761 / 1542
•
Tomotherapy has greater flexibility of shaping dose in axial slices than
both standard IMRT and VMAT: full IMRT per beam direction,
and beams can come from all co-planar directions
•
Tomotherapy may in longitudinal direction be more restricted because of field
width, if w=1cm
→
longer treatment times
•
Tomotherapy and VMAT have larger spreading of low doses over large
volumes than standard IMRT
•
In contrast with standard IMRT, Tomotherapy and VMAT do not require
selection of limited number of optimal beam directions
•
For simple cases, VMAT seems substantially faster than standard
IMRT with comparable plan quality for PTV and OAR (but spreading)
•
In complex cases, single-arc VMAT with short treatment times may
compromise quality of the dose distribution.
•
Only standard IMRT allows “free” use of non-coplanar beams
Comparison of competing techniques
Standard IMRT, Tomotherapy, VMAT
Bortfeld and Webb, 2009