Analysis of Effective Dose at Computed Tomography in a Modern 64 slice Multidetector CT System in an Irish Tertiary Care Centre with Local and International Reference Standards

Diagnostic Reference Levels (DRLs) are used to establish if local imaging protocols have been optimised. This study examines a modern multi-detector 64 slice CT (MDCT) system for four commonly performed examinations in a large tertiary care centre by comparison with current international reference standards. Effective dose (ED) was calculated using dose-length product conversion coefficients for all patients and compared to Irish national and local DRLs, and published international point values. ED at CT abdomen-pelvis was 28.5% above the national DRL and 26% above the local DRL. ED at CT thorax was 3.5% greater than local DRL and 42.5% greater than the national DRL. ED at CT brain was 100% above both the local and national DRLs. CT cervical spine ED was 79% greater than the local and 100% greater than the national DRL.A review of study protocols is necessary to facilitate optimisation of total study radiation dose.