Patient doses during radiography and CT examinations in Tanzania: Preliminary results

The aims of this study were to determine the average doses during radiography and CT examinations of adult patients in Tanzania and to compare doses with international diagnostic reference levels (DRLs). Do ses to 10 adult patients weighing between 65 to 80 kg were estimated at each of 14 radiography facilities in terms of entrance surface air kerma measurements (ESAK) using incident air kerma measurements and patient expos ure parameters. CT doses were estimated at 6 facilities in terms of weighted computed dose index (CTDIw) and dose length product (DLP) using ImPACT CT dose calculator (UK) on basis of patient exposure parameters. The results show that the mean ES AK varied from 0.16 to 0.38 mGy (chest PA), 1.83 to 7.02 mGy (lumbar spine AP), 3.0 to 7.02 mGy (lumbar spine lateral), 0.36 to 4.14 mGy (abdomen AP) and 0.4 to 1.9 mGy (pelvis PA). The mean CTDIw ranges were 28.7-69.7 mGy (head), 14.2-25.4 mGy (chest), 19.4-39.1 mGy (lumbar spine) and 14.2-25.4 mGy (abdomen). The corresponding mean DLP values varied from 456 to 1372, 276 to 1619, 140 to 867 and 379 to 968 mGy·cm respectively. All im ages ass ociated with the reported doses were use d for diagnosis. The res ults indicate that the current average patient doses of the majority examinations at studied facilities are below the recommended DRLs