# US 10,371,775 B2 · Dialysis system with radio frequency device within a magnet assembly for medical fluid sensing and concentration determination > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,775 B2 - Document ID: US10371775B2 - Status: Granted - Kind: B2 - Application number: 15/449,127 - Filed: 2017-03-03 - Published: 2017-06-22 - Granted: 2019-08-06 - Earliest claimed: 2013-03-15 - Assignees: Fresenius Medical Care Holdings, Inc. - Applicants: Fresenius Medical Care Holdings, Inc. - Inventors: Ross Peter Jones; Martin Joseph Crnkovich; Fei Wang; Thomas Irvin Folden; Lynn Jensen; Shashikant Dattatraya Kalaskar - Web page: https://patentgrep.com/patent/US10371775B2 ## CPC - G01R 33/465: applied to biological material, e.g. in vitro testing - A61M 1/154: {with sensing means or components thereof} - A61M 1/1562: {Details of incorporated reservoirs} - A61M 1/16: with membranes - A61M 1/1605: {Physical characteristics of the dialysate fluid} - A61M 1/1619: {Sampled collection of used dialysate, i.e. obviating the need for recovery of whole dialysate quantity for post-dialysis analysis} - A61M 1/267: {used for pumping} - A61M 1/3609: {Physical characteristics of the blood, e.g. haematocrit, urea} - A61M 1/36222: {Details related to the interface between cassette and machine} - A61M 1/36224: {with sensing means or components thereof} - A61M 1/36226: {Constructional details of cassettes, e.g. specific details on material or shape} - G01N 24/08: by using nuclear magnetic resonance (G01N24/12 takes precedence) - G01R 33/1276: {of magnetic particles, e.g. imaging of magnetic nanoparticles (G01R33/1269 takes precedence)} - G16H 20/17: delivered via infusion or injection - G16H 50/20: for computer-aided diagnosis, e.g. based on medical expert systems - A61M 2205/12: with interchangeable cassettes forming partially or totally the fluid circuit - A61M 2205/3317: Electromagnetic, inductive or dielectric measuring means - A61M 2205/3324: PH measuring means - A61M 2205/3331: Pressure; Flow - A61M 2205/50: with microprocessors or computers - A61M 2205/6072: Bar codes - A61M 2205/702: automatically during use - A61M 2230/20: Blood composition characteristics - G01R 33/302: {Miniaturized sample handling arrangements for sampling small quantities, e.g. flow-through microfluidic NMR chips} - G01R 33/34053: {Solenoid coils; Toroidal coils} - G01R 33/383: using permanent magnets - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA ## Abstract This disclosure relates to medical fluid sensors and related systems and methods. In certain aspects, a method includes using a medical fluid pump of a medical fluid pumping machine, such as a hemodialysis machine, to deliver medical fluid to a first portion of a cartridge that is positioned within a magnetic field, exciting atoms in the medical fluid in the first portion of the cartridge by applying radio frequency energy to the medical fluid in the first portion of the cartridge, receiving radio frequency energy generated by the excited atoms in the medical fluid in the first portion of the cartridge, and determining a concentration of a substance in the medical fluid based on the received radio frequency energy generated by the excited atoms in the medical fluid in the first portion of the cartridge. ## Claims ### Claim 1 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. ### Claim 2 (depends on 1) The dialysis system of claim 1, wherein the radio frequency device is further operable to apply radio frequency energy to dialysis fluid in the first portion of the cartridge to excite the atoms in the dialysis fluid in the first portion of the cartridge. ### Claim 3 (depends on 2) The dialysis system of claim 2, wherein the radio frequency device is a radio frequency coil. ### Claim 4 (depends on 1) The dialysis system of claim 1, further comprising a controller in communication with the radio frequency device, the controller being configured to determine a concentration of a substance in the dialysis fluid based on the received radio frequency energy generated by the excited atoms in the dialysis fluid in the first portion of the cartridge. ### Claim 5 (depends on 4) The dialysis system of claim 4, wherein the controller is configured to determine the concentration of the substance in the dialysis fluid as a function of (i) the radio frequency energy generated by the excited atoms in the dialysis fluid in the first portion of the cartridge and (ii) a volume of the first portion of the cartridge. ### Claim 6 (depends on 1) The dialysis system of claim 1, further comprising the cartridge. ### Claim 7 (depends on 6) The dialysis system of claim 6, wherein the first section of the first portion of the cartridge defines a first meandering fluid passageway, and the first portion of the cartridge is configured to be disposed within the opening of the magnet assembly. ### Claim 8 (depends on 7) The dialysis system of claim 7, wherein the cartridge is configured such that the first meandering fluid passageway is disposed in the first cavity outside the radio frequency device when the first portion of the cartridge is disposed in the opening of the magnet assembly. ### Claim 9 (depends on 6) The dialysis system of claim 6, wherein the second section of the first portion of the cartridge defines a second meandering fluid passageway. ### Claim 10 (depends on 9) The dialysis system of claim 9, wherein the cartridge defines a fluid inlet port via which the dialysis fluid enters the cartridge, the fluid inlet port having a first flow area and the second meandering fluid passageway having a second flow area that is smaller than the first flow area. ### Claim 11 (depends on 6) The dialysis system of claim 6, wherein the cartridge comprises a second portion configured to be positioned outside the radio frequency device 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. ### Claim 12 (depends on 11) The dialysis system of claim 11, wherein the second portion of the cartridge is configured to be positioned at least partially outside the magnet assembly 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. ### Claim 13 (depends on 11) The dialysis system of claim 11, wherein the second portion of the cartridge defines a fluid passageway that bypasses the first portion of the cartridge. ### Claim 14 (depends on 13) The dialysis system of claim 13, wherein the fluid passageway of the second portion of the cartridge is a substantially straight fluid passageway. ### Claim 15 (depends on 1) The dialysis system of claim 1, wherein the dialysis fluid pump is a blood pump. ### Claim 16 (depends on 1) The dialysis system of claim 1, wherein the dialysis fluid pump is a dialysate pump.