Effective Dose Evaluation of Cerebral Angiography Using Kerma Area Product and Development of Effective Dose Conversion Factors

Background/Objectives: Transfemoral cerebral angiography (TFCA) involves significant radiation exposure because of prolonged fluoroscopy and repeated imaging sequences. Because complex dose simulations are often infeasible in routine clinical practice, this study employed PC-based Monte Carlo methods to estimate organ-absorbed and effective doses. The primary objective was to establish Kerma area product (KAP)-based conversion factors to facilitate efficient clinical dose assessment. Methods: We analyzed 30 patients who underwent TFCA. Key parameters, including total KAP, tube voltage, and projection angles, were obtained from DICOM Radiation Dose Structured Reports. Monte Carlo simulations were conducted for anteroposterior, lateral, and cranial planes. The conversion factors were then derived by calculating the ratio of the effective dose to the total KAP. Results: The average KAP was 36.23 ± 6.81 Gy·cm2. Effective doses calculated via Monte Carlo simulation were 1.70 ± 0.35 mSv under International Commission on Radiological Protection (ICRP) 60 and 1.90 ± 0.40 mSv under ICRP 103 standards. The corresponding conversion factors were 0.0468 ± 0.0054 and 0.0525 ± 0.0065 mSv/Gy·cm2 respectively. Notably, the ICRP 103-based factor was 12.2 percent higher than the ICRP 60-based factor, reflecting updated tissue weighting factors in modern dosimetry. Conclusions: This study provides standardized conversion factors that allow rapid and reliable dose estimation without requiring complex simulations. The findings demonstrated substantial radiation absorption in the head and neck regions, providing critical data for routine dose monitoring. These results emphasize the importance of rigorous radiation protection and safety protocols during interventional procedures.