Establishment of Diagnostic Reference Levels and Evaluation of Radiation Dose in Double Phase Abdominopelvic Computed Tomography

Introduction: The purpose of this study was to establish of diagnostic reference level (DRL) and to compare radiation dose between single phase and unjustified double phase abdominopelvic CT imaging. Material and Methods: A total of ۱۶۳ patients, ۸۵ patients with single phase and ۷۸ patients with unjustified double phase abdominopelvic CT scans, were included in this retrospective study. Volumetric CT dose index (CTDIvol) and dose length product (DLP) were obtained from the CT console. The third quartile of CTDIvol and DLP were determined for diagnostic reference level (DRL). Effective dose (E) and organ dose were obtained using CT-Expo software (version ۲.۲). Single phase and double phase scans were compared in terms of CTDIvol, DLP, size-specific dose estimate (SSDE), E and organ doses. Results: The institutional DRLs using CTDIvol and DLP for abdominopelvic CT were ۹.۸ mGy and ۵۷۱ mGy.cm, respectively. The mean value of E was ۵.۴ ± ۱.۸ and ۱۰.۳ ± ۳.۴ for single phase and double phase imaging, respectively, resulting in ۴.۹ mSv excess dose per patient. Mean value of the DLP was ۳۹۶.۹ ± ۱۴۲.۷ and ۷۵۹.۰ ± ۲۵۰.۷ for single phase and double phase imaging, respectively. E was significantly higher in female compared to male (p < ۰.۰۵). Bladder has a highest lifetime attributed risk of cancer incidence among other organs. Also, the cancer risk incidence was higher for female than male. Conclusion: The awareness of physicians about the correct indications of abdominopelvic CT should be increased by using associated reliable guidelines

Keywords:

Computed Tomography , Effective Dose , abdomen , Pelvis , Justification