The invention relates to an apparatus comprising a hadron therapy device and a magnetic resonance imaging device (MRI). The MRI is an open MRI, for acquiring magnetic resonance data in the MRI imaging volume. The nozzle is fixed and positioned for directing a beam along a beam path substantially along said axis, or substantially perpendicularly to said axis. The apparatus comprises a patient support system adapted for supporting a patient in a non-supine position in said MRI. The invention also relates to methods for adapting a treatment plan to movements of organs resulting from displacement of a patient from a supine position wherein treatment plan imaging was performed to a non-supine position for performing the treatment.
