Radiation Dose Reduction in MDCT through Tube Current Optimization of Pre-Contrast Media on CT Brain Angiography Subtraction Technique

Background/Objectives: The purpose of this study was to reduce of radiation dose through optimizing the tube current exposed pre-contrast media in multi-detector computed tomography (MDCT) brain angiography subtraction technique (BAST). Methods/Statistical Analysis: The tube voltage were fixed and the tube current was set to 100 vs 70 mAs, 100 vs 50 mAs and 100 vs 30 mAs for the two respective inspections performed pre-contrast media. The average diameters of the posterior cerebral artery, the anterior cerebral artery and the basilar artery were measured to verify the statistical difference on 30 patients. In addition, the radiation dose in the tube current is measured. Findings: When the tube current was set adjusted from 100 mAs to 30 mAs, the average diameters of the left/right posterior cerebral artery, the left/right anterior cerebral artery and the basilar artery indicated no significant difference. And the result of measured weighted CTDI values are 8.9 mGy in 100 mAs, 6.24 mGy in 70 mAs, 4.71 mGy in 50 mAs, 2.63 mGy in 30 mAs and could be reduced up to 70.5%. This study is limited in that it was conducted based on a small experimental group to minimize the number of people being exposed to radiation. However, as a result of continuously applying the experiment results to the current clinical environment, there has been no request for a re-inspection due to the low radiation dose. Improvements/Applications: The use of subtraction technique is expected to decrease the exposure dose while operating CT brain angiography on patients and actualize the safe CT brain angiography