US 9,808,652 B2
Collimator for radiotherapy apparatus
Virgil Willcut, Kirkwood, MO (US); Martin Broad, Bromley (GB); and David Anthony Roberts, East Ginstead (GB)
Assigned to Elekta AB (Publ), Stockholm (SE)
Filed by ELEKTA AB (PUBL), Stockholm (SE)
Filed on Dec. 29, 2016, as Appl. No. 15/394,193.
Application 15/394,193 is a continuation of application No. 14/495,137, filed on Sep. 24, 2014, granted, now 9,572,998.
Claims priority of application No. 1317016.2 (GB), filed on Sep. 25, 2013; and application No. 1411005.0 (GB), filed on Jun. 20, 2014.
Prior Publication US 2017/0106211 A1, Apr. 20, 2017
This patent is subject to a terminal disclaimer.
Int. Cl. A61N 5/10 (2006.01); G21K 1/04 (2006.01); G21K 1/02 (2006.01)
CPC A61N 5/1045 (2013.01) [A61N 5/1077 (2013.01); G21K 1/025 (2013.01); G21K 1/046 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A Collimator for a radiotherapy apparatus comprising:
a block of radiation-attenuating material for moving into and out of a beam of therapeutic radiation during delivery of the therapeutic radiation, the block having:
a top face and a bottom face, each transverse to a propagation direction of the beam and defining a depth direction extending from the top face to the bottom face; and
a front face, at least one main rear face, and at least two side faces, each face extending from the top face to the bottom face, the side faces extending from the front face to the at least one main rear face,
wherein the front face forms a leading edge when the block is moved into the beam, and
wherein the at least one main rear face is non-parallel to the front face, and
wherein a material is disposed against the at least one main rear face of the block.
 
14. A radiotherapy apparatus, comprising:
a radiation beam emitted by the beam source through an aperture;
a multi-leaf collimator with leaves moveable across the aperture, and having a range of movement adequate to transport a tip of each leaf from one side of the aperture to the other side; and
a block collimator having:
a depth in a propagation direction of the radiation beam;
a front face defining a leading edge of the block when the block moves into the beam; and
at least one main rear face defining a trailing edge when the block moves into the beam,
wherein the at least one main rear face is non-parallel to the front face and the block collimator is moveable across the aperture in a direction transverse to the movement of the leaves.
 
17. A method of operating a radiotherapy apparatus, the radiotherapy apparatus including a multi-leaf collimator with leaves moveable across an aperture through which a radiation beam is emitted, and a block collimator moveable across the aperture in a direction transverse to the movement of the leaves during delivery of the radiation, the method comprising:
controlling movement of the leaves or the block collimator so as to match the leaves to the profile of a rear face of the block collimator extending in the direction of the radiation beam.