Head CT Dose Examination for Adult Patient in Abuja and Keffi, Hospitals in Nigerian

Abstract

This study has established local diagnostic reference levels (LDRLs). Dose report and scan parameters for the head was assessed during seven months at the three study centres. Data on CT Dose index (CTDIw) and dose length product (DLP) available and achieved on CT scanner control console was recorded for a minimum of 10 average-sized patients for each facility to establish a local Diagnostic reference level (LDRLs) and radiation dose optimization Data was collected using a purposive sampling technique, from 131 adult patients weighing 70±3kg) from Philip brilliance, Toshiba Alexion and General Electric (GE) CT scanners for this study. The collected data were analyzed using SPPSS version (20) statistical software. Third quartile values of the estimated LDRLs for CTDIw and DLP was determined as 49.8 mGy and 9639 mGy. The mean CTDIw obtained are lower to the reported data from the European Commission of 60mGy. The mean DLP are comparably lower than all the reported value from the European commission of 1050 mGy. Therefore, CT dose optimization is recommended.

Untitled

“…In Nigeria, some authors have established DRLs both locally as per state, and regionally as per geographical zones (Tables 8,9 and Figures 6,7). The results of our study were compared with the works of Buhari [18] from Northwest with CTDIv and DLP (17.25mGy/735mGy.cm) and percentage variation with our work as 21.7% and 21.4% respectively. In a similar study, in Northcentral, Rilwan et al, [19] obtained 10.9 mGy/432.8mGy.cm for CTDIv and DLP and variation with our work shows 13.7% and 12.6% respectively.…”

“…CT dose index (CTDI (mGy)), which is the measure of the dose from single-slice irradiation is defined as the integral along a line parallel to the axis of rotation (z) of the dose profile, D(z), divided by the nominal slice thickness, T as shown in Equation 1 [23].…”

“…The weighted CT air kerma index, CTDIw (mGy), used to combine values of CTDI measured at the centre (c) and periphery (p) of a standard CT dosimetry phantom as shown in Equation 2 [23].…”

“…Where N is the number of scans, T is the nominal scan width (mm) and L is the distance between scans (mm) [23].…”

“…The International Commission on Radiological Protection (ICRP) recommended that Diagnostic Reference Levels (DRLs) should be used by regional, national and local authorized bodies like Nigeria Nuclear Regulatory Authority (NNRA), so as to minimized the patient doses from unnecessary exposure by keeping all patient exposures to as low as reasonably achievable (ALARA Concept) [15,16]. In CT examinations, the volume Computed Tomography Dose Index (CTDIv) and Dose Length Product (DLP) are the parameters used to estimate the dose to the standard phantom representing average patients [17,18]. The CTDIv represents the average dose to a cross section of a phantom (measured in mGy) [6,7].…”