Ultrasound Grating Lobe Control via Phased Array
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Solution Overview
Problem
Current ultrasound transducers are limited in their ability to treat large volumes of tissue effectively due to small focal zones and the creation of secondary off-axis foci, or 'grating lobes,' which reduce the efficacy of the ultrasound beam, especially in confined spaces.
Innovation Solution
A system that alters the phasing of transducer elements on a linear ultrasound array to control the positions of grating lobes, allowing for multiple insonifications to create multiple foci that cover a larger volume, thereby increasing ablation depth and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single focused transducer element or small array is used, then treatment selectivity is improved, but the ability to treat large volumes of tissue deteriorates
Solution Approach 1:
The invention segments the treatment volume into multiple sub-volumes, each targeted by a specific grating lobe focus. By dividing the large target tissue into regions that can be sequentially addressed by different grating lobes, the system achieves both selectivity (treating specific regions) and completeness (covering the entire large volume).
Solution Approach 2:
The invention transitions from a single focal point in one dimension to multiple foci distributed across three-dimensional space. By utilizing the spatial distribution of grating lobes in multiple dimensions, the system expands the effective treatment volume while maintaining precise control over where energy is deposited.
2Volume of stationary object
If a transducer array with larger aperture is used, then treatable tissue volume is improved, but grating lobes are created that reduce beam efficacy
Solution Approach 1:
The invention converts the harmful grating lobes, which were traditionally considered unwanted artifacts reducing beam efficacy, into beneficial multiple foci that expand treatable volume. By intentionally utilizing and controlling the grating lobe positions, the system transforms what was a reliability issue into a feature that enhances treatment capability.
Solution Approach 2:
The invention changes the operational parameters of the transducer array by applying specific phase shifts to individual elements. By modifying the phase parameters, the system controls the positions and intensities of grating lobes, transforming them from harmful off-axis foci into useful treatment zones with predictable and controllable energy distribution.
3Adaptability or versatility
If electronic focusing with phase delays is used, then movement of treatment location is enabled, but grating lobes are created that draw energy from main focal lobe
Solution Approach 1:
The invention implements dynamic control of grating lobe positions through real-time adjustment of phase shifts. By making the grating lobe configuration adaptive and changeable, the system can optimize energy distribution for different treatment scenarios, moving grating lobes to desired locations while minimizing energy loss from the main focal lobe.
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 more efficient ablation of large target tissues with greater ablation depth and uniform heating patterns, overcoming the limitations of single focal points and grating lobes, while maintaining selectivity and sparing critical structures.
Implementation Method 1
Electronic focusing involves the use of phase delays and wave interference to achieve constructive interference at the target tissue
Implementation Method 2
Electronic focusing involves the use of phase delays and wave interference to achieve constructive interference at the target tissue
Implementation Method 3
HIFU pulses induce changes in tissue state through thermal effects (e.g., induced hyperthermia) and mechanical effects
Implementation Method 4
The absorption of the ultrasonic energy at the focus induces a sudden temperature rise of tissue, which causes ablation of the target volume of cells in the focal region
Implementation Method 5
HIFU pulses induce changes in tissue state through thermal effects (e.g., induced hyperthermia) and mechanical effects (e.g., induced cavitation)
Data Source
AI summary
A system and method for medical treatment of tissue using ultrasound. The system comprises a probe having an array of transducer elements, an ultrasound waveform generator adapted to generate at least one electrical ultrasound signal, and a plurality of phase controls, each coupled to the ultrasound waveform generator and adapted to generate from the electrical ultrasound signal a phase-shifted drive signal that is coupled to an associated transducer element. The drive signal is effective to control grating lobe foci emitted by the array. The method employs the system.