Basic Clinical Radiobiology 2017

Logistic model of response

" # $

% & '

u = ln P

exp( u ) 1 + exp( u )

P =

1 − P

Dd + ...

u = a

+ a

D + a

0

1

2

With Logistic , the inflection (max slope) occurs at Response = 50% ( P = 0.5, u = 0) P /(1- P ) is called the odds of the response, u is called the logit of P