HEAVY ION RADIATION THERAPY SYSTEM WITH STAIR-STEP MODULATION
First Claim
Patent Images
1. An therapeutic radiation modulator comprising:
- an inlet receiving a fan beam of radiation comprised of adjacent beamlets traveling along axes, the fan beam having a cross-sectional area whose greatest dimension extends along a plane;
a set of arrays of modulation elements, the arrays positioned side-by-side along the plane within the cross-sectional area, the modulation elements of each array aligned with a different beamlets, each modulation element movable between at least one extended position within the cross-sectional area and a retracted position outside of the cross-sectional area;
a set of actuators communicating with each modulation element to independently actuate the modulation elements to move them between at least two discrete positions, one position out of the fan beam and at least one position in the fan beam; and
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.
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Abstract
A system for modulating a fan beam for radiation treatment employs shutters that may move rapidly into and out of different beamlets of a fan beam, the shutters having a systematic weighting so that a limited number of shutters may obtain a far greater number of regularly spaced energy reductions.
62 Citations
17 Claims
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1. An therapeutic radiation modulator comprising:
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an inlet receiving a fan beam of radiation comprised of adjacent beamlets traveling along axes, the fan beam having a cross-sectional area whose greatest dimension extends along a plane; a set of arrays of modulation elements, the arrays positioned side-by-side along the plane within the cross-sectional area, the modulation elements of each array aligned with a different beamlets, each modulation element movable between at least one extended position within the cross-sectional area and a retracted position outside of the cross-sectional area; a set of actuators communicating with each modulation element to independently actuate the modulation elements to move them between at least two discrete positions, one position out of the fan beam and at least one position in the fan beam; and 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of modulating an ion beam comprising:
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(a) receiving a beam of ions having a cross-sectional area and traveling along an axis; (b) positioning a set of arrays of modulation elements so that the modulation elements of each array are aligned along the axis, wherein each modulation element is movable between an extended position within the cross-sectional area and a retracted position outside of the cross-sectional area, and so that the arrays of modulation elements are positioned adjacent to each other perpendicular to the axis over a continuous portion of the cross-sectional area; (c) controlling a set of actuators communicating with each modulation element to independently actuate the modulation elements to move them from the retracted position to the extended position and de-actuate the modulation elements to move the modulation elements from the extended position to the retracted position so that a series of regular increments of effective thickness of modulation elements within the beam can be provided by selection of different combinations of the modulation elements for actuation. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification