Computed Tomography Dose for Adult Head Scan in Anambra State of Nigeria

Abstract

Background: Computed tomography is associated with relatively high radiation doses and could cause serious health risks. Globally, it is reported that many physicians do not to have adequate knowledge about CT dose. Furthermore, although dose records are available from developed countries, there is a paucity of literature in Nigeria. Dose outputs in our locality are also scarce in the literature.

Objective: To review adult head CT dose in the four largest centres in Anambra State.

Methodology: A 6-month retrospective retrieval of dose summary from the control console. Digital folders of subjects ≥ 18 years were sampled purposively and sequentially, out of the 2015 population of CT examinations. The CTDIvol and DLP for each case were recorded in a pro forma. The mean dose in each centre as well as the combined mean for all centres were calculated. The results were compared with the recommendations of the European Commission and similar studies from Nigeria.

Results: The digital folders of 200 subjects made up of 104 (52.0 %) males and 96 (48.0%) females with an age range of 18 – 93 years were involved in the study. Cranium (n = 164; 82 %) dominated the CT requests. The mean CTDIvol and DLP in the four centres was 58 mGy and 1112 mGy.cm. The mean CTDIvol (73 mGy) and DLP (1613 mGy-cm) in one of the centres was extreme. When excluded, the mean CTDIvol and DLP for the remaining three centres were 52 mGy and 945 mGy.cm, respectively.

Conclusion: Dose output in Anambra State was comparable to the recommendation of the European Commission but varied significantly from other local studies. The establishment of diagnostic reference levels for CT procedure in the locality is imperative.