ESTABLISHING LOCAL DIAGNOSTIC REFERENCE LEVELS FOR ROUTINE COMPUTED TOMOGRAPHY EXAMINATIONS IN JIMMA UNIVERSITY MEDICAL CENTER SOUTH WEST ETHIOPIA

The main purpose of this study was to determine local diagnostic reference level (LDRL) for Routine Computed Tomography (CT) examination in, Jimma University Medical Center (JUMC) South West Ethiopia. Retrospective study was conducted to determine LDRL for routine CT examination in JUMC. We have considered CTDIvol and DLP as dosimetric quantity based on the recommended guidelines to determine LDRLs by different international legal Authorities. The 75(th) percentile values of the calculated CTDIvol and DLP were proposed as LDRL. LDRL was obtained as CTDIvol, 42.97mGy, 7.76mGy, 14.32mGy, and 10.86mGy for routine brain CT, routine chest CT, routine thoraco-lumbar CT and routine abdomen CT examination respectively. Similarly the determined LDRL from DLP was 1364.15mGycm, 368.96mGycm, 853.18mGycm, and 1568.96mGycm for brain, chest, thoraco-lumbar and abdomen examination respectively. The LDRL obtained for DLP was higher compared with international DRLs; it can be reduced by coordinating effort between radiologists, technologists and medical physicist.