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 . A method of irradiating a target of an eye in a patient, said method comprising:
 (a) inserting a cannula into a potential space under a Tenon's capsule of the eye of the patient, the cannula configured to have a radionuclide brachytherapy source (RBS) at a treatment position,   (b) observing through a pupil the position of the treatment position in a posterior pole of the eye,   (c) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the treatment position, the fine positioning is achieved when the treatment position is over a target,   (d) irradiating the target with the RBS.   
   
   
       2 . The method of  claim 1 , wherein the Tenon's capsule guides insertion of the cannula and provides positioning support for the cannula. 
   
   
       3 . The method of  claim 1 , wherein the target is located on a vitreous side of the eye. 
   
   
       4 . The method of  claim 1 , wherein the RBS is loaded into the cannula before the cannula is inserted. 
   
   
       5 . The method of  claim 1 , wherein the RBS is loaded into the cannula after the cannula is inserted. 
   
   
       6 . The method of  claim 1 , wherein the cannula is a fixed shape cannula. 
   
   
       7 . The method of  claim 1 , wherein the cannula is a flexible cannula, including an endoscope. 
   
   
       8 . The method of  claim 1 , wherein the target is a lesion associated with a retina of the eye. 
   
   
       9 . The method of  claim 8 , wherein the lesion is a neovascular lesion. 
   
   
       10 . The method of  claim 8 , wherein the lesion is a benign growth or a malignant growth. 
   
   
       11 . The method of  claim 1 , wherein the RBS provides a dose rate of between about 0.1 to 1 Gy/min to the target. 
   
   
       12 . The method of  claim 1 , wherein the RBS provides a dose rate of between about 1 to 10 Gy/min to the target. 
   
   
       13 . The method of  claim 1 , wherein the RBS provides a dose rate of between about 10 to 20 Gy/min to the target. 
   
   
       14 . The method of  claim 1 , wherein the RBS provides a dose rate of between about 20 to 30 Gy/min to the target. 
   
   
       15 . The method of  claim 1 , wherein the RBS provides a dose rate of between about 30 to 40 Gy/min to the target. 
   
   
       16 . The method of  claim 1 , wherein the RBS provides a dose rate of between about 40 to 50 Gy/min to the target. 
   
   
       17 . The method of  claim 1 , wherein the RBS provides a dose rate of between about 50 to 75 Gy/min to the target. 
   
   
       18 . The method of  claim 1 , wherein the RBS provides a dose rate of between about 75 to 100 Gy/min to the target. 
   
   
       19 . The method of  claim 1 , wherein the cannula is inserted at a limbus of the eye. 
   
   
       20 . The method of  claim 1 , wherein the cannula is inserted at a point posterior to a limbus of the eye. 
   
   
       21 . The method of  claim 1 , wherein the cannula is inserted at a point between a limbus and a fornix of the eye. 
   
   
       22 . A method of irradiating a target of an eye in a patient, said method comprising:
 (a) inserting a cannula into a potential space under a Tenon's capsule of the eye of the patient;   (b) placing a distal portion of the cannula on or near a sclera behind the target;   (c) observing through a pupil the position of the distal portion of the cannula in a posterior pole of the eye;   (d) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the distal portion of the cannula, the fine positioning is achieved when a treatment position of the distal portion is positioned over a target,   (e) advancing a RBS through the cannula to the treatment position of the distal portion via a means for advancing a RBS; and   (f) exposing the target to the RBS.   
   
   
       23 . The method of  claim 22 , wherein the cannula is inserted at a limbus of the eye. 
   
   
       24 . The method of  claim 22 , wherein the cannula is inserted at a point posterior to a limbus of the eye. 
   
   
       25 . The method of  claim 22 , wherein the cannula is inserted at a point between a limbus and a fornix of the eye. 
   
   
       26 . The method of  claim 22 , wherein the distal portion of the cannula is designed 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;
 the cannula further comprising a proximal portion having a radius of curvature between about an inner cross-sectional radius of the cannula and about 1 meter; and 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.   
   
