Methods and devices for minimally-invasive extraocular delivery of radiation to the posterior portion of 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 on an outer surface of said sclera.

1 - 27 . (canceled) 
     
     
         28 . A hollow fixed shape cannula comprising:
 (a) a distal portion for placement around a portion of a globe of an eye; wherein the distal portion has a radius of curvature between about 9 to 15 mm and an arc length between about 25 to 35 mm; and   (b) a proximal portion having a radius of curvature between about an inner cross-sectional radius of the cannula and about 1 meter; and   (c) an inflection point which is where the distal portion and the proximal portions connect with each other;   wherein an angle θ 1  between a line l 3  tangent to the globe of the eye at the inflection point and the proximal portion is between greater than about 0 degrees to about 180 degrees.   
     
     
         29 . The cannula of  claim 28 , wherein both the distal portion and the proximal portion lie in a plane P 1 . 
     
     
         30 . The cannula of  claim 28 , wherein the distal portion lies in a plane P 1  and the proximal portion lies in a plane P 2 . 
     
     
         31 . The cannula of  claim 28 , wherein the distal portion has a radius of curvature of about 12 mm and the distal portion has an arc length of about 30 mm. 
     
     
         32 . The cannula of  claim 28 , wherein the radius of curvature of the distal portion is constant. 
     
     
         33 . The cannula of  claim 28 , wherein the radius of curvature of the distal portion is variable. 
     
     
         34 . The cannula of  claim 28  having an outer cross sectional shape that is generally round. 
     
     
         35 . The cannula of  claim 28  having an outer cross sectional shape that is oval, rectangular, egg-shaped or trapezoidal. 
     
     
         36 . The cannula of  claim 28  having an internal cross sectional shape configured to allow a RBS to glide through. 
     
     
         37 . The cannula of  claim 28  having an internal cross sectional shape that is generally round. 
     
     
         38 . The cannula of  claim 28  having an internal cross sectional shape that is oval, rectangular, egg-shaped, or trapezoidal. 
     
     
         39 . The cannula of  claim 28 , wherein the cannula further comprises a handle connected to the proximal portion of the cannula. 
     
     
         40 . The cannula of  claim 39 , wherein the handle comprises a radiation shielding pig for shielding a RBS. 
     
     
         41 . The cannula of  claim 28 , wherein a means of advancing a RBS is disposed within the cannula; wherein the cannula is for delivering the RBS to the back of the eye. 
     
     
         42 . The cannula of  claim 41 , wherein the means for advancing a RBS toward a tip of the distal portion 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. 
     
     
         43 . The cannula of  claim 28  having a window located on a side of the distal portion, wherein the side is adjacent to the sclera, wherein the window comprises a radiotransparent material. 
     
     
         44 . The cannula of  claim 28 , wherein the cannula further comprises a protuberance disposed on the distal portion, wherein the protuberance is for resting on the limbus of the eye. 
     
     
         45 . A fixed shape cannula comprising:
 (a) a distal portion for placement around a portion of a globe of an eye; wherein the distal portion has a radius of curvature between about 9 to 15 mm and an arc length between about 25 to 35 mm; and   (b) a proximal portion having a radius of curvature between about an inner cross-sectional radius of the cannula and about 1 meter; and   (c) an inflection point which is where the distal portion and the proximal portions connect with each other;   
       wherein once a distal end of the distal portion is positioned within the vicinity of the target, the proximal portion is curved away from the visual axis as to allow a user to have direct visual access in the eye. 
     
     
         46 . The cannula of  claim 28 , wherein a proximal end of the distal portion of the cannula is tapered such that a circumference of the proximal end is larger than a circumference of a distal end of the distal portion. 
     
     
         47 . 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 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 a line l 3  tangent to the globe of the eye at the inflection point and the proximal portion is between greater than about 0 degrees to about 180 degrees. 
     
     
         48 . The cannula of  claim 47 , 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. 
     
     
         49 . The cannula of  claim 47 , 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. 
     
     
         50 . The cannula of  claim 47 , wherein the inflection point creates a soft bend between the distal portion and the proximal portion. 
     
     
         51 . The cannula of  claim 47 , wherein the distal portion has an arc length of between about 25 to 35 mm. 
     
     
         52 . The cannula of  claim 47 , wherein the proximal portion has an arc length of between about 10 to 75 mm. 
     
     
         53 - 71 . (canceled)