IMRT 2018

adapted from Woo and Cunningham 1990 (Med. Phys. 17(2))

Kernel-based methods: Rectilinear density rescaling of the kernel



) sr 





 

r



)(

(

(

) ) () ,( , s r − 

water

2

, Eh

sr E h sr 

,

=





) ,( 

s

rel

rel



water

‘Rectilinear’ rescaling with the mean relative density along the path between s and r:

this would be the kernel dose in a homogeneous medium: h water !



s 

( )  s

) sr 



1



(

 sd



,

=

  s r  

rel

−



water

r

…and after rectilinear rescaling

→ The point kernel dose is dependent on location inside of inhomogeneous media (patient!) → efficient numerical dose calculation w. fast fourier transform not possible without further approximations

r

ESTRO IMRT course 2017 Dose Calculation in Static and Rotational IMRT Madrid April 13th, 2017

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