Tehran University of Medical Sciences Frontiers in Biomedical Technologies 2345-5837 12 3 2025 07 01 635 646 Sadegh Shurche Department of Medical Physics, Faculty of Medicine, Tarbiat Modares University, Tehran, Iran Nima Rostampour Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran Tinosh Almasi Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran Roghiye Bodaghi HosseinAbadi Department of Medical Physics, Faculty of Medicine, Tarbiat Modares University, Tehran, Iran Omid Sadeghi Department of Medical Physics, Faculty of Medicine, Tarbiat Modares University, Tehran, Iran Maryam Tima Medical Imaging Department, Chamran Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran 2023 06 18 2023 09 05 Purpose: The aim of this study is to investigate the diagnostic reference levels (DRL) for the abdomen-pelvis computed tomography (CT) examinations performed at our medical institution. Materials and Methods: In total, the data of 600 patients referred to the radiology center of Chamran hospital in Kermanshah from May 1, 2022, to May 1, 2023, were collected. All scans were performed using a GE Healthcare 16-slice. Four imaging protocols have been used for imaging the abdomen and pelvis of patients, which include without contrast media, with oral contrast media, with contrast media injection, and triple-phase. The volume CT dose index (CTDIvol (mGy)) and dose length product (DLP) distribution’s median and 75th percentile values were computed. Results: Effective dose values in the triple-phase ranged from 33.30 to 38.12 ± 0.1 mSv for patients with different DLP values, for without and oral contrast media ranged from 8.68 to 9.45 ± 0.2 mSv, for with contrast media injection ranged from 10.83 to 11.45 ± 0.1 mSv based on the total value of DLP. We established our DRLs as the median value of CTDIvol (mGy)| and DLP (mGy.cm) as follows: abdomen and pelvis CT without contrast media and oral contrast media: 12 mGy and 605 mGy.cm, respectively; CT abdomen and Pelvis procedure (triple-phase): 11 mGy and 2382 mGy.cm, respectively; abdomen and pelvis CT with contrast media injection protocols: 16 mGy and 1484 mGy.cm, respectively. Conclusion: The proposed DRL values for all imaging protocols are slightly higher than the European and the American College of Radiologists (ACR) DRL values in DLP and CTDIvol (mGy). The purpose of DRL in terms of CTDIvol (mGy) is comparable with the international guidelines. Thus reducing the scan length is recommended ensuring that patients receive a minimal possible radiation dose while maintaining the image quality. https://fbt.tums.ac.ir/index.php/fbt/article/view/741 https://fbt.tums.ac.ir/index.php/fbt/article/download/741/513