Particle Therapy 2017

Effect of oxygen in sensitizing cells to radiation

+ O2 to „stabilize“ damage R º + O2 RO2 º

hypoxic

S u r vi vi n g fr a

indirect effects

normoxic

Gray et al. 1953

c ti o n

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 .