Assessment of Volumetric Computed Tomography Dose Index (CTDIvol) for selected computed tomography scanners in Uganda

Abstract

The Atomic Energy Council conducted routine inspections on 42 facilities with Computed Tomography (CT) scanners in Uganda to verify the compliance of their CTDIvol with the established regulatory machine performance standards. The findings of the inspections revealed that most scanners complied with the recommended regulatory dose limits for the adult abdomen, adult head, and pediatric abdomen examinations. The mean optimal doses deduced from the study were 5 mGy, 15 mGy, and 50 mGy for pediatric abdomen, adult abdomen, and head examinations respectively. However, a considerable number of scanners, 4%, 6%, and 20% produced doses exceeding the regulatory limits for pediatric abdomen, adult abdomen, and adult head respectively. It was established that some of the corrective actions for scanners that produced high doses exceeding the regulatory limit were (1) varying of tube current parameters, and (2) varying of pitch. The scanners Y and Z produced exceedingly very high doses compared to the regulatory limit and were recommended for immediate suspension to correct for the dose irregularity. The study also established that about 50% of CTs were of the modern era with improved technologies of dose optimization and minimization. However, the operators had limited access rights to interact and utilize these technological advancements. It was therefore, recommended that all stakeholders involved in supplying, acquiring, and operating these machines to ensure that the end users (radiation workers) acquire adequate end-user training and retraining programs. We also recommend the facilities to perform acceptance and commissioning tests and periodic quality control tests to ensure compliance of the CT machines with the regulatory dose limits.