Multi-Leaf Collimator Leaf Positioning via Optical Signal Detection
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Solution Overview
Problem
Existing leaf positioning methods for multi-leaf collimators in radiotherapy equipment suffer from low measurement accuracy due to installation tolerance in transmission mechanisms and are prone to errors, especially when mechanical failures occur, affecting the precision of radiation field formation.
Innovation Solution
A leaf positioning device with a matrix of positioning signal transmitters and receivers, connected to a positioning device that includes a receiving unit, signal-shaping circuit, and encoder, allowing direct measurement of leaf positions and precise control of leaf movement using a screw rod, thereby improving positional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If motor encoder is used to measure leaf position through motor rotation, then the positioning system is simple to implement, but installation tolerance in transmission mechanisms causes measurement error
Solution Approach 1:
The patent replaces the mechanical measurement system (motor encoder measuring motor rotation) with an optical measurement system (positioning signal transmitters and receivers directly measuring leaf position). This substitution eliminates the transmission mechanism tolerance problem by directly optically detecting the leaf's actual position rather than inferring it from motor rotation through mechanical transmissions.
Solution Approach 2:
The patent introduces positioning signal transmitters and receivers as intermediary components that directly interact with the leaf to measure its position. These intermediaries provide a direct measurement path between the leaf and the measurement system, bypassing the problematic mechanical transmission chain between motor and leaf.
2Device complexity
If motor encoder based positioning is used, then the system structure is simple, but the actual leaf position cannot be reflected when screw rod slips
Solution Approach 1:
The patent replaces the indirect mechanical inference method with direct optical measurement. The positioning signal transmitters and receivers directly detect the leaf's actual position, providing reliable feedback even when mechanical components like the screw rod slip or fail, since the measurement is independent of the mechanical transmission chain.
Solution Approach 2:
The patent implements direct feedback from the leaf's actual position through positioning signal transmitters and receivers. This feedback mechanism continuously monitors the true position and provides real-time information to the control system, enabling reliable position detection regardless of mechanical transmission issues.
3Ease of manufacture
If transmission mechanisms are used to connect motor and leaves, then the positioning system is easy to implement, but installation tolerance causes error between actual and measured positions
Solution Approach 1:
The patent eliminates the mechanical transmission chain (coupling and screw rod) that introduces tolerance errors by substituting it with an optical measurement system. The positioning signal transmitters and receivers directly measure leaf position without relying on mechanical transmissions, thereby achieving high positioning accuracy while maintaining implementation simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the accuracy of leaf positioning, reducing errors and mechanical failures, and improving the precision of radiation field formation in radiotherapy, particularly for high-precision methods like intensity modulated radiation therapy.
Implementation Method 1
a plurality of positioning signal transmitters configured to transmit positioning signals to a plurality of positioning signal receivers
Data Source
AI summary
Disclosed a leaf positioning device (100) for a multi-leaf collimator, comprising: a plurality of positioning signal transmitters which are in the leaf guide rail box, wherein the plurality of positioning signal transmitters are arranged opposite to a first end surface of leaves of the multi-leaf collimator; a plurality of positioning signal receivers which are in the leaf guide rail box and corresponding to the plurality of positioning signal transmitters, wherein the plurality of positioning signal receivers are arranged opposite to a second end surface of the leaves of the multi-leaf collimator; wherein, the plurality of positioning signal transmitters are configured to transmit positioning signals to the plurality of positioning signal receivers, and the plurality of positioning signal receivers are configured to generate output signals according to the positioning signals; a positioning device which is connected to each of the plurality of positioning signal receivers, wherein the positioning device is configured to receive the output signals sent out by each of the plurality of positioning signal receivers, and positions the leaves of the multi-leaf collimator according to the output signals.