IMRT

Kernel-based methods: Rectilinear density rescaling of the kernel

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



)(

) r srEh  = ρ



s r sr   

(

(

) ) () ,( , − ⋅

2

water

, ,

) ,( ⋅

E h sr rel ρ

ρ

⋅

s

rel

ρ

water

‘Rectilinear’ rescaling with the mean relative density along the path between s and r: ( ) ( ) ∫ ′ ′ − = s r water rel s sd s r sr        ρ ρ ρ 1 , → 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

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

…and after rectilinear rescaling

r

ESTRO IMRT course 2015 Dose Calculation in Static and Rotational IMRT Brussels October 8th, 2015

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