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Oliver Jäkel
Medical Physics
Pseudo CTs based on daily MRI and reference CT
Offline MR-gudidance
fxMRI
m
2
fxCT
art
3
rMRI
m
1
rCT
m
5 6
RT‐planning
fraction i
time
RT‐dose
on rCT
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
K. Kraus et al.
Phys. Med. Biol.
2017
RT‐dose
on
fxCT
art
4
Page 24
Oliver Jäkel
Medical Physics
Dose accumulation in the patient
•
Simultaeous integrated boost (SIB) IMRT
•
Accumulation of Dose on fxCT
art
in 25 Fx
*
Small deviation from nominal total dose
Dose on rCT
Dose on fxCT
art
Deviations at the PTV border
K. Kraus et al. Phys. Med. Biol. 2017
Nominal (static) dose vs.
accumulated fractions doses
Offline MRI would be a good starting point