Patent ID: 8442185

Claim:
A method of treating an eye with radiotherapy, comprising: applying an ocular stabilizing device to the eye that limits or prevents eye movement during a selected treatment interval; emitting a first x-ray beam, having a maximal energy of less than about 500 keV, toward a target in an eye from a first x-ray source located at a first position relative to the target, the first x-ray source having an anode with a non-zero size, the first position being within about 50 cm of the target and spaced away from the eye; 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, theoretical beamspot at the target; the second, theoretical beamspot resulting from a second, theoretical x-ray beam, having the same maximal energy as the first x-ray beam, emitted from a second, theoretical x-ray source, at the first position, having an idealized point-source anode; and moving the eye, using the ocular stabilizing device, relative to the first x-ray beam.