Organ dose and lifetime attributable cancer risk from abdominal CT examinations: A multicentre retrospective study in Jordan

OBJECTIVE: To quantify effective dose (ED), organ doses, and lifetime attributable risk (LAR) from adult abdominal CT, and assess age- and sex-related variation. METHODS: ) and dose length product (DLP)) were extracted from PACS. Organ doses were calculated using the Monte Carlo based VirtualDose™ platform, and ED was estimated from DLP using an anatomy appropriate conversion coefficient. LAR for cancer incidence and mortality was estimated using age- and sex-specific Biological Effects of Ionising Radiation (BEIR) VII risk models. RESULTS: Mean ED varied modestly across age bands and sexes, with a cohort mean of 12.95 mSv. The liver consistently received the highest absorbed dose (20-30 years: 33.68 mGy; 70-80 years: 32.00 mGy), while stomach and colon doses were similar across age bands (10.67-11.23 mGy). LAR showed a clear age gradient, with the highest values in 18-20 years and the lowest in 70-80 years for both sexes. Females had higher stomach LAR and males higher colon LAR. Despite higher liver dose, the colon had the highest projected LAR, reflecting organ-specific risk coefficients. CONCLUSION: Younger adults have higher lifetime cancer risk from abdominal CT despite broadly similar ED across age bands, suggesting that the age gradient is biologically driven rather than dose-driven. These findings support strengthened justification, age- and sex-specific protocol optimisation, and systematic dose auditing to minimise radiation exposure while maintaining diagnostic performance.