Methods and devices for minimally-invasive delivery of radiation to the eye

Abstract

Methods and devices for minimally-invasive delivery of radiation to the posterior portion of the eye including a cannula comprising a distal portion connected to a proximal portion and a means for advancing a radionuclide brachytherapy source (RBS) toward the tip of the distal portion; a method of introducing radiation to the human eye comprising inserting a cannula between the Tenon's capsule and the sclera of the human eye and emitting the radiation from the cannula.

What is claimed is: 
     
         1 . A cannula with a fixed shape, said cannula comprising:
 a) a distal portion for placement around a portion of a globe of an eye; and   b) a proximal portion connected to the distal portion via an inflection point; wherein the inflection point creates a soft bend between the distal portion and the proximal portion; and   c) a handle extending from the proximal portion, the handle lies on an axis such that the axis does not intersect with the distal portion;   wherein the distal portion has a shape of an arc formed from a connection between two points located on an ellipsoid, the ellipsoid having an x-axis dimension “a”, a y-axis dimension “b,” and a z-axis dimension “c,” wherein “a” is between about 0 to 1 meter, “b” is between about 0 to 1 meter, and “c” is between about 0 to 1 meter;   wherein the proximal portion has a shape of an arc formed from a connection between two points on an ellipsoid, the ellipsoid having an x-axis dimension “d”, a y-axis dimension “e,” and a z-axis dimension “f,” wherein “d” is between about 0 to 1 meter, “e” is between about 0 to 1 meter, and “f” is between about 0 to 1 meter; and   wherein an angle θ 1  between (i) a line I 3  tangent to the inflection point between the distal portion and the proximal portion and (ii) a line I 4  parallel to the handle extending from the proximal portion is between greater than about 0 degrees to about 180 degrees; wherein said cannula is for placing under a Tenon's capsule.   
     
     
         2 . The cannula of  claim 1 , wherein “a” is between about 0 to 50 mm, “b” is between about 0 and 50 mm, and “c” is between about 0 and 50 mm. 
     
     
         3 . The cannula of  claim 1 , wherein “d” is between about 0 to 50 mm, “e” is between about 0 and 50 mm, and “f” is between about 0 and 50 mm. 
     
     
         4 . The cannula of  claim 1 , wherein the distal portion has an arc length of between about 25 to 35 mm. 
     
     
         5 . The cannula of  claim 1 , wherein the proximal portion has an arc length of between about 10 to 75 mm. 
     
     
         6 . The cannula of  claim 1 , wherein at least a portion of the cannula is hollow. 
     
     
         7 . The cannula of  claim 1 , wherein the distal portion and proximal portion are both hollow. 
     
     
         8 . The cannula of  claim 1 , wherein at least a portion of the cannula is solid. 
     
     
         9 . The cannula of  claim 1 , wherein the distal portion and proximal portion are both solid. 
     
     
         10 . The cannula of  claim 1 , further comprising a radionuclide brachytherapy source (RBS) disposed at a tip of the distal portion. 
     
     
         11 . The cannula of  claim 10 , wherein the tip of the distal portion has a diameter or width that is greater than that of the distal portion. 
     
     
         12 . The cannula of  claim 1 , having an outer cross sectional shape that is round or oval. 
     
     
         13 . The cannula of  claim 6 , having an internal cross sectional shape that is round or oval. 
     
     
         14 . The cannula of  claim 6 , having an internal cross sectional shape configured to allow a radionuclide brachytherapy source (RBS) to glide through. 
     
     
         15 . The cannula of  claim 6 , wherein an advancing mechanism is disposed in the cannula for advancing a radionuclide brachytherapy source (RBS) from a starting position in the cannula to at or near a tip of the distal portion of the cannula. 
     
     
         16 . The cannula of  claim 15 , wherein the advancing mechanism is selected from the group consisting of a guide wire, a non-wire plunger, an air pressure mechanism, a vacuum mechanism, a hydrostatic pressure mechanism employing a fluid, or a combination thereof. 
     
     
         17 . The cannula of  claim 1 , wherein the handle comprises a radiation shielding pig for shielding a radionuclide brachytherapy source (RBS). 
     
     
         18 . The cannula of  claim 1 , wherein the cannula further comprises a protuberance disposed on the distal portion.