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ESTRO IMRT course 2015
Dose Calculation in Static and Rotational IMRT
Brussels October 8th, 2015
-57-
Dose calculation issues ‚in practice‘:
Dosimetric effects of the treatment table/setup devices
Reiner et al., DEGRO 2013
measured dose difference
with vs. without table [%]
gantry angle
15MV
6MV,
different
depths in phantom
•
depending on the vendor/model,
treatment tables can have a water-
equivalent thickness of ~1 cm w.r.t
dose absorption
•
depending on beam angle, dose
absorption of several percent
→
should be explicitly considered
for dose calculation, especially for
rotational techniques (VMAT),
where oblique angles through the
table cannot be avoided
•
Methods: Dose calculation with
table/setup devices ‘as in CT’, or
dummy contour with water density
override. MIND: evaluate optimal
method for your TPS/dose
calculation algorithm!
solid water phantom
with ionisation chamber
10x10 cm field,
different beam angles