Establishment of an institutional diagnostic reference level for vascular lower extremity computed tomography angiography

Abstract

About 70% of all collective doses from medical tests come from computed tomography (CT), the primary public radiation exposure source. Patients received higher doses during contrast-enhanced CT procedures (Angiography) than routine CT procedures. The current research aims to quantify the patients' radiation doses, estimate the cancer risk probability, and establish institutional diagnostic reference level (IDRL) during lower extremity angiography. One hundred eleven patients (61.3% male and 38.7% female) underwent contrast-enhanced CT procedures. A 160-Slice CT scanner was used for image acquisition for all patient populations. IDRL values were quantified based on the 3rd quartile value of the CT dose descriptors. All procedures were carried out at Al-Moaallim Medical City, Khartoum, Sudan. A computer software (CT-Expo, ImPACT) was used to extrapolate the effective dosage per extremity CTA examination was estimated. The mean patient age (years) was 56.1 ± 18 (18–82). The patient’s radiation doses was quantified using volume CTDI and dose length product (DLP) to 7.3 ± 2 (2.9–16.8) (mGy) and 3712 ± 126 (279–8374) (mGy.cm), respectively. The average effective doses were 22 mSv (range: 1.7–50) per lower CT angiography for the lower extremity. The proposed IDRL for the VCTA procedure was 3562 mGy cm and 17 mGy for DLP and CTDIvol, respectively. The proposed IDRL is higher than the previously published studies; therefore, patient dose optimization is recommended.