Flipping Book - IMRT

450 / 1544

Region Homogenous,
simple
geometry
Complex geometry
More complex
geometries
δ1 Central beam axis data
– high dose, low dose
gradient
2% 3% 4%
δ2* Build-up region of
central axis beam,
penumbra region of the
profiles - high dose,
high dose gradient
2 mm
or
10%
3 mm
or
15%
3 mm
or
15%
δ3 Outside central beam
axis region - high dose,
low dose gradient
3% 3% 4%
δ4** Outside beam edges –
low dose, low dose
gradient
3%-3mm
RW50
***
Radiological width –
high dose, high dose
gradient.
2 mm or 1% 2 mm or 1% 2 mm or 1%
δ50-90 Beam fringe – high
dose, high dose
gradient
2 mm 3 mm 3 mm
ESTRO Booklets on QA for NON-IMRT beams
4%-4mm 5%-5mm