oxygen enhancement ratio
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oxygen enhancement ratio (OER),
a measure of tumor sensitivity to the presence or absence of oxygen, expressed as the ratio of radiation dose required to produce a given effect with no oxygen present to the dose required to produce the same effect in 1 atmosphere of air.
ox·y·gen en·hance·ment ra·ti·o(OER) (ok'si-jĕn en-hans'mĕnt rā'shē-ō)
Ratio of the dose of radiation necessary to produce a given biologic response in the absence of oxygen to the dose required to achieve the same response in the presence of oxygen.