Estimation of indication-based diagnostic reference level and developing optimized protocols for Abdominopelvic CT

This research protocol aims to optimize radiation dose in abdominopelvic CT imaging by establishing clinical indication-based diagnostic reference levels (CIDRLs) rather than traditional anatomy-based DRLs. Conventional DRLs are limited because the same anatomical region can include multiple clinical indications that require different scan phases and exposure levels, leading to variations in patient dose. The study addresses this gap by focusing on four key indications—CT Urography, CT Enterography, CT Pancreas, and CT KUB follow-up—using a 128-slice CT scanner. In Phase 1, indication-specific DRLs will be estimated prospectively from adult patients, with dose metrics (CTDIvol, DLP, ED) and image quality (SNR, CNR, noise, and qualitative scoring) assessed. In Phase 2, optimized protocols will be developed by tailoring scan parameters such as kVp, mAs, scan coverage, and phases based on patient BMI and clinical indication, followed by comparison with baseline protocols to validate improvements. A pilot study indicated that CT Urography delivered the highest radiation dose, highlighting the urgent need for dose reduction. The expected outcomes include institution-specific CIDRLs, optimized abdominopelvic CT protocols, and baseline data for future regional or national studies. Clinically, this work will improve patient safety by reducing unnecessary radiation exposure, enhance diagnostic efficiency, standardize imaging practices, and support regular audits in line with ALARA principles.