Hypoxia is both a consequence and adriver of malignant progression and leads to a poor therapeutic response toradiotherapy . The biological effectiveness of radiotherapy highly depends onfree radicals from oxygen to effectively destroy the target cells. This is whyhypoxic areas show a signficantly higher radioresistance and require an up tothree times higher dose for the treatment to achieve the same level ofbiological effectiveness as in normally oxygenated tissue (missing citation).Adaptive dose optimisation based on a hypoxic biomarker is most likelybeneficial for both boosting high-risk sub-volumes (missing citation) and maybeeven de-escalating dose in tumour areas with a higher oxygenation (missingcitation).Current studies typically use the PET tracers Fluormisonidazole (FMISO) orCu(II)-diacetyl-bis(N