HIFU Transducer Phase Control for Near Field Overlap Heating
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Solution Overview
Problem
In magnetic resonance guided high intensity focused ultrasound treatments, the overlapping near field regions of multiple sonication points can lead to unwanted tissue heating due to cumulative ultrasound energy deposition, necessitating delays between sonications to avoid overheating.
Innovation Solution
A medical apparatus and computer program product that control the phase and amplitude of multiple transducer elements to reduce ultrasonic energy deposition in overlapping near field regions by determining sonication paths and transducer control commands, allowing for sequential sonication of multiple points without overheating, using geometric models and thermal property maps to optimize energy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple sonication points are treated sequentially with a focused ultrasonic transducer, then the treatment coverage is improved, but the overlapping near field regions cause cumulative heating that requires delays between sonications
Solution Approach 1:
The patent applies local quality by differentiating the treatment approach for different spatial regions. Transducer elements are selectively controlled based on their specific contribution to near field overlap regions versus non-overlapping regions. Elements contributing to overlapping near field regions have their amplitude reduced or phase adjusted, while elements contributing only to non-overlapping regions maintain full treatment intensity, allowing continuous treatment without delays.
Solution Approach 2:
The patent changes the parameters (amplitude and phase) of individual transducer elements dynamically based on their spatial contribution to overlapping regions. By adjusting these parameters, the system reduces energy deposition in overlapping near field regions while maintaining effective treatment at sonication points, eliminating the need for treatment delays.
2Temperature
If delays are introduced between sonicating multiple sonication points to avoid overheating, then the near field temperature is controlled, but the treatment time increases
Solution Approach 1:
The patent performs preliminary action by calculating the near field overlap regions and determining adjusted transducer control commands before treatment begins. The system uses a geometric model of the transducer and sonication points to pre-determine which elements need amplitude or phase adjustments, allowing continuous treatment without interruptions or delays while maintaining temperature control.
3Temperature
If the amplitude of transducer elements is reduced in overlapping regions, then the cumulative heating is minimized, but the energy delivery to target tissue is reduced
Solution Approach 1:
The patent applies local quality by selectively adjusting only those transducer elements whose ultrasound paths contribute to overlapping near field regions. Elements with paths that do not overlap maintain full amplitude for effective treatment, while only the specific elements causing cumulative heating have reduced amplitude or adjusted phase, preserving overall treatment efficacy while controlling temperature.
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 minimizes thermal dose in the near field regions, reducing waiting times between sonications and enhancing treatment efficiency by preventing excessive heating, thus allowing for more rapid and controlled tissue treatment.
Implementation Method 1
Ultrasonic waves are transmitted as high energy mechanical vibrations. These vibrations induce tissue heating as they are damped
Implementation Method 2
a focused ultrasonic transducer can be used to focus the ultrasound on a particular treatment or target volume
Data Source
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AI summary
The invention provides for a medical apparatus (200, 400, 500) comprising a high intensity focused ultrasound system (206). Machine executable instructions (260, 262, 264, 266, 408, 526) in a memory (250) cause a processor (244) to: receive (100) location data (252) descriptive of multiple sonication points (224, 226, 228, 230); determine (102) a sonication path (254) for each of the multiple sonication points using a geometric transducer element model (262);detect (104) an overlap region (256, 306) using the sonication path in the near field region;determine (106) transducer control commands (258) using the overlap region, wherein the transducer commands are operable to control the multiple transducer elements to reduce the deposition of ultrasonic energy in the overlap region during sonication of the two or more sonication points; and control (108)the high intensity focused ultrasound system using the transducer control commands.