Seeds and Markers for Use in Imaging

Abstract

A contrast marker having a casing and a novel MRI contrast agent comprising metal complexes disposed around, within, or abuting the casing is provided. Such contrast markers may be placed in a strand, with or without a therapy seed, to produce a seeded strand useful for imaging and in connection with brachytherapy.

What is claimed is: 
     
         1 . A contrast agent comprising [(CoCl 2 ) n (C 2 H 5 NO 2 ) 1-n ] (where n=0.5-0.95). 
     
     
         2 . The contrast agent of  claim 1 , wherein the contrast agent is disposed within a casing of a contrast marker. 
     
     
         3 . The contrast agent of  claim 2 , wherein the casing is coated. 
     
     
         4 . The contrast agent of  claim 2 , further comprising a carrier substrate positioned within the casing. 
     
     
         5 . The contrast agent of  claim 2 , further comprising a radioactive therapeutic agent disposed within the casing. 
     
     
         6 . The contrast agent of  claim 2 , wherein the contrast marker is position with a strand. 
     
     
         7 . The contrast agent of  claim 6 , further comprising at least one therapy seed wherein the contrast marker with the contrast agent and the therapy seed are positioned within the strand. 
     
     
         8 . The contrast agent of  claim 6 , further comprising at least one spacer element disposed in the strand with the contrast agent. 
     
     
         9 . The contrast agent of  claim 6 , wherein a radioactive agent selected from the group consisting of palladium-103, iodine-125, and cesium-131 is positioned within a strand. 
     
     
         10 . The contrast agent of  claim 1 , wherein the contrast agent is disposed in a contrast marker and the contrast marker is disposed in a therapy seed. 
     
     
         11 . The contrast agent of  claim 10 , wherein a radioactive agent is disposed in the therapy seed. 
     
     
         12 . The contrast agent of  claim 10 , wherein said therapy seed is coated with the contrast agent. 
     
     
         13 . A method of making a strand comprising:
 providing a polymer strand;   attaching at least one contrast marker with the strand, wherein the contrast marker includes [(CoCl 2 ) n (C 2 H 5 NO 2 ) 1-n ] (where n=0.5-0.95).   
     
     
         14 . The method of  claim 13 , further comprising attaching at least one therapy seed with the strand. 
     
     
         15 . The method of  claim 14 , further comprising positioning a spacer element between the contrast marker and the therapy seed. 
     
     
         16 . A method of making a contrast agent useful in magnetic resonance imaging comprising the steps of:
 determining the T1 relaxation time of a first contrast agent comprising [(CoCl 2 ) n (C 2 H 5 NO 2 ) 1-n ] (where n=0.5-0.95); and   providing a second contrast agent wherein the concentration level of the second contrast agent is adjusted so as to produce substantially similar T1 relaxation times for MR imaging to the first contrast agent.   
     
     
         17 . The method of  claim 16 , wherein the second contrast agent is a contrast agent comprising gadolinium chelated with a multidentate ligand.