Intracorporeally introducible suspension of ferromagnetic particles and method using same for spatially resolved body temperature monitoring

• US 6,280,384 B1
• Filed: 04/15/1999
• Issued: 08/28/2001
• Est. Priority Date: 04/16/1998
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Loeffler, Ralf
• Primary Examiner(s): Casler, Brian L.
• Application Number:
  US09/292,611
• Time in Patent Office: 866 Days
• Field of Search: 600/410, 600/412, 600/420, 600/549, 424/9.3, 424/9.32, 424/9.323, 424/9.36, 424/9.34, 424/9.35, 424/9.322, 424/9.321
• US Class Current: 600/412
• CPC Class Codes: G01K 7/38 the variations of temperature influencing the magnetic permeability

Abstract

In a method for spatially resolved temperature monitoring in an examination subject, a suspension of ferromagnetic microparticles is intracorporeally introduced into the body Curie temperature of which substance corresponds to a desired temperature limit value. By means of an MR measurement, a spatially resolved representation of the body is obtained with artifacts that are caused by the substance being in the ferromagnetic state being employed as a criterion for determining that the temperature limit value has not yet been reached.

Claims

1. A method for spatially resolved temperature monitoring in a living body, comprising the steps of:

providing a ferromagnetic substance having a Curie temperature corresponding to a predetermined body temperature limit value;

intracorporeally introducing said substance into a living body;

obtaining magnetic resonance data from said living body with said substance intracorporeally introduced therein;

producing an image of said living body from said magnetic resonance data, said image containing artifacts due to said substance as long as said Curie temperature is not reached; and

determining, from a presence of said artifacts in said image, that said body temperature limit value has not been reached.

2. A method as claimed in claim 1 wherein the step of obtaining magnetic resonance data comprises obtaining magnetic resonance data from protons in said living body.

3. A method as claimed in claim 1 wherein the step of obtaining magnetic resonance data comprises conducting a magnetic resonance imaging pulse sequence having an image contrast which is sensitive to susceptibility changes.

4. A method as claimed in claim 1 wherein the step of providing a ferromagnetic substance comprises providing a palladium-nickel alloy as said ferromagnetic substance.

5. A method as claimed in claim 4, wherein the step of providing a palladium-nickel alloy comprises providing a palladium-nickel alloy having a nickel content of approximately of 26 at. %.

6. A method as claimed in claim 1 wherein the step of intracorporeally introducing said substance comprises implanting said substance in said living body.

7. A method as claimed in claim 1 wherein the step of intracorporeally introducing said substance comprises forming said substance into a needle and introducing said needle into said living body.

8. A method as claimed in claim 1 wherein the step of providing a ferromagnetic substance comprises providing ferromagnetic microparticles as said ferromagnetic substance, and comprising the additional step of encapsulating said ferromagnetic microparticles so as to be inert to metabolization by said living body, and wherein the step of intracorporeally introducing said substance comprises injecting a suspension of said encapsulated ferromagnetic microparticles.