Traceability of absorbed dose to water in high-energy photon beams in medical electron accelerators

Results obtained by direct measurement of absorbed dose to water for medical electron accelerators were compared with that by indirect measurements (through converting the measured air kerma into absorbed dose to water). Experiments results demonstrate that the difference between two methods is within 1%, it is validated by the transfer comparison method meanwhile. It is demonstrated that the absorbed dose to water traceability system based on the photon absorbed dose to water for the accelerator is feasible. This provides the basis for direct measurement of absorbed dose to water for accelerators. (authors)