Research Masterclass in Radiotherapy Physics 2017

Pseudo CTs based on daily MRI and reference CT Offline MR-gudidance

1

RT‐dose  on rCT

rCT m

rMRI m

RT‐planning

2

3

fxMRI m

fraction  i

fxCT art

time

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RT‐dose  on  fxCT art 4

K. Kraus et al.  Phys. Med. Biol.  2017

1. Rigid Registration of reference images rCT & rMRI 2. Elastic registration of fraction MRIs 3. Transform rCT according to transformation 2 4. Recalculate dose on artificial fraction CT fxCT art 5. Transform dose back to reference rCT  6.   Sum up fraction doses

Oliver Jäkel

Medical Physics

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Dose accumulation in the patient

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• Simultaeous integrated boost (SIB) IMRT  • Accumulation of Dose on fxCT art in 25 Fx

Small deviation from nominal total dose 

Nominal (static) dose vs.  accumulated fractions doses

Deviations at the PTV border 

K. Kraus et al. Phys. Med. Biol. 2017

Dose on rCT 

Dose on fxCT art

Oliver Jäkel Medical Physics Offline MRI would be a good starting point

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