Dose Course 2018_Flipping book

Handling the beam spectrum – offaxis changes

Effect of spectral changing with lateral position can be modelled by lateral variation of the energy release parameters. The offaxis variation of  P is experimentally accessible, variation of the other raytracing parameters can be correlated to  P , see MedPhys, Vol32, pp1722-37.

( ) ( ) 0 

( ) ( ) 0

  

  

HVL HVL

 

P

=

:



P

Tailor, R.C., et al. Medical Physics, 1998. 25 (5): p. 662-667

Heterogeneities considered by using different sets of parameters for each tissue type, mapped by using tissue lookup tables from the Hounsfield numbers!

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