Abstract

The field of radiology is still evolving and Computed Tomography (CT) is a specialized modality in medical Radiography. Computed Tomography (CT) scan of tissues, organs, bones, and vessels of the body provides doctors with a much clearer picture of what is happening inside the body than conventional X-rays. This paper is organized around determining the safe paediatric Computed Tomography (CT) Reference Range for head scans in Rivers State, Nigeria, where no previous research has been conducted. It analyzes six paediatric CT scanning centers in Port Harcourt, Rivers State for children aged 0 to 18 years using a retrospective and prospective research design. Using the z-scores for unlimited population, a sample size of 100 was determined at random from National Population Commission data on Rivers State paediatric residents. The children were grouped according to their ages into four viz Group 1 (˂1-˂5 yrs); Group 2 (5-<10 yrs); Group 3 (10-<15 yrs) and Group 4 (15-<19 yrs).  The Kruskal-Wallis statistical rank test and the Kolmogorov-Smirnov test of normality were used to calculate results of the Computed Tomography dose index CTDI_vol (mGy) and dose length on head scans at the 75th percentile.  This study determined that CTDI_Vol is 45.84 -54.08 (mGy) while DLP is 44.95 – 54.81 (mGy.cm). A maximum of 1 millisievert (mSv) per scan and cumulative dose not exceeding 5 mSv per year is a reasonably achievable radiation dose stipulated by U.S. Department of Health and Human Services. The study’s findings suggest that if the CT machines were of higher slices (64slices and above) the radiation dose could be reduced further.  Using a scaling factor of 0.623 and a conversion factor of 0.017 to convert the CTDIw value to the effective dose, we concluded that a patient will be exposed to a total dose of 2mGy for a CT scan length of 200mm. The study supports the use of a CT scanner with higher slices (64slices and above) in order to advance research on the reference dose for pediatric CT scans.