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

Document Type : Original Paper


Medical Physics and Radiology Department, Faculty of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran


Introduction: Many numbers of abdominopelvic CT scans are performed in extra phases while having no specific clinical indication, resulting in extra radiation dose to the patient. 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.

Methods and Materials: A total of 163 patients, 85 patients with single phase and 78 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. 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 9.8 mGy and 571, respectively. There was no statistically difference between single phase and double phase imaging in terms of CTDIvol and SSDE (p > 0.05). The mean value of E was 5.4 ± 1.8 and 10.3 ± 3.4 for single phase and double phase imaging, respectively, resulting in 4.9 mSv excess dose per patient. Mean value of the DLP was 396.9 ± 142.7 and 759.0 ± 250.7 for single phase and double phase imaging, respectively. E was significantly higher in female compared to male (p < 0.05). 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.


Main Subjects

Articles in Press, Accepted Manuscript
Available Online from 20 June 2022
  • Receive Date: 16 March 2022
  • Revise Date: 20 May 2022
  • Accept Date: 20 June 2022
  • First Publish Date: 20 June 2022