PHITS-based radiation dose analysis among healthcare workers during coronary angiography procedures in the Philippine setting

Purpose: Coronary angiography (CA) is among the most frequently performed interventional cardiology procedures in the Philippines, where healthcare workers including interventional cardiologists, fellows, nurses, and radiologic technologists face occupational radiation exposure primarily from patient-scattered radiation. This study aimed to estimate and analyze occupational radiation doses to catheterization laboratory staff during routine CA procedures in the Philippine context using Monte Carlo-based simulations, assess compliance with national and international dose limits, and identify opportunities for optimization. Methods: The Particle and Heavy Ion Transport Code System (PHITS) was used to model a generic cardiac catheterization suite comprising an x-ray tube, patient phantom, and staff positions derived from local clinical practices using standard projections. Simulations incorporated realistic beam parameters (i.e., tube voltage, tube loading, and filtration) and available radiation protective measures. Personal dose equivalent, Hp(10), was calculated for the interventional cardiologist, fellow, nurse, and radiologic technologist over typical procedural workloads. Results: PHITS simulations estimated occupational radiation doses across nine coronary angiography projections. The cardiologist received the highest cumulative dose at 5.12 µSv per procedure. The fellow, radiation technologist, and nurse received substantially lower doses of 0.258 µSv, 0.0471 µSv, and 0.064 µSv, respectively, consistent with their greater distance from the primary scatter field. The AP/AP and LAO10/CRAN30 projections produced the highest cardiologist doses, while RAO15/CRAN45 yielded the lowest, consistent with published literature. The simulated value agreed closely with the local benchmark of 4.63 µSv reported from a previously conducted study, confirming the credibility of the computational model. Conclusion: PHITS-based computational modeling offers a structured, reproducible approach to estimating occupational radiation exposure in interventional cardiology settings, with further potential to characterize doses to the lens of the eye and extremities. As these methods mature, researchers and medical physicists can deploy them to drive evidence-based optimization of radiation protection protocols and foster a culture of safety across Philippine interventional cardiology departments.