L0_2016_Athens_Physics_Programme

IMRT – the tongue and groove effects

• For one intensity-modulated treatment field, the

maximum tongue-and-groove effect could be up to

10%.

• For an IMRT treatment with multiple gantry angles,

the tongue-and-groove effect 1-2 % for typical clinical

cases.

• Tongue and groove effects can be minimised by

applying collimator twists on the beams.

J Deng et al. Phys. Med.

Biol. 46

1039–1060, 2001.