Evaluation of Absorbed Dose and Protocols During Brain Computed Tomography Scans in a Nigerian Tertiary Hospital

Computed tomography (CT) scan of the brain is the commonest CT examination performed and had been recognized to deliver very high radiation dose to the patients. This study was aimed at evaluating the radiation dose from routine brain CT scan and to compare the dose from the protocols for brain CT. The ex-postfacto design was adopted. All the records of brain CT scan from September 2011 to August 2015, acquired with a 16 slice CT machine (Phillips Brilliance Medical System, MX8000) in the Radiology Department of University of Maiduguri Teaching Hospital (UMTH) were evaluated. Ethical approval was obtained from the Ethical Committee of UMTH. The weighted CT dose index (CTDI ), volume CT dose index (CTDI ) and dose length w vol product (DLP) values were recorded for each of the examination. Results showed that the two main protocols used were axial and helical scan modes. The mean CTDI and DLP values were 76.6 mGy and 1285.8 mGy*cm vol for axial and 103 mGy and 1903 mGy*cm for helical scan modes respectively. There was a significant difference (p < 0.05) between the CTDI and DLP values of axial and helical scan modes. Conclusion: the study found vol higher radiation dose in helical than axial scan modes. This study therefore recommends the use of axial scan mode for routine brain CT scan, to reduce radiation dose, except where speed is desirable such as in unconscious patients, uncooperative patients and when automatic injector pump is to be used.