Implantable Dissolved Oxygen Sensor and Methods of Use

Abstract

A sensor is provided for measuring a dissolved oxygen concentration in vivo when implanted at a tissue site and in ex vivo applications. The sensor includes an article comprising a sensing medium retained within the implantable article by an oxygen-permeable material. The sensing medium comprises an MR contrast agent for oxygen. The sensor is configured to indicate the dissolved oxygen concentration of a fluid, e.g., in vivo at the tissue site, when subjected to an MR-based method.

We claim: 
     
         1 . A method of measuring a dissolved oxygen concentration in vivo of a tissue site of a patient, comprising:
 (a) deploying a sensor at the tissue site in the patient, the sensor comprising a sensing medium, the sensing medium comprising a magnetic resonance (MR) contrast agent for oxygen; and thereafter   (b) subjecting the tissue site to electromagnetic radiation and employing an MR-based spectroscopy or other method to analyze the dissolved oxygen concentration in vivo at the tissue site.   
     
     
         2 . The method of  claim 1 , wherein the sensor comprises a reservoir containing the sensing medium. 
     
     
         3 . The method of  claim 1 , wherein the tissue site comprises a tumor. 
     
     
         4 . The method of  claim 3 , wherein the dissolved oxygen concentration of the tissue site is analyzed to evaluate the state of the tumor. 
     
     
         5 . The method of  claim 1 , wherein the dissolved oxygen concentration of the tissue site is analyzed to determine the presence of hypoxia. 
     
     
         6 . The method of  claim 1 , wherein the dissolved oxygen concentration of the tissue site is analyzed to evaluate the effectiveness of a treatment strategy on the patient. 
     
     
         7 . The method of  claim 1 , wherein the dissolved oxygen concentration of the tissue site is analyzed to schedule a therapy on the patient. 
     
     
         8 . The method of  claim 1 , wherein the tissue site is the brain of the patient. 
     
     
         9 . The method of  claim 8 , wherein the dissolved oxygen concentration of the tissue site is analyzed in conjunction with a functional magnetic resonance imaging (MRI) study. 
     
     
         10 . The method of  claim 1 , wherein the dissolved oxygen concentration of the tissue site is analyzed to monitor metabolic activities in specific regions or organs of the body of the patient. 
     
     
         11 . The method of  claim 1 , wherein the MR-based spectroscopy comprises  1 H nuclear magnetic resonance (NMR),  19 Fluorine NMR or MRI. 
     
     
         12 . The method of  claim 1 , wherein the dissolved oxygen concentration of the tissue site is analyzed by measuring T1 relaxation. 
     
     
         13 . The method of  claim 1 , wherein step (b) is repeated multiple times over the course of a treatment. 
     
     
         14 . A method of measuring a dissolved oxygen concentration in vivo of a tissue site of a patient, comprising:
 (a) deploying a sensor at the tissue site in the patient, the sensor comprising a sensing medium, the sensing medium comprising a magnetic resonance (MR) contrast agent for oxygen, wherein the sensor comprises a reservoir containing the sensing medium; and thereafter   (b) subjecting the tissue site to electromagnetic radiation and employing an MR-based spectroscopy or other method to analyze the dissolved oxygen concentration in vivo at the tissue site, wherein the dissolved oxygen concentration of the tissue site is analyzed by measuring T1 relaxation.   
     
     
         15 . The method of  claim 14 , wherein the tissue site comprises a tumor. 
     
     
         16 . The method of  claim 15 , wherein the dissolved oxygen concentration of the tissue site is analyzed to evaluate the state of the tumor. 
     
     
         17 . The method of  claim 14 , wherein step (b) is repeated multiple times over the course of a treatment.