Advanced Physics for Brachytherapy 2018

Equations for the transport of scerma generated at each point along a transport line

1. I need to be efficient

Δr

2

Under the collapsed cone approximation: • Scerma does not vary with θ within ΔΩ (Bθ, bθ constant along transport line) and scerma generated, emitted and absorbed along transport line

1

θ

2

and assuming:

• Scerma generated per unit r is constant within the same voxel (scerma does not vary considerably within voxels)

Dose from voxel 2 points at r’ along Δr2, to a voxel 2 point at r : ρ2 D S exp[ ( ')] ' 1sc2 2 1sc,2 ρ2 ' B b r r d dr r   = − −  =   → 

Δr

2

r’

0≤r’≤r 0

r

r

B

( b r r − − = ')]dr'



S

exp[



1sc,2





0 [1 exp(

2

b r 

− −

)]

B



S1sc,2



b

