Radiation Containing Seeds and Method for High Visibility Magnetic Imaging

Abstract

A radioactive seed and method for making a radioactive seed with selective magnetic imaging characteristics are provided. The seed comprises a housing which may include a metal shell for at least partially enclosing a radioactive material. The shell encloses a rod having a nickel layer with a phosphorous content, wherein the phosphorous content comprises a level of phosphorous sufficient, when the seed is implanted in tissue, to provide a defined magnetic resonance signature of the seed while substantially eliminating gross artifacts in the magnetic resonance image.

1 . A radioactive seed for at least partially enclosing a radioactive material wherein the seed is configured such that the seed has desired magnetic characteristics. 
   
   
       2 . The radioactive seed of  claim 1  wherein the seed is configured by providing the seed with a metallic composition having the desired magnetic characteristics. 
   
   
       3 . The radioactive seed of  claim 2  wherein the metallic composition comprises providing the seed with an iron content such that the seed has the desired magnetic characteristics. 
   
   
       4 . The radioactive seed of  claim 2  wherein the seed is configured by providing a housing with a selected type of stainless steel such that the housing has the desired magnetic characteristics. 
   
   
       5 . The radioactive seed of  claim 1  wherein the seed is configured by providing the seed with a predetermined metal content and subjecting the seed to a magnetic field such that the housing has the desired magnetic characteristics. 
   
   
       6 . The radioactive seed of  claim 1  wherein the seed comprises:
 a metal shell for at least partially enclosing a radioactive material; and   a rod traversing the shell comprised of a phosphorus-containing nickel layer, wherein the phosphorous content comprises a level of phosphorous sufficient, when the seed is implanted in tissue, to provide a defined magnetic resonance signature of the seed while substantially eliminating gross artifacts in the magnetic resonance image.   
   
   
       7 . The radioactive seed of  claim 6  wherein the metal shell is comprised of titanium. 
   
   
       8 . The radioactive seed of  claim 6  wherein the phosphorous content is applied to the rod through an electroplating process. 
   
   
       9 . The radioactive seed of  claim 6  wherein the phosphorous content is applied to the rod through a deposition process. 
   
   
       10 . A method for making a radioactive seed comprising the steps of:
 providing a housing for at least partially enclosing a radioactive material; and   configuring the housing such that the radioactive seed has desired magnetic characteristics.   
   
   
       11 . The method of  claim 10  wherein the housing is configured by providing the housing with a metallic composition having the desired magnetic characteristics. 
   
   
       12 . The method of  claim 10  wherein the housing is provided with an iron content such that the housing has the desired magnetic characteristics. 
   
   
       13 . The method of  claim 10  wherein the housing is configured by providing the housing with a selected type of stainless steel such that the housing has the desired magnetic characteristics. 
   
   
       14 . The method of  claim 10  wherein the housing is configured by providing the housing with a predetermined metal content and subjecting the housing to a magnetic field such that the housing has the desired magnetic characteristics. 
   
   
       15 . The method of  claim 10  wherein the housing comprises a rod for insertion in a shell of a radioactive seed and further comprising the steps of:
 exposing the rod to a phosphorous-containing nickel material;   providing absorption of phosphorous and nickel into the rod; and   adjusting the concentration of the phosphorous such that the radioactive seed has the desired magnetic characteristics.   
   
   
       16 . The method of  claim 15  wherein the desired magnetic characteristics are determined such that when the radioactive seed is placed in tissue and a magnetic resonance image is taken thereof, a level of phosphorous absorbed in the nickel layer of the rod is sufficient to substantially eliminate gross artifacts in the magnetic resonance image while providing visibility of the seed on the magnetic resonance image. 
   
   
       17 . The method of  claim 16  further comprising the step of selecting the level of phosphorous contained in the nickel layer of the rod such that visibility of the seed in the magnetic resonance image is optimized. 
   
   
       18 . The method of  claim 15  further comprising the steps of:
 removing the rod from exposure to the nickel-phosphorous material;   inserting the rod in the seed;   inserting the seed in tissue;   generating a magnetic resonance image of the seed in the tissue; and   changing the concentration of phosphorous in the nickel layer of the rod based on a characteristic of the magnetic resonance image.   
   
   
       19 . The method of  claim 18  wherein the step of exposing comprises the steps of:
 selecting a percentage of phosphorous in a bath; and   selecting a percentage of nickel in the bath; and   submerging the rod in the bath for a predetermined time period.   
   
   
       20 . A method of making a radioactive seed comprising the steps of:
 providing a shell; and   inserting a rod in the shell, the rod having a nickel layer with a phosphorous content wherein the phosphorous content comprises a level of phosphorous sufficient, when the seed is implanted in tissue, to provide a defined magnetic resonance signature of the seed while substantially eliminating gross artifacts in the magnetic resonance image.