In contrast, many primary standards laboratories are developing standards of absorbed dose to water. These are based on different approaches and thus a much more robust system is being put in place. The solutions to these problems will be discussed because they have broader implications. Once a high energy absorbed dose calibration service is established, the question is how to use it most effectively. Since it is much more expensive to calibrate chambers in accelerator beams than in beams, and because the vast majority of dosimetry standards laboratories do not have linear accelerators, any dosimetry protocol based on absorbed dose calibration factors should be based on calibrations in a beam.
Clinical dosimetry based on such a system is much simpler than that based on air kerma calibrations.