Determination of geometric information and radiation field overlaps on the skin in percutaneous coronary interventions with computer‐aided design‐based X‐ray beam modeling

PURPOSE: This study aimed to develop a method for the determination of the source‐to‐surface distance (SSD), the X‐ray beam area in a plane perpendicular to the beam axis at the entrance skin surface (A(p) ), and the X‐ray beam area on the actual skin surface (A(s) ) during percutaneous coronary intervention (PCI). MATERIALS AND METHODS: Male and female anthropomorphic phantoms were scanned on a computed tomography scanner, and the data were transferred to a commercially available computer‐aided design (CAD) software. A cardiovascular angiography system with a 200 × 200 mm flat‐panel detector with a field‐of‐view of 175 × 175 mm was modeled with the CAD software. Both phantoms were independently placed on 40 mm thick pads, and the examination tabletop at the patient entrance reference point. Upon panning, the heart center was aligned to the central beam axis. The SSD, A(p) , and A(s) were determined with the measurement tool and Boolean intersection operations at 10 gantry angulations. RESULTS: The means and standard deviations of the SSD, A(p) , and A(s) for the male and female phantoms were 573 ± 15 and 580 ± 15 mm, 8799 ± 1009 and 9661 ± 1152 mm(2), 10495 ± 602 and 11913 ± 600 mm(2), respectively. The number of A(s) overlaps for the male and female phantoms were 15/45 and 21/45 view combinations, respectively. CONCLUSIONS: CAD‐based X‐ray beam modeling is useful for the determination of the SSD, A(p) , and A(s) . Furthermore, the knowledge of the A(s) distribution helps to reduce the A(s) overlap in PCI.