The reproduction for the absorbed-dose to water of the clinical accelerator photon beams

Introduction The absorbed-dose to water( D w ) of the clinical accelerator photon beams is a fundamental quantity in radiation oncology. The accuracy of D w has been maintained by the exposure or air kerma standard of 60 Co γ radiation in the past few decades. The rapid development of radiation oncology requires the improvement of dissemination system and calls for an absolute measurement of D w . Purpose Perform the study for the reproduction and determine the value of D w via an absolute measurement method. Materials and methods A water calorimeter is used to conduct the measurement of D w . The related corrections such as the non-uniformity of the photon radiation field, the heat conduction, the heat conduction as well as the heat defect of water are clarified by the experiment. Results The D w of 6 MV, 10 MV photon beams is reproduced and compared to the results from a transfer chamber, which is traced to the absolute measurement result in NRC. The discrepancy is less than 0.7%. Conclusion The value of D w of the 6 MV and 10 MV clinical accelerator photon beams has been successfully reproduced via a water calorimetric method. The present work is a preliminary step to participate in the key comparison of BIPM, which is about the absorbed-dose to water of the clinical accelerator photon beams. Disclosure Authors should disclose any relationship that may bias their presentation. Please enter disclosure information here.