Orthovoltage radiosurgery
A radiosurgery system is described that is configured to deliver 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, other disorders or tissues of a body are treated with the dose of radiation. In some embodiments, the target tissues are placed in a global coordinate system based on ocular imaging. In some embodiments, the target tissues inside the global coordinate system lead to direction of an automated positioning system that is directed based on the target tissues within the coordinate system. In some embodiments, a treatment plan is utilized in which beam energy and direction and duration of time for treatment is determined for a specific disease to be treated and/or structures to be avoided. In some embodiments, a fiducial marker is used to identify the location of the target tissues. In some embodiments, an eye is held with force and in alignment with the system. In some embodiments, the device automatically turns off with excessive movement outside of alignment along an axis of the eye. 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.
1. A method of treating an eye with radiotherapy, comprising:
emitting a first radiation beam, having a maximal energy, toward a target in an eye from a first x-ray source located within about 50 cm from the target;
the first x-ray source having an anode with a cross-section dimension less than about 5.5 mm;
the first radiation beam being configured such that a first beamspot at the target in the eye resulting from the first radiation 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 radiation beam, having the same maximal energy as the first radiation beam, emitted from a second x-ray source having a point-source anode; and
the second x-ray source being located at the same position relative to the target as the first x-ray source.
2. The method of claim 1 , wherein the first radiation beam has a maximal energy of less than about 500 keV.
3. 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 radiation beam for the selected treatment interval to apply a selected treatment radiation dose to the target in an eye.
4. 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 radiation beam when the eye is aligned with the treatment axis; and (c) discontinuing the emitting of the first radiation beam in the event that the eye is not aligned, within a determined threshold of alignment, with the treatment axis.
5. A method of treating an eye with radiotherapy, comprising:
emitting, from a first 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 first x-ray source having a maximal energy, an anode with a non-zero size, the first x-ray source being located within about 50 cm of the target 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 shape, a centroid, and at least one 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 of 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 a second x-ray source having a point-source anode and the same maximal energy as the first x-ray source, when the second x-ray source is located at the same position relative to the target area as the first x-ray source.
6. The method of claim 5 , wherein the first x-ray beam has a maximal energy of up to about 500 keV.
7. The method of claim 5 , wherein the first x-ray beam has a maximal energy of up to about 100 keV.
8. The method of claim 5 , 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.
9. The method of claim 5 , 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.
10. The method of claim 5 , wherein the first x-ray source has an anode with a size less than or equal to about 2.0 mm.
11. The method of claim 5 , wherein the first x-ray source has an anode with a size less than or equal to about 1.0 mm.
12. The method of claim 5 , wherein the first x-ray source has an anode with a size less than or equal to about 0.5 mm.
13. The method of claim 5 , wherein the first x-ray source is located less than or equal about 200 mm from the target area during the emitting.
14. The method of claim 5 , wherein the first x-ray source is located less than or equal about 150 mm from the target area during the emitting.
15. The method of claim 5 , wherein the first x-ray source is located less than or equal about 50 mm from the target area during the emitting.
16. The method of claim 5 , 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.
17. The method of claim 5 , 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.
18. The method of claim 5 , 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 10 mm from the target area.
19. The method of claim 5 , 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 5 , wherein the delimiting dimension of the first collimated x-ray beam is less than or equal to about 6 mm.
21. The method of claim 5 , wherein the delimiting dimension of the first collimated x-ray beam is less than or equal to about 2 mm.