A survey of paediatric CT radiation doses in two selected hospitals in Kampala, Uganda: a radiation safety concern

Abstract

Purpose: We describe radiation doses imparted to paediatric patients during Computerised (CT) scan examinations by estimation Weighted CT dose index (CTDIw) and Dose Length Product (DLP) and compare these doses with the International dose reference values.Methods: Demographic data and acquisition parameters of 257paediatric CT scans done using Multi-Slice CT (MSCT) and Dual Slice CT (DSCT) were collected from request forms and CT scan consoles. The values of CTDIw, CTDIvol and DLP were calculated using ImPACT (Imaging Performance and Assessment of Computed Tomography) dosimetry software for Philips MX-1800 scanner and GE Hispeed Dual scanner. Data was analysed using mean, range, 3rd quartile, as well as chi square.Results: The commonest indication was head injury with the majority patient aged 0-4 years and 10-14 years for MSCT and DSCT, respectively. There were significantly higher doses imparted by MSCT compared to DSCT on both the head CTDIw (mGy) (40 vs 22, p = 0.000), CTDIvol (mGy) (60 vs 7, p = 0.000), DLPmGy.cm (1022 vs 114, p = 0.000) and body CTDIw (mGy) (41 vs 18, p =0.000), CTDIvol (mGy) (27 vs 6 p-value=0.000) and DLP (782 vs 73 p-value=0.001) respectively. Paediatric 3rd quartile values for CTDIvol (mGy) (57.7 vs 31) 0-1 year, (74.5 vs 47) 4-7 years and DLP mGy.cm (1068 vs 333) 0-1 year and (1168 vs 374) 4-6 years respectively for MSCT were higher than the recommended international values. The calculated CTDIvol for the head were significantly higher than the values displayed on the console (p-value=0.000, 95%CI) for MSCT.Conclusion: The radiation dose values for CTDIw, CTDIvol and DLP for MSCT were significantly higher than those for DSCT and other countries which raise a radiation safety concern. Studies to establish the factors responsible for these high doses are recommended.</p