Acoustic Surface Wave Position Measurement for Multileaf Collimators
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Solution Overview
Problem
Existing methods for determining the position of multileaf collimator leaves in medical radiation therapy are complex and involve undesirable radiation or require additional equipment, making them unsuitable for frequent, precise position measurements during treatment.
Innovation Solution
The use of acoustic surface waves, such as Rayleigh waves, to determine distance and position by generating a surface wave that reflects off marked points on the leaves, allowing for precise position measurement without the need for additional sensors or complex conversion processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position sensors or measuring apparatuses are installed on movable leaves, then position determination is possible, but device complexity and disruption increase
Solution Approach 1:
The patent replaces mechanical position sensors with acoustic surface wave-based measurement. A transmitter generates acoustic surface waves that propagate along the leaf surface, and the waves are detected at known positions to determine the leaf's position indirectly, eliminating the need for complex mechanical sensors on moving parts
Solution Approach 2:
The patent introduces acoustic surface waves as an intermediary medium between the transmitter and the movable leaf. Instead of directly measuring position with sensors on the leaf, the system uses the propagation characteristics of acoustic waves along the leaf surface as a mediator to infer position information
2Measurement precision
If additional light sources or cameras are used for position determination, then position information can be obtained, but device complexity and conversion complexity increase
Solution Approach 1:
The patent substitutes optical measurement systems (light sources, cameras) with acoustic surface wave-based measurement. The acoustic waves provide direct position information through propagation time and phase measurements, eliminating the need for complex optical-to-position conversion processes
3Measurement precision
If transmitters emit radiation for position determination, then position can be determined, but harmful radiation is emitted
Solution Approach 1:
The patent replaces radiation-based position determination with acoustic surface wave-based determination. The transmitter generates acoustic waves that propagate along the surface without emitting harmful radiation, while still enabling precise position measurement through acoustic wave propagation characteristics
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
This method provides a flexible, uncomplicated, and absolute position determination system that can measure multiple positions simultaneously, suitable for both flat and curved surfaces, reducing complexity and the need for referencing, and is applicable beyond medical engineering.
Implementation Method 1
acoustic surface waves may be used for distance and/or position determination
Implementation Method 2
the acoustic surface wave passes on the surface to a reflection point, from which the acoustic surface wave is reflected back to the apparatus
Data Source
AI summary
An apparatus for determining a distance includes a converter element that generates n acoustic surface wave, a surface that feeds over at least part of the acoustic surface wave to a surface having a reflection point, and a processor that determines a distance between the apparatus and the reflection point from the propagation time of the acoustic surface wave. The converter element registers the acoustic surface wave reflected at the reflection point.