Method and apparatus for radiation therapy
AssigneeWisconsin Alumni Research Foundation
InventorsStuart Swerdloff, Thomas R. Mackie, Timothy Holmes
Life of this patent
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Abstract
A radiation therapy apparatus includes a compensator having a plurality of leaves to divide the radiation beam into rays each of which may be effectively and individually attenuated over a range of attenuations by controlling the duty cycle of the leaves position between the open and closed states. An apparatus for controlling the compensator accounts for scattering of radiation through the deconvolution of a terma map and calculates a sinogram for controlling the compensator at a variety of angles about a patient using iterated forward and back projections efficiently calculated in frequency space.
Claims6
In a radiation therapy machine having a radiation source for producing a radiation beam directed toward a patient at a gantry angle, the beam including a plurality of adjacent rays dispersed within a beam plane, a compensator comprising:
- a plurality of radiation attenuating leaves;
- a rack positioned generally between the radiation source and the patient and having a plurality of adjacent sleeves for guiding the leaves across the beam plane between a closed state within the radiation beam, each leaf thus fully occluding one ray of the beam, and an open state outside of the radiation beam to allow unobstructed passage of the ray;
- motivation means for independently moving each leaf between the open and closed state;
- and
- timing means communicating with the motivation means for controlling the ratio of the period of time during which each leaf is in the closed state to the period during which each leaf is in the open state to control the average energy fluence of each ray of the beam.
Dependencies are inferred from the claim text.