CT KUB scans for renal colic: Optimization of scan range to reduce patient radiation burden.

Abstract

Objective: To optimize the scan range of CT KUB scans for renal colic to reduce patient radiation while maintaining diagnostic accuracy. Study Design: Cross-sectional study. Setting: Department of Radiology, Tertiary Care Hospital, Sargodha. Period: January 2024 to June 2024. Methods: A total of 95 adult patients (age ≥ 18 years) who received CT KUB due to the suspicion of renal colic with complete imaging data were included. Data collection encompasses demographic information (age, gender) and CT scan parameters (scan range, slice thickness, and radiation dose). Scan range optimization involved reviewing CT images to determine the optimal range covering kidneys, ureters, and bladder. Radiation dose metrics, including the dose-length product (DLP) and effective dose were measured for each CT KUB scan following standard protocols and utilizing dose estimation software. The collected data were subsequently processed and analysis was done via the use of IBM SPSS version 27.0. Results: Among the 95 scans analyzed, 51 (53.7%) were female and 44 (46.3%) were male, with a mean patient age of 43.8 ± 14.6 years. Only 27 scans (28.4%) had less than 10% overscan above the highest kidney target, while 68 scans (71.6%) exceeded this threshold. The mean total scan length was 454 mm (SD = 53.6 mm). The mean overscan above the kidney measured 64.5 mm (SD = 22.2 mm), accounting for 14.3% of the total scan length. Over-scanning ranged from 16 mm (3.9%) to 123 mm (33.2%). Conclusion: This study validates initiating the CT KUB scan at the upper border of the T11 vertebra and concluding at the symphysis pubis to minimize unnecessary radiation exposure while preserving diagnostic accuracy. This optimized scan range effectively reduces over-scanning and enhances patient safety.