Estimation of effective dose for contrast and non-contrast head computed tomography using dose length product and k conversion coefficient for adult patients in SouthSouth Nigeria

Abstract

The aim of this study is to estimate the effective dose of contrast and non-contrast computed tomography (CT) head examinations using Dose-Length Product (DLP) and conversion coefficient (k). The DLP for 462 adult patients referred for head CT examination (contrast and non-contrast) from four centres (A1, A2, A3 and A4) in Delta and Edo States were collated and the effective dose for head CT of contrast and non-contrast examinations was estimated by multiplying the dose length product by
the k conversion coefficient (0.0021 mSv∙mGy−1∙cm−1). The minimum, maximum, standard deviation, mean, 50th percentiles (median) and 75th percentiles were analysed using statistical package for the social sciences (SPSS) version 22.0. The 50th percentile (median) of the effective dose was compared with values published by other researchers in Nigeria, Africa, European Commission, Germany, Italy, Taiwan, Canada and Japan. The estimated effective dose for non-contrast CT head examinations for
centres A1, A2 A3 and A4 were 3.7, 1.0, 0.8 and 1.3 mSv, respectively. The estimated effective dose for contrast CT head examinations for centres A1, A2, A3 and A4 were 6.9, 1.8, 1.4 and 3.1 mSv, respectively. The estimated effective doses were at par with other published studies for non-contrast examinations. Further optimization of scan protocols is required for contrast examinations.