Dialysis system with radio frequency device within a magnet assembly for medical fluid sensing and concentration determination

A dialysis system comprising:

• a magnet assembly that generates a magnetic field, the magnet assembly defining an opening;
• a radio frequency device disposed in the opening of the magnet assembly, the radio frequency device defining a first cavity configured to receive a first section of a first portion of a cartridge, the first cavity being internal to the radio frequency device, and a second cavity being defined between the radio frequency device and the magnet assembly such that the second cavity is outside of the radio frequency device, the second cavity being configured to receive a second section of the first portion of the cartridge;
• and
• a dialysis fluid pump that is operable to pump dialysis fluid to the first portion of the cartridge when the first section of the first portion of the cartridge is disposed in the first cavity and the second section of the first portion of the cartridge is disposed in the second cavity,
• wherein the radio frequency device is operable to receive radio frequency energy generated by excited atoms in the dialysis fluid in the first portion of the cartridge when the first and second sections of the first portion of the cartridge are disposed in the first and second cavities, respectively, and dialysis fluid has been pumped to the first portion of the cartridge.