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IGRT: ‘Simple’ Practice
‘Gradual’ changes in anatomy & shape
Changes over weeks eg weight loss in H&N patients
Adapt XRT plans
E.g. Adapt treatment to shrinking parotid gland/tumor
‘Daily’ changes eg organ filling or emptying
Eg bladder and rectum causing displacement or
deformation, head and neck flexibility
Radiotherapy
Adjust treatment position ± adaptation
Use surrogates of target position or direct organ/target
visualisation
‘Fast’ changes or rapid moving targets
Eg lung XRT with respiration
Prevent base line shift (gradual), Track or gate XRT or
freeze the ‘motion’