A magnetic resonance (MR)-radiotherapy (RT) hybrid system for treating a patient is disclosed. The MR-RT hybrid system comprises: an MR imaging (MRI) apparatus comprising bi-planar magnets configured to generate a magnetic field； a radiation source configured to supply a radiation beam to treat the patient； a gantry configured to couple the MR apparatus at a first end and the radiation source so that they can rotate in unison； a treatment support configured to support the patient； a motor configured to move the treatment support； and a controller. The controller comprises a processor and memory having stored thereon instructions, which when executed by the processor, cause the motor to move the treatment support in order to avoid collision between the MRI apparatus and the patient when the MRI apparatus is rotated. A method for positioning the treatment support within the MR-RT hybrid system is also disclosed.
