Room: Exhibit Hall | Forum 3
Purpose: In order to use a microDiamond detector for absorbed dose determination, we experimentally determined the beam quality conversion factor (kQ) of the microDiamond detector using a graphite calorimeter.
Methods: Two microDiamond detectors (PTW TN-60019) were calibrated in a Co-gamma ray and flattened high-energy photon beams by National Metrology Institute of Japan (PSDL in Japan). The microDiamond detectors were also calibrated for un-flattened high-energy photon beam from a CyberKnife at Nagoya university hospital. The absorbed dose to water in un-flattened high-energy photon beam was determined using a compact graphite calorimeter in a water phantom. The kQ of the microDiamond detectors were determined as a ratio of the calibration coefficients for the Co-60 gamma ray and the high-energy photon beams.
Results: The experimental results of kQ of the microDiamond detectors was 0.9847Â±0.0055 (k=1) at the TPR20,10 range from 0.64 to 0.76. The present results were observed to constant for the flattened and un-flattened high-energy photon beams. The present results were in good agreement with the Costeâ€™s calculation results.
Conclusion: The kQ of two microDiamond detectors was experimentally determined in the flattened and un-flattened high-energy photon beams. The beam quality dependence of the microDiamond detectors is smaller than a relative standard uncertainty of present kQ (0.6 %) within the TPR20,10 range from 0.64 to 0.76.