ORTHOVOLTAGE RADIOSURGERY

• US 20110170664A1
• Filed: 03/22/2011
• Published: 07/14/2011
• Est. Priority Date: 10/16/2006
• Status: Active Grant

• Current Assignee: Carl Zeiss Meditec Incorporated (Carl-Zeiss-Stiftung)
• Original Assignee: Oraya Therapeutics, Inc.
• Inventors: Gertner, Michael, Herron, Matt, Hansen, Steven D., Chell, Erik
• Granted Patent: US 8,442,185 B2
• Time in Patent Office: Days
• US Class Current: 378/65
• CPC Class Codes: A61B 6/506 for diagnosis of nerves
• CPC Class Codes: A61B 6/508 for non-human patients
• CPC Class Codes: A61N 2005/1019 Sources therefor
• CPC Class Codes: A61N 2005/1022 Generators, e.g. X-ray tubes
• CPC Class Codes: A61N 2005/105 using a laser alignment system
• CPC Class Codes: A61N 2005/1051 using an active marker markers in general A61B90/39
• CPC Class Codes: A61N 2005/1059 using cameras imaging the patient
• CPC Class Codes: A61N 2005/1091 Kilovoltage or orthovoltage range photons
• CPC Class Codes: A61N 2005/1097 Means for immobilizing the patient
• CPC Class Codes: A61N 5/10 X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy A61N5/01 takes precedence
• CPC Class Codes: A61N 5/1001 using radiation sources introduced into or applied onto the body; brachytherapy
• CPC Class Codes: A61N 5/1017 Treatment of the eye, e.g. for "macular degeneration"
• CPC Class Codes: A61N 5/1045 using a multi-leaf collimator, e.g. for intensity modulated radiation therapy or IMRT
• CPC Class Codes: A61N 5/1048 Monitoring, verifying, controlling systems and methods
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam
• CPC Class Codes: A61N 5/1064 for adjusting radiation treatment in response to monitoring
• CPC Class Codes: A61N 5/1065 Beam adjustment
• CPC Class Codes: A61N 5/1067 in real time, i.e. during treatment
• CPC Class Codes: A61N 5/1077 Beam delivery systems
• CPC Class Codes: A61N 5/1084 for delivering multiple intersecting beams at the same time, e.g. gamma knives

Abstract

A radiosurgery system is described that delivers a therapeutic dose of radiation to a target structure in a patient. In some embodiments, inflammatory ocular disorders are treated, specifically macular degeneration. In some embodiments, ocular structures are placed in a global coordinate system, based on ocular imaging, which leads to direction of an automated positioning system. In some embodiments, the position of an ocular structure is tracked and related to a radiosurgery system. In some embodiments, a treatment plan is utilized for a specific disease to be treated and/or structures to be avoided. In some embodiments, a fiducial aids in positioning the system. In some embodiments, a reflection off the eye is used to aid in positioning. In some embodiments, radiodynamic therapy is described in which radiosurgery is used in combination with other treatments and can be delivered concomitant with, prior to, or following other treatments.

Claims

1. A method of treating an eye with radiotherapy, comprising:

emitting a first x-ray beam, having a maximal energy, toward a target in an eye from an x-ray source located from a first position relative to the target, the x-ray source having an anode with a non-zero size;

the first x-ray beam being configured such that a first beamspot at the target in the eye resulting from the first x-ray beam emission has a cross-sectional dimension that is no more than about 10% greater than a cross-sectional dimension of a second beamspot at the target;

the second beamspot resulting from a second x-ray beam, having the same maximal energy as the first x-ray beam, emitted from the x-ray source, at the first position, having a point-source anode.

2. The method of claim 1, wherein the first x-ray beam has a maximal energy of less than about 500 keV.

3. The method of claim 1, wherein the first x-ray beam has a maximal energy of up to about 100 keV.

4. The method of claim 1, further comprising:

(a) applying an ocular stabilizing device to the treated eye that limits or prevents eye movement during a selected treatment interval; and

(b) continuing the emitting of the first x-ray beam for the selected treatment interval to apply a selected treatment radiation dose to the target in an eye.

5. The method of claim 1, further comprising:

(a) using an ocular tracking device, determining when the eye is aligned with a treatment axis;

(b) continuing the emitting of the first x-ray beam when the eye is aligned with the treatment axis; and

(c) discontinuing the emitting of the first x-ray beam in the event that the eye is not aligned, within a determined threshold of alignment, with the treatment axis.

6. The method of claim 1, wherein the first position is within about 50 cm of the target.

7. The method of claim 1, wherein the first position is located less than or equal to about 200 mm from the target during the emitting.

8. The method of claim 1, wherein the anode non-zero size comprises a cross-sectional dimension of about 5.5 mm.

9. The method of claim 1, wherein the anode non-zero size comprises a cross-sectional dimension less than or equal to about 2.0 mm.

10. A method of treating an eye with radiotherapy, comprising:

emitting, from an x-ray source toward a target region in an eye, a first collimated x-ray beam having a beam axis, so as to administer a radiation dose to a target area of the target region, the x-ray source having a maximal energy, an anode with a non-zero size, the x-ray source being located at a first position relative to the target region during the emitting, and the first beam having;

(a) a beam cross-section that is perpendicular to the beam axis, the cross-section having a centroid and a dimension defining a radial direction outward from the centroid;

(b) a maximal dose region about the centroid having a maximum dose intensity; and

(c) an outer dose drop-off region having a decreasing dose intensity distribution outward in the radial direction and extending to a delimiting dimension defined by a dose intensity of 20% of the maximum dose intensity;

wherein the beam is further configured so that a first beamspot at the target area in the eye resulting from the emitting the first beam has a delimiting dimension that is no more than about 10% greater than a delimiting dimension of a second beamspot at the target area, which second beamspot would result from a second collimated x-ray beam, having the same maximum dose intensity as the first beam, emitted from the x-ray source, at the first position, having a point-source anode and the same maximal energy as the first x-ray source.

11. The method of claim 10, wherein the first x-ray beam has a maximal energy of up to about 500 keV.

12. The method of claim 10, further comprising:

applying an ocular stabilizing device to the eye that limits or prevents eye movement during a selected treatment interval; and

continuing the emitting of the first x-ray beam for the selected treatment interval to apply a treatment radiation dose to the target area.

13. The method of claim 10, further comprising:

using an ocular tracking device, determining if the eye is aligned with a treatment axis; and

continuing the emitting of the first x-ray beam when the eye is aligned with the treatment axis; and

discontinuing the emitting of the first x-ray beam when the eye is not aligned, within a threshold of alignment, with the treatment axis.

14. The method of claim 10, wherein the first x-ray source has an anode with a size less than or equal to about 2.0 mm.

15. The method of claim 10, wherein the first position is located less than or equal about 50 cm from the target area during the emitting.

16. The method of claim 10, wherein the first position is located less than or equal about 200 mm from the target area during the emitting.

17. The method of claim 10, wherein the first x-ray beam is collimated by a collimator having an exit plane positioned at a distance of less than or equal to about 160 mm from the target area.

18. The method of claim 10, wherein the first x-ray beam is collimated by a collimator having an exit plane positioned at a distance of less than or equal to about 50 mm from the target area.

19. The method of claim 10, wherein the delimiting dimension of the first collimated x-ray beam is less than or equal to about 20 mm.

20. The method of claim 10, wherein the delimiting dimension of the first collimated x-ray beam is less than or equal to about 2 mm.