Radio-frequency Ablation System with Interleaved Electrode Switching
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Solution Overview
Problem
Radio-frequency ablation (RFA) for tumor treatment often fails to kill all tumor cells, leading to high recurrence rates due to limitations in energy delivery and uniformity of lesion size, especially when treating multiple or separated tumors with existing bipolar and monopolar probe configurations.
Innovation Solution
A system utilizing multiple monopolar probes operated in an interleaved fashion with an electronic switch to sequentially connect and disconnect them from a radio-frequency power source, allowing for simultaneous treatment with reduced electrical shielding and independent control of each probe's power and temperature, thereby enhancing lesion size and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple monopolar probes are operated simultaneously, then treatment speed increases, but electrical shielding between probes reduces energy delivery effectiveness
Solution Approach 1:
The system operates multiple monopolar probes in an interleaved periodic fashion, sequentially activating each probe rather than simultaneously. This time-division multiplexing approach allows multiple probes to treat the tumor in rapid succession, maintaining high treatment speed while eliminating electrical shielding effects that would occur with simultaneous operation.
Solution Approach 2:
The treatment process is segmented into discrete time intervals, with each probe assigned to a specific time slot. This segmentation of the continuous treatment process into periodic segments allows each probe to operate independently without interference from others, resolving the electrical shielding problem while preserving the benefits of multiple-probe treatment.
2Power
If bipolar operating mode is used, then energy focus and lesion volume increase, but individual control of each probe is lost
Solution Approach 1:
The system uses periodic activation of individual monopolar probes in an interleaved sequence, where each probe receives full power during its active time slot. This creates focused energy delivery similar to bipolar mode during each interval, while maintaining the ability to independently control each probe's parameters when activated.
Solution Approach 2:
The system dynamically switches between different probe configurations and operating modes based on real-time treatment requirements. The electronic switch system allows dynamic reconfiguration of probe connections, enabling individual probe control while achieving bipolar-like energy focus when needed.
3Power
If more energy is delivered to increase lesion size, then tumor ablation effectiveness improves, but tissue charring and vaporization occur
Solution Approach 1:
By delivering energy in periodic intervals to multiple probes rather than continuous high power to a single probe, the system distributes the thermal load across different tissue regions. This prevents localized overheating and charring while achieving the desired lesion size through cumulative energy delivery across multiple treatment cycles.
Solution Approach 2:
The total energy delivery is segmented across multiple probes and time intervals, preventing concentration of excessive energy in one location. Each probe delivers controlled energy pulses that avoid the charring threshold, while the cumulative effect of multiple segmented energy deliveries achieves the required lesion volume.
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 increases the speed and effectiveness of tumor treatment by creating larger, more uniform lesions while allowing for individual control of each probe, reducing recurrence rates and improving treatment precision.
Implementation Method 1
an electrode is inserted into the tumor and current passing from the electrode into the patient (to an electrical return typically being a large area plate on the patient's skin) destroys the tumor cells through resistive heating
Implementation Method 2
A second method actively cools the tip of the electrode with circulated coolant fluids within the electrode itself
Data Source
AI summary
Efficient ablation with multiple electrodes is obtained by rapidly switching electric power to the electrodes. In this way, shielding effects caused by the field around each electrode which would otherwise create cool spots, are avoided. Complex inter-electrode current flows are also avoided.