Leaf-end configuration for multileaf collimator
First Claim
1. A multileaf collimator for use in a radiation system including a radiation source, said collimator having a plurality of elongated leaves, each leaf being movable in a longitudinal direction, and each terminating in a leaf end extending in a direction generally transverse to said longitudinal direction, said leaf end defining a central portion having one of a curved and polygonal configuration and a generally flat end portion.
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Accused Products
Abstract
A multileaf collimator for use in therapeutic radiology treatment systems for producing irregular shaped radiation fields in order to shield normal tissue or critical organs. A multileaf collimator following the present invention includes leaves designed such that the collimator exhibits penumbra which is minimized and generally uniform for positions that are equidistant from the central axis of the radiation field. The shape of each leaf end includes an asymmetric central portion and a flat portion on either side of the central portion. The central portion is designed such that geometric penumbra and transmission penumbra are equalized. The flat portions on either side of the central portion are coincident with a tangent drawn from the edge of the radiation source to a reference plane when the leaf is in the fully retracted or fully extended positions.
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Citations
30 Claims
- 1. A multileaf collimator for use in a radiation system including a radiation source, said collimator having a plurality of elongated leaves, each leaf being movable in a longitudinal direction, and each terminating in a leaf end extending in a direction generally transverse to said longitudinal direction, said leaf end defining a central portion having one of a curved and polygonal configuration and a generally flat end portion.
- 10. A multileaf collimator for use in a radiation system having a radiation source, said collimator having a plurality of elongated leaves, each leaf being movable in a longitudinal direction and terminating in a leaf end extending in a direction generally transverse to said longitudinal direction, each leaf end being symmetric about a point offset distally from the radiation source with respect to a centerline of the respective elongated leaf.
- 16. A multi-leaf collimator for use with a ray source defining a source axis, said collimator comprising a plurality of longitudinally elongated leaves arranged in a side-by-side array, each leaf terminating in a leading leaf end, each leaf being movable transversely with respect to a central axis generally parallel to said source axis, between a fully retracted mode and a fully extended mode, each leading end defining first and second generally flat zones separated by an intermediate zone generally continuous with said flat zones, one of said flat zones substantially coinciding with a first tangent line extending from a position on said central axis to said leading leaf end with the corresponding leaf in said fully retracted mode, the other of said flat zones substantially coinciding with a second tangent line extending from said central axis to said leaf end with said corresponding leaf in said fully extended mode.
- 20. In a radiation therapy system including a ray source for producing a radiation field, the improvement comprising a multileaf collimator having a plurality of elongated leaves, each leaf being movable in a longitudinal direction to define a treatment field out of said radiation field which is variable in size and form dependent on the position of said leaves, each leaf including a leaf end extending in a direction transverse to said longitudinal direction, said leaf end having a central portion being symmetric about a point offset from a longitudinal centerline of said respective leaf.
- 28. A leaf for use in a multileaf collimator, said leaf comprising an elongated body and a leaf end, said leaf end comprising a first planar end portion and a second planar end portion and a central portion having one of a curved and polygonal configuration, said central portion disposed between said first and second planar portions such that said first planar end portion and said second planar end portion are not colinear.
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30. A radiation therapy system comprising an x-ray source for producing a therapeutic radiation field having a central axis, a multileaf collimator having a plurality of elongated leaves movable about a central axis parallel to said central axis of said x-ray source to define said radiation field, each leaf being independently movable from a fully retracted position disposed on a first side of said central axis to a fully extended position extending beyond said central axis, each said leaf including a leaf end extending in a direction generally parallel to said central axis and comprising:
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a central non-linear portion defined by a simple radius symmetric about a point offset distally from the longitudinal axis of the leaf; a first planar end portion disposed proximate said x-ray source and coinciding with a tangent extending from the edge of said x-ray source to said leaf end when said leaf end is disposed at said fully extended position; and a second planar end portion disposed distal from said x-ray source and coinciding with a tangent extending from the edge of said x-ray source to said leaf end when said leaf end is disposed at said fully retracted position.
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Specification