Characterization of an Interventional Cardiology Bi-Plane Room for Monte Carlo Dosimetry
Abstract
Purpose
Congenital heart defects are the most common type of birth defect, and their management often requires lifelong medical care. Interventional cardiology procedures frequently rely on imaging modalities that use ionizing radiation, potentially exposing pediatric patients to high cumulative doses and increasing the risk of radiation-induced malignancies. The purpose of this study was to characterize a bi-plane interventional cardiology system for use in Monte Carlo-based organ dosimetry of pediatric procedures.
Methods
Measurements were performed on a bi-plane Philips Azurion Clarity IQ system. To accurately reproduce clinical exposures in a Monte Carlo radiation transport code, the half-value layer (HVL), table transmission factor (TTF), and cumulative air kerma (CAK) accuracy were measured. Data were acquired for all available beam qualities for both frontal and lateral tubes; TTF measurements were obtained for the frontal tube only. TTF was measured in RAO/LAO and CRAN/CAUD orientations at 0°, 15°, 30°, and 45° beam angulations. A CIRS ATOMâ 5-year-old phantom was used. High-resolution CT images of the phantom were segmented using Slicer and converted to a polygon mesh for import into the Particle and Heavy Ion Transport Code System (PHITS). A simulated cardiac catheterization procedure was performed with the ATOM phantom outfitted with OSLDs, and measured doses were compared with the Monte Carlo simulation results.
Results
Frontal tube HVLs ranged from 2.07 to 11.8 mm Al, while lateral tube HVLs ranged from 1.98 to 11.8 mm Al. TTF values decreased with increasing beam angulation and ranged from 0.644 to 0.867, with comparable results between LAO/RAO and CRAN/CAUD directions. CAK accuracy ranged from -6.5% to 2.5% for the frontal tube and -3.14% to 7.0% for the lateral tube. Monte Carlo doses were within 10% agreement.
Conclusion
The bi-plane system was successfully characterized. These data will support Monte Carlo-based organ dose estimation for pediatric interventional cardiology procedures.