Particle Therapy 2017

produce the same biological effect. mammalian cells, ratio is usually 2.5 – 3.0 .

ti OER = the ratio of dose in the o n

absence of oxygen to dose in the presence of oxygen needed to

Dose

hypoxic

Gray et al. 1953

normoxic

S

u

r

vi

vi

n

g

fr

a

c

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

direct

effects

Effect of oxygen in sensitizing cells to radiation