IMRT

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

pragmatic approach in our department: dummy contours, density override with water density

further reading e.g. Kim et al. 2006 (Radiother. Oncol. 79(2))

ESTRO IMRT course 2015 Dose Calculation in Static and Rotational IMRT Brussels October 8th, 2015

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