Advanced Physics for Brachytherapy 2018

2. inhomogeneities

Medium can be of varying density What changes…?

Our basic equation already accounts for: • Density @ scatter release voxel • Density @ energy absorption voxel

iρ

= 1scD j

1sc,i S

dVjh

 V

ρ

j



1 )( 1

r





) ,(

sc dR

r sc 

) ,( 1h =

=

exp(

−



) , 1 



The kernel also changes …!

sc

, 1 sc en r 

2

dV R sc

1 R sc

dr 

1



1 )( 1

sc dR

=

exp(

−



) , 1 



sc

, 1 sc en r 



2

dr en 

1(

−

)



B

) rb

exp(

−





=

2

r



1 )( 1

sc dR

B

=





 , 1 sc en d en





1(

−

)



b

=



sc



 , 1