Open MRI superconductive magnet with cryogenic-fluid cooling

摘要

An open magnetic resonance imaging (MRI) magnet having first and second spaced-apart superconductive coil assemblies each including a toroidal-shaped coil housing containing a superconductive main coil in thermal contact with a cryogenic fluid contained in a dewar. Preferably, each main coil is located outside of and in solid-conduction thermal contact with its corresponding dewar (instead of inside the dewar). Preferably, a surrounding single (not double) thermal shield is cooled by liquid cryogen boil-off or by a cryocooler coldhead. All this allows the main coil to be located closer to the magnet's open space which reduces magnet cost by reducing the amount of coil needed for the same-strength magnetic field.