RF Phased Array Pulse Design for Targeted Hyperthermia
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Solution Overview
Problem
Current methods for tissue treatment, such as ionizing radiation, face challenges in minimizing damage to healthy tissues and monitoring dose distribution, while RF-based hyperthermia treatments struggle with energy deposition in non-target regions due to skull absorption in non-invasive brain treatments.
Innovation Solution
The use of RF phased arrays in MRI systems to design parallel transmission RF pulses that maximize energy deposition in target regions while minimizing deposition in non-target regions, using SAR matrices and optimization processes to control local and global SAR within hardware constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ionizing radiation is used for tissue treatment, then cell killing capability is improved, but damage to healthy tissues increases
Solution Approach 1:
The patent applies local quality by using multiple RF transmit channels with independently controlled amplitude and phase to create spatially selective energy deposition. Each channel contributes differently to the target region, allowing precise control of where energy is deposited (target vs. healthy tissue) through constructive and destructive interference patterns in the electromagnetic field distribution.
Solution Approach 2:
The patent transitions from conventional single-channel RF heating to multi-channel parallel transmission, adding the dimension of spatial control through phase and amplitude modulation. This enables three-dimensional focusing of RF energy by controlling the phase relationships across multiple transmit elements, creating focused heating zones that were not achievable with single-channel systems.
2Temperature
If ultrasound power is increased to achieve significant heating inside the brain, then heating capability is improved, but heating of skull and skin increases
Solution Approach 1:
The patent applies local quality by using multiple RF transmit channels with independently controlled amplitude and phase to create spatially selective energy deposition. Each channel contributes differently to the target region, allowing precise control of where energy is deposited (target vs. healthy tissue) through constructive and destructive interference patterns in the electromagnetic field distribution.
Solution Approach 2:
The patent uses SAR matrices as an intermediary tool to model and predict energy deposition patterns before actual treatment. These pre-computed matrices allow the system to evaluate different transmit channel combinations and select those that achieve target heating while minimizing exposure to surrounding tissues, acting as a planning mediator between treatment goals and physical constraints.
3Manufacturing precision
If RF phased arrays with multiple channels are used for parallel transmission, then energy deposition control is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-computing SAR matrices for each transmit channel combination before the actual treatment. This offline computation phase allows the system to evaluate and select optimal transmit configurations that achieve desired energy deposition patterns, reducing the complexity of real-time control during treatment while maintaining precise energy deposition control.
Solution Approach 2:
The patent utilizes parameter changes by independently adjusting the amplitude and phase of each transmit channel to optimize energy deposition. By varying these parameters based on pre-computed SAR matrices and treatment objectives, the system achieves precise control over where RF energy is deposited without requiring complex hardware modifications, leveraging software-based parameter optimization.
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 allows for precise and controlled RF energy deposition, achieving targeted temperature elevations with minimal impact on non-target tissues, enabling personalized medicine and reducing side effects in RF-based hyperthermia treatments.
Implementation Method 1
designing a plurality of RF pulses for achieving a target power deposition in the target region by using the first set of SAR matrices and the second set of SAR matrices in an optimization that determines a set of RF waveforms that produce a target average local SAR in the treatment region
Implementation Method 2
providing a plurality of specific absorption rate (SAR) matrices for estimation of SAR at locations within the subject
Data Source
AI summary
Systems and methods for designing parallel transmission radiofrequency (RF) pulses for use in a RF treatment. The methods include selecting a target region in a subject, and providing a plurality of specific absorption rate (SAR) matrices for estimation of SAR at locations within the subject. The methods also include determining a first set of SAR matrices for locations in the target region using the provided SAR matrices, and determining a second set of SAR matrices for locations not in the target region using the provided SAR matrices. The methods further include designing a plurality of RF pulses for achieving a target power deposition in the target region by using the first set of SAR matrices and the second set of SAR matrices in an optimization that determines a set of RF waveforms that produce a target average local SAR using the first set of SAR matrices while minimizing a local SAR and a global SAR using the second set of SAR matrices.