Dielectric Shield for RF Tissue Exposure Power Deposition

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current methods for exposing a region of interest to alternating magnetic fields for cancer therapy face challenges in minimizing non-specific heating in surrounding tissues, particularly in metastatic cancer treatments where deep-tissue tumors are involved, due to the complex nature of living tissue and the inability to discriminate between normal and tumor tissues.

Innovation Solution

An apparatus and method utilizing a dielectric shield, such as water, to attenuate electric field components of radio-frequency electromagnetic radiation while allowing magnetic field components to pass through, thereby reducing power deposition in regions outside the target area and maximizing heat generation in the region of interest using magnetic nanoparticles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If high amplitude radiofrequency electromagnetic fields are applied to heat tumor tissue, then therapeutic heating effect is improved, but non-specific power deposition in surrounding normal tissue increases

Engineering Contradiction:

Improvetumor tissue temperatureVSAvoidnon-specific heating of normal tissue

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

A dielectric shield (intermediary material) is placed between the RF electromagnetic field source and the tissue to selectively attenuate the field. The shield has properties that allow it to block harmful electric field components while permitting magnetic field components to pass through, thereby protecting normal tissue from non-specific heating while enabling therapeutic heating of the tumor region

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The dielectric shield is positioned specifically at the boundary of the region of interest to provide localized protection. This creates a spatially differentiated field distribution where the shielded region (normal tissue) experiences reduced power deposition while the unshielded region (tumor tissue) maintains therapeutic heating levels

Inventive Principle:

Principle #3Local quality

2Volume of moving object

If alternating magnetic fields are used to expose deep-tissue tumors, then treatment of metastatic cancer is improved, but discrimination between normal and tumor tissues becomes more difficult

Engineering Contradiction:

Improvedepth of tissue treatmentVSAvoidspatial selectivity of heating

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The dielectric shield serves as an intermediary that restores spatial selectivity by selectively attenuating electromagnetic fields in specific regions. This allows deep-tissue treatment while re-establishing the ability to discriminate between treated and protected regions through controlled field distribution

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The treatment space is segmented into shielded and unshielded regions, creating distinct zones with different field characteristics. This segmentation enables selective heating of deep tumor tissue while protecting overlying normal tissue, effectively dividing the treatment volume into functionally different zones

Inventive Principle:

Principle #1Segmentation

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

The use of dielectric shielding effectively reduces non-specific heating by two-fold, allowing for higher amplitude alternating magnetic fields to be maintained at the tumor site while minimizing heat deposition in normal tissues, as demonstrated by computer simulations and experiments with gel phantoms and mouse models.

Implementation Method 1

a shield arranged between the source of radio-frequency electromagnetic radiation and the exposure volume. The shield includes a material that has a sufficient thickness and arrangement to reduce power deposition to at least regions outside of the region of interest

Methodology Applied

Scientific EffectDielectric shielding: Dielectric

Implementation Method 2

Alternating magnetic fields (AMF) in the radiofrequency spectrum can be used to localize heat by heating antigen-targeted magnetic nanoparticles in the cancer tissue

Methodology Applied

Scientific EffectMagnetic hysteresis heating: Magnetic Hysteresis

Implementation Method 3

For MRI, the tissue exposure of RF results from and depends upon the nature of activation of the imaging sequences of high field MRI devices

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9333369B2Systems and methods to reduce power deposition in tissue exposed to radio frequency electromagnetic fields

Publication Date: 2016.05.10 JOHNS HOPKINS UNIVERSITY

AI summary

An apparatus for exposing a region of interest of an object, animal or person to an alternating magnetic field has a source of radio-frequency electromagnetic radiation arranged to provide the alternating magnetic field in an exposure volume defined by the apparatus, and a shield arranged between the source of radio-frequency electromagnetic radiation and the exposure volume. The shield includes a material that has a sufficient thickness and arrangement to reduce power deposition to at least regions outside of the region of interest of the object, animal or person during exposure in the exposure volume.