Varying Temperature Sensor Length in Cooled RF Probes
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Solution Overview
Problem
Current cooled radiofrequency probe systems lack the ability to vary the length of temperature sensing elements, limiting the flexibility in achieving desired lesion sizes and power delivery rates for effective treatment of tissue, particularly in sensitive anatomical locations.
Innovation Solution
The system includes a plurality of cooled radiofrequency probes with temperature sensing elements of varying lengths, allowing selection based on desired lesion size or power delivery, and features a closed-loop cooling system to decouple temperature control from the power source, enabling precise energy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-length temperature sensing element is used in cooled radiofrequency probes, then the device structure is simple and easy to manufacture, but the flexibility in achieving desired lesion sizes and power delivery rates is limited
Solution Approach 1:
The temperature sensing element is designed with a flexible membrane structure that allows it to dynamically adjust its effective length by expanding or contracting in response to pressure changes. This enables the same probe to adapt to different lesion size requirements without requiring multiple fixed-length probes, thus improving versatility while maintaining relatively simple device structure.
Solution Approach 2:
The sensing element's physical state is changed by applying pressure to alter its length. By controlling the pressure applied to the flexible membrane, the effective length of the temperature sensing element can be varied, allowing customization of lesion size and power delivery rates according to specific treatment requirements.
2Volume of stationary object
If higher power is applied to extend lesion size in cooled radiofrequency treatment, then the lesion volume increases, but the risk of tissue desiccation, charring, or steam formation increases
Solution Approach 1:
The flexible membrane temperature sensing element provides real-time temperature feedback from the tissue interface. This feedback is used to dynamically adjust the radiofrequency power delivery, allowing higher power to be applied safely by continuously monitoring temperature and preventing conditions that lead to desiccation, charring, or steam formation, thus enabling larger lesion volumes without increasing harmful effects.
Solution Approach 2:
The flexible membrane acts as an intermediary between the radiofrequency energy delivery system and the tissue. It provides direct temperature measurement at the tissue interface, enabling precise control of energy delivery to achieve larger lesion volumes while preventing harmful thermal effects through real-time monitoring and adjustment.
3Measurement precision
If the temperature sensing element length is increased, then the temperature control precision is improved, but the maximum power delivery capability is reduced
Solution Approach 1:
The flexible membrane temperature sensing element can dynamically change its length to optimize the balance between temperature control precision and power delivery capability. For treatments requiring high power, the element contracts to reduce its length and associated thermal mass. For treatments requiring precise temperature control, the element expands to increase its length and improve measurement accuracy, thus adapting to different treatment requirements.
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 approach allows for customized lesion sizes and power delivery, enhancing treatment efficacy by preventing over-ablation in sensitive areas and optimizing energy output while maintaining precise temperature control.
Implementation Method 1
The electrically and thermally-conductive energy delivery devices each have one or more internal lumens for circulating a cooling fluid therethrough
Implementation Method 2
an electrically and thermally-conductive protrusion having a temperature sensing element
Implementation Method 3
The RF electrical current is typically delivered from a generator via connected electrodes that are placed in a patient's body... Tissue resistance to the current causes heating of tissue adjacent resulting in the coagulation of cells
Data Source
AI summary
A method for preparing a cooled radiofrequency probe for use to treat tissue of a patient's body includes providing a plurality of cooled radiofrequency probes. Each of the plurality of cooled radiofrequency probes includes an elongate member with a distal region and a proximal region. The distal regions each have an electrically and thermally-conductive energy delivery device for delivering one of electrical and radiofrequency energy to the patient's body. The electrically and thermally-conductive energy delivery devices each have one or more internal lumens for circulating a cooling fluid therethrough and an electrically and thermally-conductive protrusion having a temperature sensing element. The temperature sensing elements of each protrusion extends from a distal end of the energy delivery device. Further, each of the temperature sensing elements has a different length that extends from the distal end of the energy delivery device. The method further includes determining at least one of a desired lesion size or a desired rate of power delivery required to treat the tissue. As such, the method includes selecting one of the probes from the plurality of cooled radiofrequency probes based on the length of the temperature sensing element thereof that achieves the desired lesion size or the desired rate of power delivery.