Slit-Enabled Photoacoustic Tomography Elevation Resolution
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Solution Overview
Problem
Conventional linear transducer arrays in photoacoustic tomography have limited three-dimensional imaging capability due to poor elevation resolution, which is not effectively addressed by existing methods that often require complex scanning geometries and prolonged scanning times.
Innovation Solution
A photoacoustic tomography device and method that incorporates a slit formed by blades positioned parallel to the transducer's receiving aperture, allowing for improved elevation resolution by diffracting photoacoustic waves and enhancing the receiving aperture, without altering the scanning geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional linear transducer arrays are used in photoacoustic tomography, then the device structure is simple and scanning is fast, but the elevation resolution is poor
Solution Approach 1:
A slit structure is introduced as an intermediary component between the sample and the linear transducer array. The slit diffracts photoacoustic waves in the elevation direction, effectively mediating the wave propagation to improve elevation resolution without requiring complex scanning geometries or multiple transducer arrays
Solution Approach 2:
The acoustic impedance of the blade material is specifically engineered to be at least two times greater than or less than that of water, creating strong acoustic contrast at the slit boundaries. This parameter change enables effective diffraction of photoacoustic waves while maintaining a simple linear array configuration
2Measurement precision
If linear transducer arrays with acoustic lens are used, then axial and lateral resolutions are good, but elevation receiving aperture is limited
Solution Approach 1:
The slit structure manipulates wave propagation in the elevation dimension by introducing diffraction effects. By controlling the acoustic impedance contrast at the slit boundaries, the system effectively extends the elevation receiving aperture without physically enlarging the transducer array area
3Measurement precision
If complex scanning methods are used to improve elevation resolution, then elevation resolution improves, but scanning time increases
Solution Approach 1:
The invention extracts the elevation resolution enhancement function from the scanning mechanism itself and transfers it to a static slit structure. This separation allows the linear array to maintain its fast scanning capability while the slit continuously provides elevation resolution improvement through diffraction, eliminating the need for prolonged scanning times
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
The slit-enabled approach significantly improves elevation resolution by ten times while maintaining high imaging speed, providing better signal-to-noise ratio and adapting easily to existing linear-array devices, without the need for complex scanning modifications.
Implementation Method 1
a laser positioned to produce acoustic waves in a sample
Implementation Method 2
improved elevation resolution by diffracting photoacoustic waves
Implementation Method 3
an acoustic absorber affixed to each of the one or more blades along a surface proximal to the transducer
Data Source
AI summary
Devices and methods for photoacoustic tomography are disclosed herein. One exemplary photoacoustic tomography device uses a laser to produce acoustic waves in a sample. A transducer receives the acoustic waves through a slit formed by one or more blades positioned substantially parallel to the receiving aperture of the transducer. An acoustic absorber is affixed to each of the one or more blades along a surface proximal to the transducer. A processor acquires acoustic data and reconstructs photoacoustic tomographic images based on the acquired data. Reconstructing the image involves setting reconstruction parameters, defining a reconstruction area, reconstruction position, and pixel size, and calculating an acoustic travelling path for the sample to each transducer element. The acoustic travelling paths are saved into a three-dimensional array.