paediatrics Brussels 17

UMBRELLA Protocol – RT Target Volume Definition

• ITV: based on the observations of clip motion with 4D-CT-imaging • PTV: includes ITV with 5-10 mm margin to account for movement and set-up variability • PTV margin depends on IGRT frequency and immobilization. Daily online position verification is recommended if kV imaging techniques are available. In this case CTV to PTV expansion may be reduced to 5 mm