Annular Phased Array Hyperthermia System Deep Focal Heating
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Solution Overview
Problem
Current hyperthermia systems for cancer treatment face challenges in achieving a small, deep focal heating zone within the human torso without causing damage to surrounding normal tissues, particularly when treating tumors located deep within large tissue masses like the pelvis, abdomen, or thorax, as they often result in excessive heating of normal tissues and the creation of hot spots.
Innovation Solution
An annular phased array system operating at higher frequencies (200-300 MHz) with specifically designed antenna configurations and bolus media to achieve a smaller, selectively heated focal zone, ensuring that the heating zone is centered and minimizes heating of normal tissues, using a dielectric constant lower than water to prevent superficial hot spots and maintain deep penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional hyperthermia systems use lower frequencies to achieve deep penetration, then penetration depth is improved, but the focal zone size becomes too large causing excessive heating of normal tissues
Solution Approach 1:
The patent changes the operating frequency parameter from conventional lower frequencies (e.g., 13.56 MHz) to higher frequencies (200-300 MHz). This parameter change enables both adequate penetration depth and reduced focal zone size, resolving the contradiction between penetration depth and focal zone size. The higher frequency electromagnetic radiation creates a more confined focal region while maintaining sufficient penetration into deep-seated tumors.
Solution Approach 2:
The patent employs a phased array configuration with multiple independently controllable antenna elements arranged in specific geometric patterns. By controlling the phase and amplitude of each element, the system achieves three-dimensional focal zone confinement and steering capability. This dimensional control allows the focal zone to be positioned precisely at deep tumor locations while maintaining a small size, resolving the contradiction between penetration depth and focal zone size.
2Area of stationary object
If higher frequencies are used to reduce focal zone size, then focal zone size is improved, but normal tissue heating and hot spot formation increase
Solution Approach 1:
The patent divides the transmitting system into multiple independently controllable antenna elements within a phased array configuration. Each element can be individually adjusted in terms of power amplitude and phase. This segmentation allows precise control over the electromagnetic field distribution, enabling the system to concentrate energy in the desired focal zone while minimizing heating in surrounding normal tissues, thus resolving the contradiction between focal zone size and normal tissue heating.
Solution Approach 2:
The patent incorporates temperature sensing and monitoring mechanisms that provide feedback to the control system. This feedback enables real-time adjustment of the phased array parameters to maintain the focal zone temperature within therapeutic ranges while preventing excessive heating of normal tissues. The feedback control resolves the contradiction by dynamically balancing focal zone size reduction against normal tissue heating prevention.
3Measurement precision
If conventional phased arrays are used with multiple independently controlled channels, then focal zone positioning accuracy is improved, but system complexity increases
Solution Approach 1:
The patent designs the phased array system with antenna elements that can be grouped into channels, where each channel controls multiple elements. This multi-functional approach allows the system to achieve precise focal zone positioning through coordinated control of multiple elements per channel, while reducing overall system complexity compared to fully independent element control. The universal channel structure performs multiple functions including beam forming, focal steering, and temperature control.
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 system effectively heats targeted tissue to higher temperatures with reduced normal tissue damage, increasing the therapeutic benefit of hyperthermia treatment while minimizing toxicity, by achieving a focal zone size of approximately 8 cm in diameter or less with adequate penetration depth.
Implementation Method 1
An array of electromagnetic radiator applicators is provided surrounding the body of an adult size tissue mass and operated at a frequency range of 200 to 300 MHz, or greater
Implementation Method 2
The space between the antennas and the body is filled with the customary bolus having a bolus media therein. The bolus media has a dielectric constant which is much greater than 1. However, for use with higher frequency radiation signals, the bolus media must also have a dielectric constant which is lower than that of water which is 78 to minimize superficial hot spots and also preserve a deep selective central focus
Implementation Method 3
Current systems for applying electromagnetic radiation (EMR) to targets, such as living bodies and biological tissue, and controlling the position of a region of heating within the target through phased array power steering
Data Source
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AI summary
A radio frequency annular phased array hyperthermia system providing a relatively small heated focal zone in a relatively large tissue mass includes a plurality of radio frequency energy applicators in at least one ring adapted to surround the relatively large tissue mass. A bolus having a dielectric constant is positioned between the energy applicators and the tissue mass. The energy applicators operate at a frequency high enough to create the relatively small heated focal zone. The spacing between adjacent applicators in the at least one ring is less than a critical distance and spacing between adjacent rings when the at least one ring is a plurality of side by side rings is less than a critical distance with such critical distances being interdependent on the frequency of the energy radiated, the dielectric constant of the bolus, the size of the bolus, and the size of the relatively large tissue mass.