Patent ID: 8848869

Claim:
Non-transitory machine-readable medium operable with an electronic computer, in treating a lesion on or adjacent the retina of an eye of a patient with an external-beam radiation device, to execute instructions effective to perform the steps comprising: (a) placing the eye in alignment with a known system axis in an external three-dimensional coordinate system, and measuring an axial length of the eye; (b) from a known position of the system axis and from the measured axial length, determining coordinates of the lesion to be treated in the external coordinate system; (c) directing a collimated x-ray radiation beam along a known beam axis in the external coordinate system at the lesion to be treated; (d) during said directing, tracking a position of the eye with respect to the known system axis, thus to track a position of the lesion to be treated in the external coordinate system; and (e) based on the known beam axis of the collimated beam in the external coordinate system, and the tracked position of the lesion to be treated in the external coordinate system, as determined at least in part by the tracked position of the eye, calculating a total radiation equivalent received at the lesion to be treated during the treatment.