Dose 2016

Kerma, collision kerma Kerma is the expectation value of the energy transferred by photons to the medium per unit mass d K = V

ε

[ ] Gy

tr

dm

Monoenergetic photon beam

  

 

  

  

µ

µ

Φ=

Ψ=

tr E K

tr

ρ

ρ

Collision Kerma: energy transferred to charged particles K includes all energy transferred to collision and radiation losses

K K K + =

col

rad

(

) g K K

1

− =

col

  

  

µ

en

ρ

  

  

µ

=

Ψ=

en

K K

col

ρ

  

  

µ

tr

ρ