Developing an Evidence-Based Theoretical Model for Radiation Dose Justification in Emergency CT Examinations at Nigerian Tertiary Hospitals

Radiation dose justification in emergency CT examinations involves a clinical decision process balancing diagnostic benefit against radiation risk that is influenced by clinical urgency, decision-maker knowledge, institutional protocols, and medicolegal contexts that operate differently in Nigerian tertiary hospitals than in the high-income healthcare settings from which existing justification models are derived. This study develops an evidence-based theoretical model for radiation dose justification in emergency CT specifically for Nigerian tertiary hospital contexts. A multi-phase design combines: retrospective audit of 800 emergency CT referrals across eight tertiary hospitals for appropriateness classification using iRefer and clinical outcome correlation; prospective think-aloud protocol study recording justification decision-making processes of 50 emergency physicians and radiologists across four hospitals; dose-benefit analysis using risk-benefit Monte Carlo modelling with Nigerian population-specific cancer incidence rates; and iterative expert panel refinement of the model using nominal group technique. The original Emergency CT Justification Model for Nigerian Tertiary Contexts specifies the decision pathway, justification threshold criteria, shared decision-making protocols, and governance documentation standards adapted to the Nigerian context. The model identifies seven Nigerian-specific justification modifiers, including security conflict-related trauma prevalence and CT as first-line investigation for seizures in a malaria-endemic context, that differentiate the justification criteria from imported models. Available CT justification literature from Nigeria identifies the over-application of international justification criteria without Nigerian clinical prevalence data as the primary model validity concern. The ICRP justification framework and Evidence-Based Medicine methodology provide the theoretical reference. Keywords: radiation dose justification, emergency CT, Nigerian tertiary hospitals, theoretical model, dose benefit analysis.