Empirical Study of Dose-Length Product Trends in CT Abdomen and Pelvis Examinations at Teaching Hospitals in North Central Nigeria

CT abdomen and pelvis examinations represent the highest collective radiation dose category in Nigerian teaching hospital CT departments, yet systematic empirical analysis of dose-length product trends and their determinants across North Central Nigeria is absent from the published literature. This study empirically analyses DLP trends and identifies significant predictors of dose variation in CT abdomen and pelvis examinations at teaching hospitals in Plateau, Kogi, and Kwara States. A retrospective dose analysis reviews 600 CT abdomen and pelvis examination records (200 per state) from University of Jos Teaching Hospital, Federal Medical Centre Lokoja, and University of Ilorin Teaching Hospital for 2021 to 2023. DLP values, scan parameters, patient size indicators, and protocol variables are extracted and entered into a multilevel regression model in R to partition dose variation across patient, protocol, and institutional levels. Available CT abdomen dose literature from North Central Nigerian hospitals identifies wide inter-institutional DLP variation of up to 4-fold, primarily attributable to protocol-level differences rather than patient size differences. The European CT diagnostic reference levels and IAEA DRL methodology provide the analytical benchmarks. Findings are expected to identify protocol-level variables as the dominant predictors of DLP variation, providing clear optimisation targets. Recommendations address inter-institutional CT protocol harmonisation, automated DLP monitoring, and a North Central Nigeria CT dose governance group. Keywords: CT abdomen, dose-length product, teaching hospitals, North Central Nigeria, dose optimisation.