ESTRO course Dose Modelling and Verification 2017

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measurement with an ionisation chamber
fluence perturbation
Challenge: perturbation factors
A: field size (aperture)
zref: reference depth
   
 
 
 
 A
A
A
A
p
ρ
S
z AM
zAM
z AD
A,z D
AS
ref
ref
det
w
air ref ref
ref
ref ref w
ref w
cp ,
,
, 













 
Small fields: relative dosimetry - field size factor, Scp