A whole-body MRI scanner can keep its superconducting magnet cold with less than a liter of liquid helium. Siemens Healthineers described that design when its Magnetom Free.Max received U.S. clearance in July 2021.
The interesting change sits behind the scanner rather than on its screen. Conventional systems can require several hundred liters of helium and a dedicated exhaust pipe. Free.Max uses a sealed magnet with 0.7 liters, according to the company's DryCool specifications.
Helium keeps the magnet at the extremely low temperature needed for superconductivity, when electrical resistance disappears. Reducing the cooling system changes where a hospital can physically install the machine.
Siemens says this design needs no quench pipe, the specialized route used to vent helium during a rapid loss of superconductivity. That removes one building requirement. The company also described a system weighing less than 3.5 tons in its clearance announcement.
The trade-off involves the imaging hardware. Free.Max operates at 0.55 tesla, a measure of magnetic field strength. Its Deep Resolve software reduces noise and uses deep learning during image reconstruction.
Those image-quality statements come from the manufacturer. The clearance announcement does not establish that a lower-field scanner replaces every higher-field system or every examination.
The story is therefore about engineering access: the magnet, cooling equipment, building and reconstruction software work as one system. A smaller helium supply changes the room as well as the scanner.
