Microwave Radiometry Probe for Esophageal Temperature Monitoring
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Solution Overview
Problem
Conventional cardiac ablation procedures face challenges in accurately measuring and preventing thermal injury to the esophagus due to its proximity to the left atrium, as existing temperature sensors only monitor surface temperatures and cannot effectively detect overheating at depth, leading to potential severe complications like ulcers and perforation.
Innovation Solution
A temperature sensing microwave antenna probe is inserted into the esophagus to measure esophageal wall temperature at depth using microwave radiometry, providing real-time temperature data independent of the probe's angle and allowing for effective cooling and power control to prevent overheating, while also monitoring the outer surface temperature of the heart.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional point source temperature sensors (thermocouples, thermistors) are used to monitor tissue temperature during ablation, then surface temperature can be measured, but temperature at depth in the esophageal wall cannot be accurately detected
Solution Approach 1:
The patent replaces conventional mechanical contact-based temperature sensors (thermocouples, thermistors) with a microwave antenna probe that uses electromagnetic radiation to measure temperature. The microwave probe detects temperature at depth in the esophageal wall by measuring microwave emissions from the tissue, eliminating the need for direct mechanical contact and enabling deep temperature monitoring without being limited to surface measurements only.
2Object-affected harmful factors
If cooled fluid is circulated through the esophageal catheter to cool the esophagus wall, then thermal injury risk is reduced, but accurate temperature measurement becomes impossible because conventional sensors only measure coolant temperature, not tissue temperature
Solution Approach 1:
The microwave antenna probe uses electromagnetic radiation to measure temperature, replacing the need for conventional contact-based sensors that would be affected by the cooling fluid. The microwave probe can measure the actual tissue temperature at depth even when cooled fluid is circulating, because it detects thermal emissions directly from the tissue rather than measuring the temperature of the cooling medium.
Solution Approach 2:
The microwave antenna acts as an intermediary that can measure temperature through the cooling fluid without being affected by it. The microwave probe measures temperature at depth in the esophageal wall by detecting electromagnetic emissions from the tissue, effectively mediating between the cooling system and the temperature measurement function, allowing both cooling and accurate temperature monitoring to occur simultaneously.
3Productivity
If ablation power is increased to create deeper lesions in the left atrium, then treatment effectiveness is improved, but the risk of inadvertent overheating and injury to the esophagus increases
Solution Approach 1:
The microwave temperature probe provides real-time feedback on the temperature at depth in the esophageal wall during the ablation procedure. This feedback allows the operator to monitor esophageal temperature continuously and adjust ablation power accordingly, enabling deeper and more effective ablation lesions in the left atrium while maintaining safety by preventing inadvertent overheating of the esophagus through continuous temperature monitoring and power adjustment.
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 method enables early detection of potential esophageal damage, facilitating safe cardiac ablation by accurately measuring temperature at depth and surface, reducing the risk of thermal injury and improving patient outcomes by providing timely intervention.
Implementation Method 1
A temperature sensing microwave antenna probe is inserted into the esophagus to measure esophageal wall temperature at depth using microwave radiometry
Implementation Method 2
an electrode catheter is used to resistively heat heart tissue, usually at the left side of the heart, sufficiently to intentionally damage the target tissue
Implementation Method 3
the tips of today's ablation catheter may be cooled by a circulating a fluid through the catheters
Data Source
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AI summary
A method of minimizing thermal trauma during tissue ablation including the steps of placing an ablation catheter at an ablation site on a first organ in a patient's body, providing energy to the ablation catheter to heat first organ tissue at the ablation site, providing microwave radiometry apparatus including a probe containing a microwave antenna and a radiometer responsive to the antenna output for producing a temperature signal corresponding to the thermal radiation picked up by the antenna, positioning the probe in a body passage of a second organ in the patient's body having a wall portion adjacent to the ablation site so that the microwave antenna is located at a measurement site opposite the ablation site, using the radiometry apparatus, measuring the temperature at depth in the second organ tissue at the measurement site to provide a corresponding temperature signal, and controlling the ablation catheter in response to the temperature signal to maintain the temperature of the second organ tissue below a predetermined value that does not result in thermal trauma to the second organ tissue. Apparatus for carrying out the method is also disclosed.