513 / 1228
Input:
1. I need to be efficient
•
D
prim
distr.
•
Source primary spectrum for calculating
S
An efficient algorithm for the
calculation of dose from 1
st
scatter:
1sc
•
1
st
scatter kernel
•
Individual voxel density data
•
Calculate S
1sc
distr., from D
prim
distr.
•
Choose ΔΩ: optimal number of
Assumptions:
CC:
•
S does not vary with θ within ΔΩ (Bθ
directions
•
Construct lattice of transport lines (B
θ
,
b
θ
per ΔΩ, relative to direction of
1sc
,
bθ constant along transport line)
•
S
1sc
generated, emitted and absorbed
along transport line
primaries)
•
Ray-trace along each transport line for
Δr
i
and iteratively calculate D
i
and:
•
S
1sc
generated per unit r is constant
•
Sum D
i
from all transport lines
within the same voxel (scerma does not
vary considerably within voxels)
)]
exp(
1[
1
1
ir b
i
i
B
)]} iΔr
exp(
1[ iΔr {
iΔr iρ
)
1
exp( }
1
)]1
exp(
1[
2 1- 1sc,i
S1-iρ{
1scD 1 1scD 1scD
b
b B
ir b
ir b
b
i i
i
i
i
i
iΔr
2
1sc,i
S
b