PowerPoint-presentatie

518 / 1228

2. inhomogeneities Medium can be of varying material
(different elemental composition
d Z ff) an e
This affects cross sections
and hence Bθ bθ
, 1 ) , 1 exp(
2
1
1
)( 1
1
) ,(
) ,( 1h sc en r sc
dr R sc
sc dR
dV R sc
r
r sc  
    
 

 
,
, 1 ) , 1 exp(
2
1
) 1(
)( 1
sc en r sc
dr en
sc dR
 
 

 
 
 Can’t we scale the kernel?
Yes and different approaches have
2
) exp(
r
rb B  



appeared in the literature.
 


 , 1
1
) 1(
)( 1
sc en d en
sc dR B



ACE scales attenuation and absorption
voxel-wise according to:
m
 
 


, 1 sc b  sc b
w
sc
w
m bmb
1
, 1 


 


  







sc b
m
sc en
w
m BmB 1
, 1 


 


  









w