Advanced Physics for Brachytherapy 2018

The method …

• Let us start again from the simplest case (point isotopic monoenergetic photon source in infinite medium of given composition) • at any point I know more than D prim :

i

r

R =Ψ R

→

exp(

−



)ir

i

2 ir 4π

i ρ μ (=T Ψ)

i

i ρ enμ (=K D : CPE = i Τ) μ enμ ( Ψ)

under



i i prim

μ ( Τ)

enμ-μ

μ enμ

-Τ=S =

( K

=

- (1 Ψ)

)1 − =

i

i

i

i

i

i primD

ρ

μ

en

• If I know the spectrum of the source I know the amount of energy per unit mass scattered in first interactions of primary photons, S 1sc