History

Background: Multidetector computed tomography (MDCT) has become a routine imaging modality for numerous clinical applications due to its extensive availability, reduced invasiveness, rapid scanning time, great anatomical resolution, and superior diagnostic value. At the same time, the radiation dose to the patient and the concern surrounding this problem has also increased.Objective: The aim of this study is to assess image quality related to patient radiation dose for multidetector computed tomography in chest and brain CT examinations.Patients and Methods: A total of 60 patients who underwent chest and brain scans from four hospitals on 16, 32, and 64 slice (CT) scanners. Clinical image data were used for image quality calculation and dose assessment. The image quality is calculated by CNR & SNR. The CT dose volume index (CTDIv) and dose length product (DLP) were documented from the image display.Results: Regarding the radiographic parameters, the mean value of radiation doses (CTDIv, DLP and ED) to patients were higher from 64 slice scanner for the chest CT scan examination (12.6±0.21, 478.6±73.3 and 6.7±1.026) respectively. It was significantly lower in 32 and 16 slice multi detector CT (9.34±0.23, 341.86±11.56 and 4.78±0.164) (7.6±1.5, 247.9±52.6 and 3.46±0.738) respectively. the same parameters in brain CT scan examinations, the mean value of radiation doses (CTDIv, DLP and ED) to patients were higher from 64 slice scanner (79.75±1.69, 1598.8±110.8 and 3.35±0.23) respectively. It was significantly lower in 32 and 16 slice multi detector CT (69.54±4.74, 986.9±72.17 and 2.07±0.15) (54.21, 943.8±21.74, and 1.98±0.045) respectively. Regarding image quality assessment, the SNR and CNR are compared among multiple groups of patients examined in three types of MDCT. In regard to SNR, in our study it is noted that there are no significant differences among brain groups and chest groups according to the three multi-detector rows of 16-MDCT, 32-MDCT, and 64-MDCT. Where, the determined means of SNR and P-value of brain groups are (11.5±1.35, 11.75±4.13, 12.3±5.61, and 0.9) and for chest While, the determined means of SNR and P-value of chest groups are (3.83±0.76, 4.18±1.35, 5.92±3.1, and 0.05) respectively.Conclusion: The mean value of radiation doses (CTDIv in mGy, DLP in mGy.cm and ED in mSv) higher in 64 than 32 and less than that in 16 in chest and brain CT scan. While the image quality was higher in higher CT multi-detector rows, it is non-significant in chest and brain CT exam.