Patient-Specific Radiation Dose and Cancer Risk Estimate in Computed Tomography Pulmonary Angiography Examinations Based on Lung Effective Diameter

Computed Tomography (CT) scan examinations has greater demands especially in CT Pulmonary Angiography (CTPA) owing to the public and radiology personnel worries towards CT radiation exposure and risks. The aim of present study is to evaluate the comprehensive radiation exposure in computed tomography pulmonary angiography (CTPA) and its cancer risk. The records of 100 patients who had undergone CTPA were retrieved. The radiation dose exposure, scanning acquisition protocol as well as patient characteristics were noted. Radiation exposure were presented as Volume Computed Tomography Dose Index (CTDIvol), Size-Specific Dose Estimate (SSDE), Dose-Length Product (DLP), and effective dose (E) and organ dose. Effective cancer risk per million procedure was calculated by referring to the International Commission on Radiological Protection Publication 103. The CTDIvol, SSDE, DLP were comparable within different effective diameter groups. The average effective dose received by a patient was 8.68 mSv. The organ dose and effective cancer risk attained for breast, lung and liver were 17.05 ± 10.40 mGy (194 per one million procedure), 17.55 ± 10.86 mGy (192 per one million procedure) and 15.04 ± 9.75 mGy (53 per one million procedure), respectively. In conclusion, CTDIvol was undervalued and SSDE was more accurate in describing radiation dose exposure. The lungs and breast of subjects with large effective diameter were higher risk of developing cancer as they received the highest exposure. Therefore, extra safety measures should be considered for large-sized patients undergoing CTPA.Purpose: This study evaluates the comprehensive radiation exposure in computed tomography pulmonary angiography (CTPA) and its cancer risk.