Patient dose estimation in CT examination using dose conversion coefficient method and CT -expo software

The quantity of radiation delivered to patients undergoing computed tomography (CT) examination is the first step in the optimization of patient dose.

The purpose of this study was to estimate and validate adult patient dose during CT examination at the Greater Accra Regional Hospital, Ridge-Accra by using conversion coefficient and CT-Expo software. Organ and effective doses for 150 patients undergoing head, chest and abdominopelvic examinations were estimated using DLP to effective dose conversion coefficient method and CT-Expo software. Mean organ dose estimated using CT-Expo software were compared with other international published data. Organ dose from this study were generally lower as compared to organ dose values from other studies. The eye lens received the highest mean organ dose of 38.81 ± 5.01 mGy whilst the heart received the lowest mean organ dose of 5.26 ± 2.03 mGy. No statistical differences (p ≤ 0.051) were observed between the median effective doses estimated from the two methods for the chest and abdominopelvic CT examinations. Significant (p = 0.001) differences were observed between the median effective dose estimated by the two techniques for the head examination. The median effective dose for DLP to effective dose conversion coefficient (k-coefficient) method and CT-Expo software for the head CT were 1.605 and 2.00 mSv respectively. The mean organ dose per each CT examination from this study were generally comparable with those from other published data.