Dual-Frequency Spherical-Confocal-Split Array for Focused Ultrasound
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Solution Overview
Problem
Conventional focused ultrasound treatments using single-frequency phased arrays are inefficient due to small focal regions and complex control systems, requiring extended treatment times for larger tumors.
Innovation Solution
A spherical-confocal-split array with dual frequency fundamental and harmonic superimposition is used, where half of the array elements operate at a lower MHz frequency and the other half at a higher MHz frequency, with phase and amplitude control to generate split foci within the focal region, enhancing cavitation and thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-frequency phased array is used for focused ultrasound treatment, then the control system is relatively simple, but the focal region volume is small and treatment time is long
Solution Approach 1:
The array elements are divided into two groups operating at different frequencies (fundamental frequency f0 and harmonic frequency 2f0). This segmentation allows simultaneous generation of multiple foci through frequency-based spatial division, expanding the effective treatment volume without requiring a larger number of array elements or more complex control systems.
Solution Approach 2:
The patent changes the frequency parameter by using dual-frequency (fundamental and harmonic) operation instead of single-frequency operation. This parameter change enables the system to create split foci with different spatial distributions, effectively increasing the focal region volume and treatment efficiency while maintaining the same array configuration.
2Volume of stationary object
If dual-frequency fundamental and harmonic superimposition is used, then the focal region volume is significantly expanded, but the array element frequency distribution becomes complex
Solution Approach 1:
Array elements are segmented into two distinct groups: one group operates at the fundamental frequency f0 and the other at the harmonic frequency 2f0. This clear segmentation simplifies the frequency distribution strategy compared to using many different frequencies, as only two frequency values need to be managed across the array.
Solution Approach 2:
The patent merges the fundamental frequency and harmonic frequency operations within the same array system. By combining these two frequency components and controlling their superimposition, the system achieves expanded focal volume without requiring separate systems for each frequency, thus managing complexity while achieving the volume expansion goal.
3Volume of stationary object
If more array elements are used to increase focal region size, then the treatment volume is expanded, but the device complexity and driving channel requirements increase
Solution Approach 1:
Instead of increasing the number of array elements, the patent changes the operating frequency parameter to utilize dual-frequency operation. This allows the same number of array elements to produce expanded treatment volume through frequency-based spatial modulation, avoiding the need for additional elements and driving channels.
Solution Approach 2:
The patent introduces a frequency dimension (using both fundamental and harmonic frequencies) to achieve volume expansion, rather than only relying on spatial arrangement of array elements. This dimensional change in the parameter space allows volume expansion without proportionally increasing the number of physical elements required.
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 approach significantly expands the focal region volume, increases cavitation activity, and enhances thermal efficiency, reducing treatment time by generating split foci with peak intensities higher than the sum of individual frequencies, thus improving HIFU treatment efficiency.
Implementation Method 1
A spherical-confocal-split array with dual frequency fundamental and harmonic superimposition is used, wherein half of the array elements operate at a lower MHz frequency and the other half at a higher MHz frequency
Implementation Method 2
each of array element beams only superimposes inside a focal region... the superimposition of two frequency pressures results in split foci along beam axial within confocal region
Implementation Method 3
increases cavitation activity... effectively using cavitation thermal mechanism
Implementation Method 4
thermal ablation using ultrasound thermal mechanism... enhances thermal efficiency
Data Source
AI summary
A spherical-confocal-split array with dual frequency of fundamental and harmonic superimposition includes: array elements which are spherically confocal, whose quantity is an even number, wherein a half of the array elements operate with a lower frequency, and the other half of the array elements operate with a higher frequency; both the lower frequency and the higher frequency are MHz high-frequencies; each of the array elements corresponds to a frequency drive; array element beams don't superimpose outside the focal region; each of the array elements is connected to a channel amplifier (3) through corresponding impedance matching (2); and a multi-channel waveform controller (4) is connected to the channel amplifier (3) for controlling amplitudes and phases of all channels. The dual-frequency spherical sectorial split array is able to generate split multi-foci of the focal plane with the dual frequencies; and control strong interference of transient cavitation clouds at the adjacent foci.