Patent ID: 8269196
Filing Date: 2012-09-18
Classification: A61N

Abstract:
1. A therapeutic radiation modulator comprising: an inlet receiving a fan beam of radiation movable over a range of angular positions about a patient, and comprised of adjacent beamlets traveling along axes, the fan beam having a cross-sectional area perpendicular to a propagation of the radiation whose greatest dimension extends along a plane and whose least dimension defines a fan beam thickness; a set of arrays of modulation elements, the arrays positioned side-by-side along the plane, the modulation elements of each array aligned with a different beamlet, each modulation element movable along the fan beam width between an extended position extending fully through the fan beam width and a retracted position outside of the fan beam; a set of bistable actuators communicating with each modulation element to independently actuate the modulation elements to move them only to the extended or retracted positions at each discrete angular position during movement of the fan beam over the range of angular positions about the patient; a control system communicating with each bistable actuator to independently activate the bistable actuators; wherein different modulation elements provide predetermined effective thicknesses so that a series of regular increments of energy reduction can be provided in different beamlets of the fan beam by selection of different combinations of the modulation elements for actuation; and wherein the modulation elements of each array provide a sequence of increasing effective thicknesses combinable to provide the regular increments of energy attenuation.