MRI systems and receive coil arrangements

An MRI system receive coil arrangement 3 comprises: at least one primary receive coil 6 having a first impedance at a predetermined frequency and a first size defined by a cross-sectional area bounded by the primary receive coil; and at least one auxiliary receive coil 7 having a second impedance at said predetermined frequency and a second size 10 defined by a cross-sectional area bounded by the auxiliary receive coil, wherein the first impedance is lower than the second impedance and the first size is larger than the second size. The coil arrangement may be a head, neck, face or shoulder coil. There may be a zone free from electronic components in the coil arrangement so that a radiation therapy or imaging beam may pass through the coil. The coil may be used in a combined MRI and linear accelerator (LINAC) machine or in a combined positron emission tomography and MRI (PET-MRI) machine.