Medical apparatus

An rf coil of an MRI apparatus can be lowered or raised, on one or more flexible lines, but is constrained to move in only one direction. A constraining mechanism 118 is coupled between the bore structure and the rf coil device 116, allowing movement of the receiving coil device in a single linear dimension, vertical, and one or more retractable suspension mounts, each comprising a flexible line 120, or wire, is arranged to suspend at least part of the receiving coil device within the bore. The constraining device may retract and may have a scissors mechanism (fig 3) which may allow intersecting arms to be rotatably coupled at an intersection point. Winches may be connected to one or more wires for extension or retraction of the flexible wires preferably controlled by a computer. The MRI equipment may be used with therapeutic radiation (fig 1, 110). Preferably, the radiofrequency coil device comprises control circuitry 126 which may be located at one or more of ends so the receiving coil may lie outside the radiation volume which may be for protection purposes.