Effective dose equivalents to patients undergoing cerebral angiography.

PURPOSE To determine values of the effective dose equivalent, HE, for patients undergoing diagnostic cerebral angiography and compare these values with radiation doses received by patients undergoing other diagnostic examinations of the head. METHODS The radiographic techniques for ten patients undergoing cerebral angiography were recorded and used to obtain the product of the entrance skin dose and the x-ray beam cross-sectional area. These measured dose-area product data were converted into effective dose equivalents employing published conversion factors which take into account the part of the patient anatomy irradiated and the radiographic technique factors employed. RESULTS The average patient HE value was 10.6 mSv, with a range of 2.7-23.4 mSv. Fluoroscopy contributed approximately 67% of the total HE, with cut films and digital subtraction angiography contributing 26% and 7%, respectively. CONCLUSIONS The radiation doses (HE) to patients undergoing diagnostic cerebral angiography are comparable to the patient doses in nuclear medicine brain studies where the typical HE is approximately 10 mSv. In CT, the patient dose is approximately 2 mSv, whereas in plain skull x-ray examinations, the patient dose is much lower at approximately 0.15 mSv.