{"entity":{"id":"oxygen-enhancement-ratio","kind":"term","name":"Oxygen enhancement ratio","aka":[],"tldr":"How many times more radiation a cell without oxygen needs to be killed compared with the same cell with oxygen: about 2.5 to 3 for X-rays, close to 1 for the heaviest particle beams.","summary":"Oxygen reacts with the free radicals radiation creates in DNA and makes the damage permanent, so oxygenated cells die at lower doses. The oxygen enhancement ratio is near 3 for photons and protons and falls toward 1 for high-LET radiation such as carbon ions and neutrons, which is one argument for particle therapy in hypoxic tumours and for boron neutron capture therapy.","asOf":"2026-09-16","wikipedia":"https://en.wikipedia.org/wiki/Oxygen_enhancement_ratio","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Oxygen_enhancement_ratio"}],"tags":["radiation-wave1"],"related":[],"cancers":[],"sections":[],"technologies":["tumour-hypoxia-modification","carbon-ion","bnct"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"notes":[],"category":"Biology basics"},"route":"/terms/oxygen-enhancement-ratio/","neighbours":{"technology":[{"id":"bnct","kind":"technology","name":"Boron neutron capture therapy","route":"/technologies/bnct/"},{"id":"carbon-ion","kind":"technology","name":"Carbon-ion therapy","route":"/technologies/carbon-ion/"},{"id":"tumour-hypoxia-modification","kind":"technology","name":"Tumour hypoxia: imaging and modification","route":"/technologies/tumour-hypoxia-modification/"}]}}