Radiation delivery devices and methods for their manufacture

Abstract

Radiation delivery devices useful in brachytherapy which employ radioactive palladium-103 as the radiation source material are disclosed. Certain embodiments of the disclosed radiation delivery devices have the advantages that they can be fabricated with the desired specific activity, that the self-shielding effects of the devices are minimized, that the radioactive source material is bonded to a substrate in a manner which substantially prevents it from becoming detached, and that a variety of customizable radiation delivery devices can be made using the concepts of the invention. Also disclosed are processes for bonding radiation source material to various substrates using electroless plating, chemical vapor deposition and polymer matrices. These processes have the advantage that they can be applied to bond the radiation source material to a wide variety of substrates including different substrate materials and differently shaped substrates, thereby providing the ability to tailor the radiation delivery devices to the specific requirements of a particular brachytherapy treatment.

1 . A radiation delivery device, which comprises: 
 a flexible substrate selected from the group consisting of flexible fiber and flexible film formed from a radiation compatible material and which is sufficiently flexible to deform under its own weight, and    a sufficient amount of radioactive palladium-103 bonded to the outer surface of the substrate to provide an apparent activity of the radiation delivery device, as measured adjacent to the surface of the substrate, of from about 0.5 μCi to about 300 Ci/device, and wherein the radioactive palladium-103 forms at least a portion of the outer surface of the radiation delivery device such that the radioactive palladium-103 can be positioned closely adjacent to, or in direct contact with, a location to be treated with radiation.    
     
     
         2 . A radiation delivery device as claimed in  claim 1 , wherein the radioactive palladium-103 is bonded to the outer surface of the substrate by a deposition process selected from the group consisting of electroless plating, electroplating, sputtering, ion implantation, physical vapor deposition and chemical vapor deposition.  
     
     
         3 . A radiation delivery device as claimed in  claim 1 , wherein the radioactive palladium-103 is dispersed in an outermost portion of the substrate.  
     
     
         4 . A radiation delivery device as claimed in  claim 1 , wherein the radioactive palladium-103 is dispersed in a layer of material located on the outermost surface of the substrate.  
     
     
         5 . A radiation delivery device as claimed in  claim 1 , wherein the radioactive palladium-103 is substantially homogeneously dispersed over the entire outer surface of the substrate to thereby provide a substantially uniform distribution of radiation from the radiation delivery device.  
     
     
         6 . A radiation delivery device as claimed in  claim 1 , wherein the radioactive palladium-103 is non-uniformly dispersed over the outer surface or within the outer surface of the substrate to thereby provide a directional distribution of radiation from the radiation delivery device.  
     
     
         7 . A radiation delivery device as claimed in  claim 1 , wherein the substrate comprises at least one material selected from the group consisting of: polymeric materials, ceramic materials, hydrogels, metals, graphite and ion exchange resins.  
     
     
         8 . A radiation delivery device as claimed in  claim 1 , wherein the substrate comprises a flexible material selected from the group consisting of elastomers, gels and foams.  
     
     
         9 . A radiation delivery device as claimed in  claim 1 , further comprising a protective coating layer located on the outside of the radioactive layer.  
     
     
         10 . A radiation delivery device as claimed in  claim 1 , having an apparent activity of from about 0.5 mCi to about 30 Ci per device.  
     
     
         12 . A radiation delivery device which comprises: 
 a non-conductive substrate; and    a sufficient amount of radioactive palladium-103 bonded to the substrate to provide an apparent activity of the radiation delivery device, as measured adjacent to the surface of the substrate, of from about 0.5μ to about 300 Ci/device, and wherein the radioactive palladium-103 comprises carrier-free palladium-103.    
     
     
         13 . A radiation delivery device as claimed in  claim 12 , wherein the radioactive palladium-103 is bonded to the outer surface of the substrate by a deposition process selected from the group consisting of electroless plating, electroplating, sputtering, ion implantation, physical vapor deposition and chemical vapor deposition.  
     
