Methods and apparatus for intraocular brachytherapy

• US 20060111605A1
• Filed: 09/15/2005
• Published: 05/25/2006
• Est. Priority Date: 02/12/2004
• Status: Active Grant

• Current Assignee: Oraya Therapeutics, Inc.
• Original Assignee: Neovista, Inc.
• Inventors: Larsen, Charles E., Humayun, Mark, Trip, Roelof, Hillstead, Richard A., Fritz, Eberhard, Pintaske, Rainer, deJuan, Eugene
• Granted Patent: US 7,563,222 B2
• Time in Patent Office: Days
• US Class Current: 600/1
• CPC Class Codes: A61N 2005/1058 using ultrasound imaging
• CPC Class Codes: A61N 5/1017 Treatment of the eye, e.g. for "macular degeneration"
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam

Abstract

A method for performing intraocular brachytherapy and an apparatus for performing the same is disclosed. The apparatus preferably comprises a hand-held delivery device that advances a radiation source into an associated cannula or probe that is positioned adjacent the target tissue. The handpiece provides for shielded storage of the radiation source when retracted from the cannula and includes a slider mechanism for advancing and retracting the radiation source. The radiation source is mounted to a wire that has a flexible distal end and a relatively stiffer proximal end.

Claims

1. A method for epiretinal treatment of a subretinal target tissue in an eye having a sclera and a retina, comprising the steps of:

introducing an ionizing radiation source through the sclera into the interior of the eye;

locating the radiation source with respect to the subretinal target tissue to expose the target tissue to radiation passing through the retina; and

irradiating the target tissue through the retina with an effective amount of radiation.

2. The method of claim 1 wherein the radiation source delivers a dose of between about 7 and 50 GY.

3. The method of claim 2 wherein the dose is between approximately 20 and 30 GY.

4. The method of claim 3 wherein the dose is approximately 24 GY.

5. The method of claim 1 wherein the radiation source is a beta emitting isotope having a source activity level of between approximately 5-20 mCi.

6. The method of claim 1 wherein the radiation source is a beta emitting isotope having a source activity of between approximately 11-13 mCi.

7. The method of claim 1 wherein the radiation source is spaced from 2-6 mm from the target tissue.

8. A device for local, directional delivery of radiation to intraocular target tissue comprising a radiation source;

a cannula sized for intraocular insertion into an eye and having a proximal end and a distal end for containing the radiation source; and

a housing to which the proximal end of the cannula is secured, the cannula being secured to the housing by a hub extending external to the housing and adapted to be gripped by an operator.

9. The device of claim 8 wherein the hub has a generally cylindrical proximal section, a generally-conical distal section and at least one irregular surface to provide a reference for orientation of the cannula.

10. The device of claim 9 wherein the irregular surface comprises a pair of opposed flat surfaces, the flat surfaces lying in planes parallel to one another.

11. The device of claim 8 wherein the hub is made of a radiation-shielding material.

12. The device for local, directional delivery of radiation to intraocular target tissue comprising:

a radiation source having an outside diameter;

a housing for storing the radiation source and moving the radiation source between a retracted position and a treatment position; and

a cannula sized for intraocular insertion into an eye, the cannula having an inside diameter that is larger then the outside diameter of the radiation source so as to permit relatively free movement of the radiation source between the proximal end and the distal end of the cannula as it is moved between the retracted and treatment positions, the distal end of the cannula comprising an assembly of a distal-most atraumatic tip secured to the cannula by an intermediate cover sleeve, the cover sleeve having an inside diameter approximately the same as the inside diameter of the cannula, and a guide sleeve on the interior of the cover sleeve, the guide sleeve lying along a partial radial location of the cover sleeve and having a thickness corresponding to approximately the difference between the outside diameter of the radiation source and the inside diameter of the cannula so as to bias the radiation source to a position adjacent the wall of the cover sleeve when the radiation source is in the treatment position.

13. The device of claim 12 in which the guide sleeve has a proximal end that is inclined.

14. The device of claim 13 wherein the guide sleeve is positioned within the cover sleeve on a side away from the target tissue that is to be irradiated by the radiation source.