Particle Therapy 2017

Reoxygenation

Hypofractionation

Oxygen is an important enhancement factor for radiation effects (very low O2-concentration (<0.5% / 3 mm Hg) T he process of reoxygenation is time, fraction interval and probably fraction size dependent Hypoxic cells in tumors dominate their response to large single doses of r adiation Cell inactivation and/or reduction of hypoxia more prominent after high doses. - highly unlikely that reoxygenation would occur within 2–3 days after hypofractionation Reoxygenation does not completely eliminate hypoxia