Radiation dosimetry of the FluoroCAT scan for real-time endoscopic sinus surgery

OBJECTIVE/HYPOTHESIS: The FluoroCAT platform of the GE InstaTrak 3500 Plus reconstructs images acquired from the GE OEC 9800 Plus fluoroscope into triplanar images which allow the surgeon to perform real-time endoscopic sinus and skull-base surgery. The radiation dosimetry for the new scanning protocol required by the FluoroCAT has not been reported. This study was designed to measure the radiation dose of a FluoroCAT scan and compare this to the dosimetry of an InstaTrak CT scan. STUDY DESIGN: Prospective study. METHODS: A standardized CT head phantom was used along with a CT ion chamber to measure radiation exposure. FluoroCAT scans were performed using the GE OEC 9800 Plus fluoroscope. Scans were performed using each of the three fluoroscopic scanning modes on the GE OEC 9800 Plus; normal fluoro, high-level fluoro, and Digital Cine at 15 pulses per second (pps). RESULTS: The highest radiation dose was measured using Digital Cine 15 pps. The dose measured at the center of the head phantom was 4.1 Gy while the maximum surface dose was 10.7 mGy. The center and surface radiation dose recorded from the CTDIvol reading on the control panel of a GE Lightspeed Plus during an InstaTrak CT scan was 85 mGy. CONCLUSIONS: Using the GE OEC 9800 Plus fluoroscope to accumulate images for the FluoroCAT platform in the InstaTrak 3500 Plus resulted in less radiation compared to an InstaTrak CT scan. This will allow multiple scans to be performed intraoperatively, giving the surgeon the opportunity to perform real-time endoscopic sinus and skull-base surgery. EBM rating: C-4 (C) 2006 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.