ESTRO PT 2018

Effect of oxygen in sensitizing cells to radiation

+ O

2 to „stabilize“ damage R º + O 2 RO 2 º

hypoxic

indirect effects

normoxic

Surviving fraction

Gray et al. 1953

Dose OER = the ratio of dose in the absence of oxygen to dose in the presence of oxygen needed to produce the same biological effect.

direct effects

mammalian cells, ratio is usually 2.5 – 3.0 .