Establishment of national diagnostic reference levels as guidelines for computed tomography radiation in Jordan

Computed tomography (CT) scan contributes to about 10% of the total medical radiographic examinations conducted worldwide. Noticeably, various studies have raised concern regarding the high radiation dose exposure of patients during this technique of imaging. The study assesses the dose of radiation to which patients undergoing different CT examinations in Jordanian hospitals are exposed and measures the national diagnostic reference levels (DRLs). This retrospective observational study of all CT examinations performed in almost 300 plus CT examination centers in Jordan. A random sample of the top 28 hospitals in Jordan was taken for the study, which was conducted between May 2019 and December 2020. We quantified the national DRL by calculating the 75th percentile and the percentage difference of volume CT dose index (CTDIv) and dose length product (DLP) for both pediatric and adult populations and different CT examinations, including brain, sinus, chest, abdomen & pelvis, knee, neck, lumbar-spine, cervical-spine, and shoulder. A total of 242 pediatric patients and 304 adult patients underwent various CT examinations during the study period. The national DRLs (the 75th percentiles of CTDIv and DLP) for the pediatric population were highest for the brain (81 mGy and 1425 mGy.cm, respectively) and lowest for the shoulder (7 mGy and 181 mGy.cm, respectively). Similarly, the 75th percentiles of CTDIv for the adults were highest for the brain examination (68 mGy) and lowest for the shoulder (8 mGy). The national DRLs for CT scans conducted in Jordan hospitals were found to be higher than those quantified in other countries, with larger CTDIv and DLP variations.