for abdominal CT examination can greatly reduce the radiation dose while ensuring the accuracy of diagnosis. It is highly applicable.
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2020, Vol. 31 
