Elongated Hydrophone Array for Acoustic Field Characterization
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Solution Overview
Problem
Current methods for characterizing therapeutic ultrasound fields are inadequate due to challenges in measuring high-pressure amplitudes and complex three-dimensional structures, leading to difficulties in accurately determining the acoustic field delivered to patients, which hinders the broader clinical acceptance of High Intensity Focused Ultrasound (HIFU) treatments.
Innovation Solution
An array-based ultrasound system that captures two-dimensional distributions of acoustic beam characteristics, including magnitude and phase, using elongated elements with specific aspect ratios to measure acoustic fields without preamplification, allowing for the reconstruction of three-dimensional acoustic fields and calibration of ultrasound sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard point-by-point hydrophone measurements are used to characterize acoustic fields, then measurement accuracy can be maintained, but the number of measurements required becomes prohibitively large for large treatment volumes and multiple operation modes
Solution Approach 1:
The patent divides the measurement task into two segments: first capturing a two-dimensional pressure distribution map using a hydrophone array, then using acoustic holography mathematics to calculate the three-dimensional acoustic field from this segmented data set, avoiding the need for exhaustive point-by-point measurements throughout the entire treatment volume
Solution Approach 2:
The patent transitions from three-dimensional spatial measurements to a two-dimensional pressure distribution measurement plane. By measuring pressure across a two-dimensional array and applying acoustic holography calculations, the system reconstructs the full three-dimensional acoustic field information without requiring direct three-dimensional measurements at every point
2Measurement precision
If high pressure amplitudes are measured directly with hydrophones, then accurate acoustic field data can be obtained, but the high pressures can damage hydrophones and require large measurement bandwidths
Solution Approach 1:
The patent measures pressure at a single time point (partial action in time) rather than continuously tracking the full pressure waveform, and uses the spatial distribution of this partial measurement combined with acoustic holography to reconstruct the complete three-dimensional acoustic field, avoiding the need for hydrophones to withstand full high-pressure waveforms
Solution Approach 2:
The patent introduces acoustic holography calculations as an intermediary process between the two-dimensional pressure measurement and the three-dimensional acoustic field characterization. This mathematical intermediary allows accurate reconstruction of full acoustic field data without directly exposing measurement devices to damaging high-pressure conditions
3Productivity
If acoustic holography is used to reconstruct three-dimensional acoustic fields from two-dimensional measurements, then measurement time can be reduced, but the complexity of obtaining reliable results increases
Solution Approach 1:
The patent performs preliminary action by capturing the complete two-dimensional pressure distribution map at an early stage, which serves as sufficient boundary conditions for the acoustic holography calculations. This preliminary measurement setup, when combined with the mathematical reconstruction, enables rapid three-dimensional field characterization without requiring complex real-time measurements
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
Enables accurate characterization and calibration of ultrasound sources, improving the precision of HIFU treatments by providing reliable measurements of acoustic fields, thereby enhancing treatment efficacy and safety.
Implementation Method 1
ultrasound consists of waves, it possesses several basic features of wave physics
Implementation Method 2
amplitude and phase can often be measured directly with a pressure sensor
Implementation Method 3
it is possible to reproduce a three-dimensional field from a two-dimensional distribution of the wave amplitude and phase along some surface transverse to the wave propagation. This principle is widely used in optics, and the corresponding process is termed 'holography.' A similar approach is possible in acoustics.
Data Source
AI summary
The present technology relates generally to receiving arrays to measure a characteristic of an acoustic beam and associated systems and methods. The receiving arrays can include elongated elements having at least one dimension, such as a length, that is larger than a width of an emitted acoustic beam and another dimension, such as a width, that is smaller than half of a characteristic wavelength of an ultrasound wave. The elongated elements can be configured to capture waveform measurements of the beam based on a characteristic of the emitted acoustic beam as the acoustic beam crosses a plane of the array, such as a transverse plane. The methods include measuring at least one characteristic of an ultrasound source using an array-based acoustic holography system and defining a measured hologram at the array surface based, at least in part, on the waveform measurements. The measured hologram can be processed to reconstruct a characteristic of the ultrasound source. The ultrasound source can be calibrated and/or re-calibrated based on the characteristic.