Microwave Ablation Feedline Temperature Sensing for Tissue Protection
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Solution Overview
Problem
Existing microwave ablation devices lack precise temperature monitoring, leading to potential damage to healthy cells due to the narrow temperature differential between malignant and healthy tissue.
Innovation Solution
Incorporation of temperature sensors along the feedline of the microwave ablation device, including a first temperature sensor proximal to the balun and optionally additional sensors at various axial locations, to provide accurate temperature readings and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic energy is applied to heat tissue for tumor cell destruction, then malignant tissue is effectively treated, but healthy cells may be damaged due to the narrow temperature differential
Solution Approach 1:
The patent implements real-time temperature monitoring using thermocouples positioned at multiple locations along the feedline and antenna. The temperature sensing circuit continuously measures temperature and provides feedback to the control circuit, which adjusts the microwave power output accordingly. This closed-loop feedback system ensures that tissue temperature remains within the therapeutic window (42-48°C for tumor destruction) without exceeding temperatures that would damage healthy cells (>50°C), thereby resolving the contradiction between effective tumor treatment and healthy cell protection.
Solution Approach 2:
The patent divides the temperature monitoring function into multiple independent temperature sensors (thermocouples) positioned at different axial locations along the feedline and antenna structure. This segmentation allows for spatially-resolved temperature measurement, enabling the system to detect temperature gradients and hot spots throughout the treatment zone. By monitoring temperature at multiple discrete points rather than a single location, the system can more precisely control heating distribution and prevent localized overheating that would damage healthy tissue while ensuring adequate heating of tumor cells.
2Object-affected harmful factors
If temperature monitoring is implemented to achieve precise temperature control, then damage to healthy cells is minimized, but device complexity increases
Solution Approach 1:
The patent employs thermocouples that utilize the Seebeck effect to generate voltage signals directly from temperature differences, eliminating the need for external power supply or complex signal conditioning circuits at the sensor locations. The thermocouples are electrically connected to the existing microwave transmission system, using the same conductors to both transmit microwave energy and sense temperature. This self-powered approach reduces device complexity by avoiding additional power supply circuits, signal amplifiers, and processing electronics that would otherwise be required for active temperature sensors.
Solution Approach 2:
The patent integrates temperature sensing functionality into the existing microwave transmission structure by using the same conductive elements (feedline, antenna) to serve dual purposes: transmitting microwave energy for heating and conducting temperature signals from thermocouples to the sensing circuit. The outer conductor of the coaxial feedline and the antenna elements themselves function as both electromagnetic transmission paths and electrical conduits for temperature measurement signals. This multi-functionality reduces device complexity by eliminating separate temperature sensor housings, additional wiring, and dedicated signal transmission paths that would be required if temperature sensing were implemented as a completely independent subsystem.
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
Enhances precise temperature control, minimizing damage to healthy cells while effectively treating malignant tissue.
Implementation Method 1
The first temperature sensor is disposed at a first axial location of the feedline and is configured to sense a temperature at the first axial location
Implementation Method 2
Treatment may involve inserting ablation probes into tissue where cancerous tumors have been identified. Once the probes are positioned, electromagnetic energy is passed through the probes into surrounding tissue
Implementation Method 3
microwave ablation device includes a cable assembly, a feedline, and a transmission line... electromagnetic energy is passed through the probes into surrounding tissue
Implementation Method 4
The transmission line extends from the first temperature sensor and is disposed parallel and in contact with an outer conductor of the feedline
Data Source
AI summary
A microwave ablation device includes a cable assembly, a feedline, and a transmission line. The cable assembly is configured to connect to an energy source. The feedline is in electrical communication with the cable assembly and includes a first temperature sensor. The first temperature sensor is disposed at a first axial location along a length of the feedline and is configured to sense a temperature at the first axial location. The first temperature sensor extends along the length of the feedline. The transmission line extends from the first temperature sensor and is disposed parallel and in contact with an outer conductor of the feedline.