NATIONAL DIAGNOSTIC REFERENCE LEVELS AND ACHIEVABLE DOSES FOR STANDARD CT EXAMINATIONS IN SUDAN

Radiation doses were determined to propose national diagnostic reference levels (NDRLs) and achievable doses (ADs) for computed tomography (CT) examinations in Sudan. Doses were estimated from retrospectively collected scan parameters for 1336 CT examinations of adult patients from 14 Sudanese hospitals using CT Expo 2.5 software. ADs and NDRLs were set at the 50th and 75th percentile of the hospital median dose distribution, respectively. The proposed CTDIvol (mGy) ADs ranged from: 10 (chest) to 64 (head), and that of the dose-length product (DLP; mGy.cm) ranged from 366 (chest) to 1225 (head). The proposed CTDIvol (mGy) NDRLs ranged from 15 kidney-ureter-bladder (KUB) to 79 (head), whereas that of the DLP (mGy.cm) ranged from 690 (chest) to 1490 (head). Current doses fell within the upper range of the doses presented in the literature emphasizing the need for implementation of the current ADs and NDRLs for CT to enhance patient protection and dose optimization in Sudan.

RADIATION DOSE DETERMINATION IN ABDOMINAL CT EXAMINATIONS OF CHILDREN AT SUDANESE HOSPITALS USING SIZE-SPECIFIC DOSE ESTIMATES

In this study, we thought to estimate the radiation exposure of children undergoing multi-detector CT examinations using size-specific dose estimates (SSDE). Console-displayed volume computed tomography dose index (CTDIvol) were recorded for a total of 78 paediatric abdominal CT examinations performed in six hospitals. Measurements of the patient diameters were taken from the mid-slice location on the transverse and scout CT images. Size-specific conversion coefficients were used to translate CTDIvol to the SSDE, according AAPM Report 204. For children aged 0-1 y, CTDIvol, SSDEtrans (from transverse images) and SSDEsco (from scout images) were: 12.80 ± 16.10, 14.43 ± 13.22; and 14.37 ± 13.03 mGy; respectively. For children aged 1-5 y, CTDIvol, SSDEtrans and SSDEsco were: 12.11 ± 14.47, 18.8 ± 18.61 and 16.51 ± 13.55 mGy; respectively. The obtained doses are higher than the corresponding diagnostic reference levels. SSDE increase with patient size as results of tube current modulation and is therefore a valuable tool for dose optimisation.