Radiobiological studies among different laboratories and centers need standardization of radiation dose. Apart from dosimetry to determine the actual absorbed dose in Gray (Gy), due consideration of differences in biological effect is needed at different energies. Relatively high energies (megavoltage of >500 KeV) are the most relevant to both exposures in clinical RT and from nuclear incidents.
The escalating restrictions and costs of using gamma irradiators as imposed by security requirements have, however, prompted the increasing use of orthovoltage X-ray machines in experimental studies.
Reasonable equivalency for a given biological effect per dose is warranted for X-rays to replace gamma-irradiators.
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