   
       27 . The method of  claim 1 , wherein the cannula is tapered, having a larger circumferential area at a portion of the cannula that remains in the Tenon's capsule upon insertion. 
   
   
       28 . A method of delivering a radiation to an eye, said method comprising irradiating a target on a vitreous side of the eye from an outer surface of a sclera, wherein the target receives a dose rate of greater than about 10 Gy/min, the method further comprises:
 (a) observing through a pupil the position of the treatment position in a posterior pole of the eye,   (b) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the treatment position, the fine positioning is achieved when the treatment position is over a target.   
   
   
       29 . The method of  claim 28 , wherein a hollow cannula is used to deliver a RBS to the sclera region corresponding to the target, the cannula is inserted between a Tenon's capsule and a sclera of the eye; the cannula having a fixed shape, said cannula comprises a distal portion for placement on a portion of the globe of the eye and a proximal portion connected to the distal portion via an inflection point. 
   
   
       30 . The method of  claim 28 , wherein the RBS provides a dose rate of greater than about 11 Gy/min to the target. 
   
   
       31 . The method of  claim 28 , wherein the RBS provides a dose rate of greater than about 12 Gy/min to the target. 
   
   
       32 . The method of  claim 28 , wherein the RBS provides a dose rate of greater than about 13 Gy/min to the target. 
   
   
       33 . The method of  claim 28 , wherein the RBS provides a dose rate of greater than about 14 Gy/min to the target. 
   
   
       34 . The method of  claim 28 , wherein the RBS provides a dose rate of greater than about 15 Gy/min to the target. 
   
   
       35 . The method of  claim 28 , wherein the RBS provides a dose rate between about 15 to 30 Gy/min to the target. 
   
   
       36 . The method of  claim 28 , wherein the RBS provides a dose rate between about 30 to 60 Gy/min to the target. 
   
   
       37 . The method of  claim 28 , wherein the RBS provides a dose rate between about 60 to 100 Gy/min to the target. 
   
   
       38 . The method of  claim 28 , wherein the target is a neovascular tissue. 
   
   
       39 . The method of  claim 28 , wherein the target is a macula. 
   
   
       40 . The method of  claim 28 , wherein the target is a benign growth or a malignant growth. 
   
   
       41 . A method of irradiating a target associated with a retina of an eye in a patient, said method comprising placing a radionuclide brachytherapy source (“RBS”) at or near a sclera portion of the eye that corresponds with the target, the RBS irradiates the target through the sclera, wherein more than 1% of a radiation from the RBS is deposited on a tissue at or beyond a distance of 1 cm from the RBS, the method further comprises:
 (a) observing through a pupil the position of the treatment position in a posterior pole of the eye,   (b) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the treatment position, the fine positioning is achieved when the treatment position is over a target.   
   
   
       42 . The method of  claim 41 , wherein about 1% to about 15% of the radiation from the RBS is deposited on a tissue at or beyond a distance of 1 cm from the RBS. 
   
   
       43 . The method of  claim 41 , wherein about less than 99% of the radiation from the RBS is deposited on a tissue at a distance less than 1 cm from the RBS. 
   
   
       44 . A method of irradiating a target of an eye in a patient, said method comprising inserting a cannula between a Tenon's capsule and a sclera of the eye of the patient,
 the cannula has a radionuclide brachytherapy source (“RBS”) at a distal end, wherein the RBS is positioned over the sclera portion that corresponds with the target, the RBS irradiates the target through the sclera;   wherein the target receives a dose rate of greater than about 10 Gy/min;   wherein the cannula is a fixed shape cannula; and   wherein the RBS is loaded into the cannula after the cannula is inserted;   the method further comprising:   (a) observing through a pupil the position of a treatment position in a posterior pole of the eye,   (b) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the treatment position, the fine positioning is achieved when the treatment position is over a target.   
   
   
       45 . The method of  claim 44 , wherein the target is a lesion associated with a retina of the eye. 
   
   
       46 . The method of  claim 45 , wherein the lesion is a neovascular lesion.