Assessment of cancer incidence and mortality risks associated with effective dose of computed tomography examinations

Abstract

Advances in diagnostic medical imaging in the past few decades using procedures such as computed tomography (CT), have significantly enhanced health care delivery. The effective doses and associated cancer incidence and mortality risks were estimated for adult patients undergoing the five most common types of CT examinations, namely, head, neck, chest, abdomen and pelvis, at Sweden Ghana Medical Centre (SGMC) in Accra, Ghana. The two methods employed in the study were patients’ data collection and phantom measurements to verify the patien-ts’ data. The effective doses were estimated using the dose length product (DLP) from the control console of the CT machine and the anatomic region specific conversion factors. The lifetime attributable risks of cancer inciden-ce and cancer mortality for each patient for a particular examination were both determined from the effective dose, age and sex of each patient using the standard Biological Effects of Ionizing Radiation (BEIR) VII criteria. The effective doses were all within the range of 1 - 10 mSv recommended for CT examinations. The average risk for all the examinations was observed to be very low, i.e. 1 in 10001 to 1 in 10 000. The average lifetime attributable risk (LAR) of cancer incidence was 0.049 % (1 in 2041), while for risk of cancer mortality, the average was 0.030 % (1 in 3333).

Keywords: Computed tomography, Effective dose, Dose length product, Life attributable risk, Cancer incidence, Cancer mortality