     
         13 . A deformable radiation delivery device which comprises: 
 a deformable substrate, and    a sufficient amount of radioactive palladium-103 bonded to the substrate to provide an apparent activity of the radiation delivery device, as measured adjacent to the surface of the substrate, of from about 0.5 μCi to about 300 Ci/device, and wherein the radioactive palladium-103 is bonded to the deformable substrate in a manner whereby substantially no radioactive palladium-103 detaches from the deformable substrate under normal use conditions.    
     
     
         14 . A deformable radiation delivery device as claimed in  claim 13 , wherein the radioactive palladium-103 comprises carrier-free palladium-103.  
     
     
         15 . A deformable radiation delivery device as claimed in  claim 13 , wherein the deformable substrate comprises an elastomer, gel or foam.  
     
     
         16 . A deformable radiation delivery device as claimed in  claim 13 , further comprises a deformable coating of a biocompatible material on the outer surface of the radiation delivery device.  
     
     
         17 . A process for bonding a material selected from the group consisting of palladium-102, palladium-104, radioactive palladium-103, carrier-free palladium-103, naturally occurring palladium, palladium enriched in palladium-102, palladium-104 enriched palladium and mixtures thereof, onto a substrate which comprises the steps of: 
 treating the surface of the substrate by treating the substrate with a material selected from the group consisting of a tin salt, a platinum salt and a palladium salt;    activating the treated substrate surface by contacting the treated substrate surface with a compound selected from the group consisting of palladium salts and platinum salts, and mixtures thereof; and    contacting the activated substrate surface with a solution of a radiation source material selected from the group consisting of palladium-102, palladium-104, radioactive palladium-103, carrier-free palladium-103, naturally occurring palladium, palladium enriched in palladium-102 or palladium-104 and mixtures thereof, in a suitable solvent for a sufficient time to bond a sufficient of amount of the radiation source material to the substrate to provide a radiation delivery device with an apparent activity of the radiation delivery device, as measured adjacent to the surface of the substrate, of from about 0.5 μCi to about 300 Ci/device.    
     
     
         18 . A process in accordance with  claim 17 , wherein the radiation source material comprises carrier-free palladium-103.  
     
     
         19 . A process in accordance with  claim 18 , wherein the substrate comprises a non-conductive material.  
     
     
         20 . A radiation delivery device produced by the process of  claim 17 .  
     
     
         21 . A directional radiation delivery device which comprises: 
 a substrate;    a radiation source material including at least some radioactive palladium-103; and    a shielding material which substantially reduces the radiation emitted by the radiation source material in at least one direction relative to the radiation delivery device.    
     
     
         22 . A radiation delivery device which comprises: 
 a biocompatible material in the form of an object selected from the group consisting of a housing, a strand, a fibrous material, a mesh, a flexible hollow tube and a matrix; and    a plurality of radiation emitting sources associated with said biocompatible material;    wherein said radiation emitting sources each comprise:    a substrate; and    a radiation source selected from the group consisting of pellets and microspheres and including at least some radioactive palladium-103 bonded to the substrate.    
     
     
         23 . A radiation delivery device as claimed in  claim 22 , wherein the radiation source material is bonded to the outer surface of the pellets or microspheres.  
     
     
         24 . A radiation delivery device as claimed in  claim 22 , wherein the radiation emitting sources comprise pellets or microspheres and the radiation source material is dispersed in the substrate which forms the pellets or microspheres.  
     
     
         25 . A radiation delivery device as claimed in  claim 24 , wherein the radiation source material is dispersed only in an outermost portion of the microspheres.  
     
     
         26 . A radiation delivery device as claimed in  claim 22 , wherein the substrate is in the form of a fiber strand and the radioactive material is coated on an outer portion of the fiber strand.  
     
     
         27 . A radiation delivery device as claimed in  claim 22 , wherein the substrate is in the form of a flexible hollow tube.  
     
     
         28 . A radiation delivery device as claimed in  claim 27 , wherein the radioactive material is located on the inner surface of the flexible hollow tube.:  
     
     
         29 . A radiation delivery device which comprises: 
 a flexible hollow tube; and    a radiation emitting source located with the flexible hollow tube; wherein said radiation emitting source comprises:    a flexible substrate selected from the group consisting of elastomers, foams and gels; and 
 a radiation source material including at least some radioactive palladium-103 dispersed or dissolved in the substrate.