Room: Exhibit Hall
Purpose: A prior characterization of Optically Stimulated Luminescent Dosimeters (OSLDs) in a simulated fluoroscopy beam only assessed angular response in-air and at the center of a cylindrical CTDI head phantom. Considering the goal to assess radiation dose to the skin and lens of the eye, OSLDs angled on the surface of a patientâ€™s skin must be assessed as to whether they need an angular correction factor, based on the different geometry and scatter conditions.
Methods: OSLDs were placed in strips of two rows perpendicular to the simulated fluoroscopy beam anode-cathode axis. The strips were placed at ten degree intervals with respect to the plane perpendicular to the x-ray beam direction on the surface of a cylindrical CTDI head phantom. A 0.6cc ion chamber was placed next to the strips in the radiation field for a reference measurement. Three sets of strips and the ion chamber were exposed to an 80 kVp beam, 630 mA, and 1000 ms x-ray beam.The OSLDs were geometrically corrected back to the distance of the ion chamber from the focal spot.
Results: OSLDs after being corrected for beam quality yielded correction factors ranging from 0.87-1.32 (Ïƒ=Â±0.13). The maximum correction factor comes when the OSLDs are at 90 degrees with respect to the beam. The minimum correction factor is where the OSLD is perpendicular to the beam (0 degrees).
Conclusion: Angularity correction factors were generated for use of OSLDs in interventional fluoroscopy rooms for the purpose of placing on patient skin for skin and lens of the eye dose measurements in-vivo.