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ESTRO IMRT course 2015
Dose Calculation in Static and Rotational IMRT
Brussels October 8th, 2015
-58-
Dose calculation issues ‚in practice‘:
Dose calculation in presence of CT artifacts
•
typical cases in RT: dental
metal implants, hip implants
•
significant dose calculation
errors possible in soft tissue
artifact regions due to wrong
Hounsfield (CT-) values
•
Hounsfield values of metal
structures itself wrong as well
AND usually dose calculation
algorithms do not model
radiation transport through
metal correctly
→
do not trust your dose ‘behind’
metal structures!
→
if possible (hip implants), try
to avoid beam directions passing
metal structures
further reading e.g. Kim et al. 2006 (Radiother. Oncol. 79(2))
pragmatic approach in
our department:
dummy contours,
density override with
water density