Assessment of radiation-induced cancer risk to patients undergoing computed tomography angiography scans

Background: Computed tomography angiography (CTA) scan is a suitable imaging technique to evaluate the blood vessels. However, one major disadvantage is the potential risk of cancer related to ionizing radiation exposure during the procedures. The aim of this investigation was to estimate the risk of exposure induced cancer death (REID) values for some common computed tomography angiography (CTA) scans. Materials and Methods: The scan parameters and patient gender and age were collected for a total of 251 patients undergoing CTA scans of the head (51), carotid (50), abdomen (50), thoracic (50) and the lower extremities (50). The effective diameter, scan length, effective tube current and the dose-length product (DLP) values were obtained for each patient. The organ doses and the effective dose were calculated by the ImpactDose program. The REID values were estimated for the different CTA scans by the calculated organ doses and corresponding age- and sex- specific risk factors.  Results: The REID values for the CTA scans of head were 17±4 and 20±3 per million, carotid were 35±9 and 67±14 per million, the lower extremities were 60±26 and 64±24 per million, thoracic were 97±28 and 204±72 per million, and for abdomen were 101±25 and 194±72 per million, for males and females, respectively. Conclusion: The results of this investigation showed that CTA scans are associated with non-negligible risk of exposure induced cancer. A variation in radiation cancer risk as a function of age and gender of the patients was demonstrated and found that the younger female patients were at the highest risk.