*Biophysic and Medical Imaging Departments, Campus Teaching Hospital, University of Lome, Togo
**Radiology Department, Campus Teaching Hospital, University of Lome, Togo
***Radiology Department, North Ardennes Intercommunal Hospital, Charleville-Mezieres, France
The purpose of this study is to evaluate the doses delivered to adult patients during CT examinations in order to establish CT diagnostic reference levels (DRL) in Togo. It was a cross-sectional study conducted from March 6 to July 30 2016 in all health facilities with a CT unit in Togo. The study included cerebral, thoracic, abdominopelvic, thoracic abdominopelvic (TAP), cervical and lumbar spine CTs of patients aged 15 years and over. The 1,155 adult CT scans were dominated by cerebral and abdominopelvic CTs with 34.2 % and 15.15 %, respectively. The sex ratio (men/women) was 1.42. The brand of the CT scan equipment was in 80 % of cases General Electric. All CT scan machines were either 6 or 16 bars and 60 % of them were installed in 2010. The CT dose index (CTDIvol) of cerebral CT was the highest compared to the CTDIvol of the other types of examination. The dispersion of DLPs per acquisition and for a complete examination was significant within and between health facilities. The DRLs (75th percentile of DLP) per acquisition were 1,199.14 mGy·cm (non-traumatic cerebral), 1,596.45 mGy·cm (traumatic cerebral), 635.63 mGy·cm (cervical), 401.98 mGy·cm (thoracic), 594.42 mGy·cm (abdominopelvic), 675.73 mGy·cm (thoracic abdominopelvic) and 681.35 mGy·cm (lumbar). The mean effective doses associated with the different types of examinations ranged from 2–3 mSv for head and neck exposure, to 24 mSv for abdominopelvic CT. The wide dispersion of dose delivered during CT in Togo requires a process of homogenization of procedures and optimization based on DRLs thus determined.
Key words: CT dose index, dose length product, diagnostic reference levels, CT scan
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