Dose Course 2018_Flipping book

pencil kernel parameterization:

Monte Carlo PB kernel represented as double exponential over radius, tabulated for depths z. Motivations: lateral attenuation ( a z , b z ) and cylindrical geometry 1/ r factor of the effective particle fluencies.

a r

b r

−

−

A

B

e

e

p

z

z

( ) , r z

z

z

=

+

r

r



primary dose scatter dose

4 parameters required at each depth z for a given photon beam

A Ahnesjö et al (1992) Med Phys 19, 263-273

This is the PK kernel parameterization used in Helax-TMS -> Oncentra -> etc