IMRT

O-ring stability

è “ visual ” inspection of star shot film è Quality indicated by multi-axial symmetry of the star pattern l Radiosensitive film placed in plane of rotations l Sequence of narrow fields at different angles l Intersection of these fields forms a star-shaped pattern

Central “ Star ” pattern

Depuydt et al. 2012 (Phys. Med. Biol. 57 (2012) 2997–3011)

8