The establishment of local diagnostic reference levels for computed tomography cerebral angiography in Jeddah city of Saudi Arabia

Abstract Purpose Cerebral computed tomography angiography (CTA) is a useful imaging modality for the diagnosis of blood vessels in brain diseases. The aim of this study was to assess the radiation dose and risk estimation for cerebral CTA scans for adult patients and introduce local diagnostic reference levels (LDRLs) for cerebral CTA patients. Methods In this retrospective study, 291 patients (194 male and 97 female) underwent cerebral CTA scans of the head. The dosimetric quantities of the CT dose index volume (CTDI vol ) and the dose length product (DLP) were collected. Following this, the effective dose, cancer risk and genetic risks were calculated. CTDI vol and DLP were derived; the suggested LDRLs were determined based on the 75th percentile for all examinations. Results The mean patient dose values for CTDI vol , DLP and effective dose were 42.83 ± 1.98 mGy, 1691.76 ± 128 mGy·cm and 5.20 ± 0.39 mSv, respectively. The CTDI vol value was the same for both sexes, while the DLP and effective dose values for males were 4% higher than for females. The cancer risk value for cerebral CTA was 29 × 10 −5 ± 3.2 Sv −1 , and the genetic risk was 10 × 10 −4 ± 1.2 Sv –1 . The LDRL value for CTDI vol was 32.36 (mGy) and for DLP was 1266.25 (mGy.cm). Conclusion This study assessed the radiation doses for cerebral CTA scans and introduced local DRLs for cerebral CTA examinations. In this study, the DLP and effective dose values were higher than those of other studies. The procedure of cerebral CTA scans that include total head and neck area should be optimized in regard to scan length and the head and neck k -factor. Therefore, it is highly recommended to establishing regional and national DRLs.