The development of a diagnostic reference level on patient dose for head computed tomographyangiography examinations in Korea.

The primary goal of this study was to analyse the state of patient doses in the field for head computed tomography angiography (HCTA) examinations in the Republic of Korea. All survey data, including CT application and patient dose details, were obtained from the general hospitals registered in the Korean Hospital Association. The systematic analysis of patient dose data would allow target value to be established for the weighted CT dose index (CTDIw), volume-weighted CTDI (CTDIvol) and a dose-length product (DLP), which might be used to set diagnostic reference levels. The survey on patients' dose showed that the 75th percentiles in the distribution of CTDIw, CTDIvol and DLP were 34.09, 26.7 and 1816 mGy for the HCTA examinations, respectively.