Improvements in or relating to multi-leaf collimators

Abstract

A multi-leaf collimator for a radiotherapy apparatus comprises at least one array of laterally-spaced elongate leaves, each leaf being driven by an associated motor connected to the leaf via a drive means so as to extend or retract the leaf in its longitudinal direction, the drive means comprising a sub- frame on which at least a subset of the motors are mounted, the sub-frame being mounted at a location spaced from the leaf array in a direction transverse to the lateral and longitudinal directions, and including a plurality of leadscrews disposed longitudinally, each being driven by a motor and being operatively connected to a leaf thereby to drive that leaf. This greater space efficiency, and allows the drive system to be modular. A plurality of the motors mounted on the subframe can be mounted at a first longitudinal end, and the remainder of the motors mounted on the subframe are mounted at a second, opposing, longitudinal end. Those leadscrews not at an edge of the array are preferably neighboured on either lateral side by one leadscrew driven by a motor mounted at the same longitudinal end and a second leadscrew driven by a motor mounted at the opposite longitudinal end. This results in the motors being arranged in pairs with a gap between which provides space for mounting the motors. The pairs of motors can be arranged one above the other to allow the necessary clearances, meaning that the leadscrews will be mounted in the subframe at one of two spacings from the leaf, with laterally neighbouring leadscrews being mounted at alternating spacings. The leadscrews can be mounted within a bore in the subframe. Alternate leaves can be driven by a corresponding lower subframe.

Description

technical field [0001] The present invention relates to multi-leaf collimators. Background technique [0002] Radiation therapy equipment involves the generation of beams of ionizing radiation, usually X-rays or electron beams or other subatomic particles. The radiation beam is aimed at the patient's cancerous area and adversely affects the tumor cells, thereby alleviating the patient's symptoms. Generally, it is preferred to define the radiation beam so that the dose is maximized in the patient's tumor cells and minimized in healthy cells, as this improves the efficiency of the treatment and reduces the side effects experienced by the patient. Various methods of doing this have been developed. [0003] A major component in defining the radiation dose is the so-called "multi-leaf collimator" (MLC). This is a collimator consisting of a large number of elongated thin leaves mounted side by side in an array. Each blade is movable longitudinally in order to extend its tip in...

AI Technical Summary

Problems solved by technology

[0017] Accordingly, the present invention seeks to provide a small MLC actuator that solves many of the problems associated with conventional lead screw systems, capable of actuating a greater amount of blade potential

Shaped design also improves maintenance issues by providing complete removal of the drive system from the blade set

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