Room: Exhibit Hall | Forum 4
Purpose: To investigate and verify the temperature dependence and performance of a commercial plastic scintillation dosimeter (PSD) system in clinical photon and electron beams.
Methods: Measurements were performed using the commercial OARtracÂ® dose monitoring system and corresponding software (AngioDynamics Inc.). The software uses the user-input temperature of the PSD sensor at the time of measurement and an internal thermal compensation algorithm to correct for the thermal dependence of the PSD. Six PSD sensors were calibrated in both a 6 MV and 12 MeV beam by the University of Wisconsin Radiation Calibration Laboratory. The PSD sensors were then placed in a custom-made immobilization holder and submerged in a beaker of water and irradiated with 6 MV and 12 MeV beams. The temperature was held within 0.1Â°C of the user-entered temperature in the OARtracÂ® software during each measurement using a combination of water and a hot plate, with temperatures ranging from 16-40Â°C. The software does not allow for input of temperatures below 16Â°C, and temperatures above 40Â°C are not clinically relevant as body temperature is near 37Â°C. The dose reading output by the software was recorded and this process was repeated over the entire temperature range.
Results: The deviation from the dose at room temperature was within 2% for measurements with the 6 MV beam and within 1.5% for the 12 MeV beam for the entire temperature range of 16-40Â°C. The difference between the relative electron and photon PSD response for temperatures from 16-32.5Â°C was within 0.55%, however, the difference above 32.5Â°C increased to 1.3% at 40Â°C.
Conclusion: The measured dose reading from the OARtracÂ® PSD system varies by less than 2% for photon measurements and 1.5% for electron measurements over a temperature range of 16-40Â°C for 6 MV and 12 MeV clinical beams.
Funding Support, Disclosures, and Conflict of Interest: Clint Zeringue is a paid consultant for AngioDynamics Inc., Manufacturer of the OARtrac system.