Comparative Study of Volume Computed Tomography Dose Index and Size-Specific Dose Estimate Head in Computed Tomography Examination for Adult Patients Based on the Mode of Automatic Tube Current Modulation

Abstract

BACKGROUND The aim of this study was to compare the metrics of volume computed tomography index (CTDIvol) and size-specific dose estimate (SSDE), and quantity the differences in head CT examinations of adult patients. MATERIAL AND METHODS A total of 157 patients underwent head CT examination were enrolled in this retrospective study. Pearson correlation analysis and linear regression correlation analysis were performed to observe the correlation between the dose metrics of CTDIvol and SSDEaver versus tube current product (mAs) and water equivalent diameter (WED). Correlated factors of CTDIvol and SSDEaver were analyzed by multivariate linear stepwise regression analysis. RESULTS A sum of 4239 data settings were measured: slices with WED >16 cm was 71.05%, and the slices with f <1 was 72.64%. The average value of the absolute difference between WED and the diameter of AAPM head phantom was 2.24±1.42 cm. Statistically significant difference was found between the values of CTDIvol and SSDEaver (P=0.000). The dispersion degree of the CTDIvol values was greater than that of SSDEaver. Strong positive correlation was shown between CTDIvol and mAs (P=0.000), as well as CTDIvol and WED (P=0.000). Strong positive correlation was shown between SSDEaver and mAs (P=0.000), and moderate correlation for SSDEaver and WED (P=0.000). Both the metrics of mAs and WED were included in the multivariate linear stepwise regression equation to observe the effect of related factors on the value of SSDEaver. CONCLUSIONS SSDEaver with better representative can reproduce the radiation dosage of the specific adult patients in head CT examination.