Microwave Coagulation Applicator Cooling Sleeve
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Solution Overview
Problem
Existing microwave applicators for tissue coagulation and ablation face challenges in achieving consistent and predictable heating patterns, effective cooling of the applicator shafts, and minimizing damage to surrounding normal tissues.
Innovation Solution
The microwave applicator features an elongate body with a coaxial microwave energy transmission line, an outer conductive sleeve for cooling, and a guide sleeve to direct circulating cooling fluid, ensuring the applicator shaft remains below tissue-damaging temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If microwave energy is applied to heat tissue for coagulation or ablation, then the temperature in the targeted tissue is elevated to kill cells, but the temperature in surrounding normal tissue may also rise to damaging levels
Solution Approach 1:
The patent employs multiple antennas with independent power control to create localized heating zones. Each antenna can be individually adjusted to deliver precise power levels to specific regions, ensuring that only the targeted tumor tissue receives high thermal doses while surrounding normal tissue remains protected. This spatially differentiated power distribution enables selective heating of pathological tissue without collateral thermal damage.
2Power
If high power microwave energy is used to ensure adequate heating throughout the entire tumor, then coagulation or ablation is achieved, but the risk of damage to surrounding normal tissues increases
Solution Approach 1:
The patent divides the treatment field into multiple independent zones, each covered by a separate antenna. This segmentation allows the total microwave power to be distributed across multiple independent channels, each controllable at different power levels. High power can be applied to tumor regions requiring ablation, while adjacent normal tissue regions receive reduced or zero power, thereby eliminating the need to choose between adequate tumor heating and normal tissue protection.
3Device complexity
If the applicator shaft is not cooled, then the structure remains simple, but the applicator shaft may heat to undesirably high temperatures causing thermal damage to normal tissue through which it passes
Solution Approach 1:
The patent introduces a cooling fluid as an intermediary substance that circulates through channels in the applicator shaft. This cooling fluid acts as a thermal mediator, absorbing heat from the applicator shaft and transmission line without requiring direct contact with the treatment site. The cooling system is integrated into the applicator structure itself, allowing passive heat removal while maintaining the simplicity of the overall device design.
4Temperature
If cooling fluid is circulated through the applicator, then the applicator shaft temperature is controlled, but the device complexity increases
Solution Approach 1:
The patent combines multiple functions into the applicator shaft structure: the shaft itself serves as both the mechanical support for the antenna and as a heat exchanger for the cooling fluid. The cooling channels are integrated within the shaft walls, eliminating the need for separate cooling components. This merging of structural and thermal management functions achieves effective temperature control while minimizing the increase in device complexity.
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 design provides more consistent and predictable heating patterns, effectively cools the applicator shafts, and minimizes damage to surrounding normal tissues, enhancing the safety and efficacy of microwave coagulation and ablation treatments.
Implementation Method 1
An antenna for radiating microwave energy into tissue to be treated is disposed toward the insertion end of the elongate applicator body
Implementation Method 2
microwave energy radiated from the antenna penetrates and heats the tissue
Implementation Method 3
A guide sleeve is positioned concentrically within this cooling fluid space and spaced inwardly from the outer conductive sleeve and around the outside of and spaced outwardly from the microwave energy transmission line. The guide sleeve guides flow of a circulating cooling fluid along the outside surface of the microwave energy transmission line and the inside surface of the outer conductive sleeve to cool the microwave energy transmission line and the conductive outer sleeve
Implementation Method 4
A coaxial microwave energy transmission line is disposed within the applicator body to conduct microwave energy from the attachment end of the applicator to the antenna
Implementation Method 5
A temperature sensor is positioned to measure the approximate temperature of the circulating cooling fluid thereby indicating that the microwave energy transmission line and the outer conductive sleeve are being actively cooled during the microwave coagulation or ablation treatment
Data Source
AI summary
A microwave applicator for insertion into living body tissue for use in microwave coagulation and ablation treatments includes a microwave transmission line extending between an attachment end of the applicator and an antenna toward an insertion end of the applicator with an outer conductive sleeve forming an enclosed cooling fluid space around the transmission line. Circulation of cooling fluid is guided in the cooling fluid space by a guide sleeve. A fluid circulation system provides a plurality of fluid supply connectors and fluid return connectors which can be connected and used with any number of applicators between one and the number of the fluid supply connectors provided by the system. A portion of the applicator inserted into the tissue can stick to the tissue to stabilize the applicator during treatment. A warning marking on the applicator can be used during track ablation to prevent ablation of the patient skin tissue.