Physics Athens 2016

IMRT – the tongue and groove effects

Nominal leaf edges

Attenuation in Tungsten, 2 MeV photons

(monoenergetic)

I/I 0 [%]

Depth [cm] ! " ! # = % &'.')).*+ ,- ./ - 0 *.1) 0 ./ 2 4 56 = 0.8427 ! < ! # = % &'.')).*+ ,- ./ - 0 *.1) 0 ./ 2 ' 56 = 0.7102 100 − ? @ ? + + ? B ? + = 0.8675 < ? + = 1 Loss by tongue+Gain by groove

I G

I L

I T

I 0

“Only primary component of radiation accounted for”

03/01/13