Abstract: A method and system for gating therapeutic or diagnostic energy to a tissue volume of a medical patient during a selected portion of the patient's respiratory cycle, to thereby diminish inaccuracies in the assumed spatial position of the tissue volume arising from displacements induced by the patient's respiration. The gases flowing to and from the patient's lungs are monitored to provide quasi-continuous measurements as a function of time, for any selected subset of (a) flow rate, (b) pressure, (c) patient lung volume and (d) carbon dioxide concentration. The measurements are utilized to trigger the time period during which the energy is gated on, at the beginning of the selected portion of the respiration cycle; and the time period during which the energy is gated on, is terminated at the end of the selected portion of the respiration cycle.

Abstract: A method and system for gating therapeutic or diagnostic energy to a tissue volume of a medical patient during a selected portion of the patient's respiratory cycle, to thereby diminish inaccuracies in the assumed spatial position of the tissue volume arising from displacements induced by the patient's respiration. The gases flowing to and from the patient's lungs are monitored to provide quasi-continuous measurements as a function of time, of (a) flow rate, (b) pressure, (c) patient lung volume and (d) carbon dioxide concentration. The measurements are utilized to trigger the time period during which the energy is gated on, at the beginning of the selected portion of the respiration cycle; and the time period during which the energy is gated on, is terminated at the end of the selected portion of the respiration cycle.

Abstract: A differential scatter-air ratio calculation procedure is utilized to calculate scatter contribution which when combined with primary radiation yields patient dose. The lengthy polar coordinate integration of the prior art is replaced with a rectangular coordinate integration which to an extent can be performed outside an integration loop. Beam characteristics are entered into a one dimensional matrix BWP. A second matrix RSAR includes the differential scatter air ratio for incremental regions within the patient at a certain depth and radial distance from a scatter calculation point. During a rectangular coordinate integration, a two dimensional coordinate within a patient plane determines an offset into both the one dimensional beam characteristic matrix BWP and the differential scatter-air ratio matrix RSAR. Then values are multiplied to produce a scatter contribution from the incremental region.