The disclosure relates to a system for immobilizing and supporting a subject in a medical procedure. The system may include a treatment apparatus configured to generate a radiation beam, and a device for immobilizing a subject. The device may include an immobilizing component for immobilizing at least one portion of the subject, and a radio frequency (RF) coil configured to receive a magnetic resonance (MR) signal related to the at least one portion of the subject. The immobilizing component may be configured to switch between a first mode and a second mode. The first mode may correspond to a positive pressure or a constant pressure related to the device. The second mode may correspond to a space of vacuum or substantially of vacuum related to the device. The RF coil may be located in the immobilizing component according to a position where the radiation beam is incident on the device.