Dr.Teferi, Seife(PH.D. Medical Physicist)Dr.Zewdneh, Daniel(MD, Consultant Pediatric Radiology)Dr. Getnet, Wondim(MD, Consultant Body Radiologist)Zegeye, Gebretsadik2020-02-112023-11-052020-02-112023-11-052019-10http://etd.aau.edu.et/handle/123456789/20602Background: The use of CT in medicine is now firmly established and represents one of the most important radiological procedures performed worldwide. CT is a major source of radiation exposure and provides a substantial proportion of the collective dose from medical exposure. Objective: To investigate routine abdominal/pelvic CT radiation doses in Tikur Anbessa Specialized Hospital (TASH), Ethiopia in 2018. Method: A hospital-based retrospective cross-sectional study was conducted from February 1, 2019 to April 30, 2019, at TASH. The study was conducted among all abdominopelvic CT scans performed in TASH in 2018. After counting the total abdominal/pelvic CT scans, a systematic random sampling method (taking every K th ) was employed to select study subjects from the image registry (medweband workstation) which contain all performed CT scans. Data were collected from a total of 348 abdominal/pelvic CT scans using a structured data collection format by the principal investigator. Finally, data were entered into EpiData version 3.1 and exported to SPSS version 24 software for analyses. Text, tables, and graphs were used to present descriptive data, and analysis was processed. Result: The mean CTDIvol values of pediatric abdominopelvic CT scans for ages <1yr , 1-5yr, 510yr and 10-15yr, respectively, were 6mGy (IQR, 3-7mGy), 4.9mGy (IQR, 3.3-6.8mGy), 4.4mGy (IQR, 4.2-4.6mGy), 4.7mGy (IQR, 3.3-5.1mGy). In adult abdominopelvic CT scans, the mean CTDIvol value was 11mGy (IQR, 7–14 mGy) while the mean DLP for single phase, multi-phase and all examinations, respectively, were 593mGy.cm (IQR, 252-1579 mGy.cm), 1759 mGy.cm (IQR, 9782268 mGy.cm), and 1180 mGy.cm (IQR, 473-1557 mGy.cm) and the mean effective doses for singlephase, multiphase, and all examinations, respectively, were 8.9 mSv (IQR 5.3-10.8), 26.2 mSv (IQR, 14.3-32.7 mSv), and 17.6 mSv (IQR, 7.1-23.2 mSv). Radiation doses of multiphase examinations were approximately two to three times that of the single-phase examinations. Pediatric radiation doses were 20-25% of those of adults. The mean CTDIvol dose values of our hospital procedures are lower or comparable to those reported internationally except for the two younger age group pediatric patients, which have higher values than other DRLs. Additionally, the DLP and effective doses are considerably higher than those reported international DRLs in comparison to the CTDIvol. Conclusion: Higher doses are primarily due to the consistent problem of poor scan length collimation all ages and both higher tube voltage and longer scanning length in the two younger age group pediatric patients. Thus, the scanning length should be reduced to the needed minimum for the examination in all ages and lower tube voltages shoud be used in the two younger age group pediatricpatients.en-USAbdominal,pelvic ,CT radiationThesis