Flow rate monitor for fluid cooled microwave ablation probe
A microwave ablation system includes an antenna assembly configured to deliver microwave energy from a power source to tissue and a coolant source operably coupled to the power source and configured to selectively provide fluid to the antenna assembly via a fluid path. The system also includes a controller operably coupled to the power source and a sensor operably coupled to the fluid path and the controller. The sensor is configured to detect fluid flow through the fluid path and the controller is configured to control the energy source based on the detected fluid flow.
1. An electrosurgical ablation system, comprising:
a power source;
an antenna assembly configured to deliver electrosurgical energy from the power source to tissue;
a coolant source operably coupled to the antenna assembly via a fluid path, the coolant source configured to supply a fluid to the antenna assembly through the fluid path;
a sensor operatively coupled to the fluid path, the sensor configured to sense a flow of the fluid through the fluid path and generate a signal indicative of the flow of the fluid;
an amplifier disposed in a resonant feedback loop with the sensor and configured to generate output to a band pass filter centered on a resonant frequency consistent with fluid flow through the fluid path; and
a controller operably coupled to the sensor and the power source, the controller configured to modify output of energy from the power source based on the signal.
2. The electrosurgical ablation system according to claim 1 , wherein the sensor is a capacitive device disposed about the fluid path, the capacitive device configured to sense a capacitance of the fluid.
3. The electrosurgical ablation system according to claim 2 , wherein the capacitive device includes a pair of parallel capacitive plates and a dielectric disposed therebetween.
4. The electrosurgical ablation system according to claim 2 , wherein the controller is configured to compare the capacitance to a predetermined range.
5. The electrosurgical ablation system according to claim 4 , wherein the controller is configured to modify output of energy from the power source based on the comparison of the capacitance to the predetermined range.
6. The electrosurgical ablation system according to claim 1 , wherein the sensor is an electro-mechanical switch operably coupled to the fluid path, the electromechanical switch configured to deflect based on the flow of the fluid.
7. The electrosurgical ablation system according to claim 6 , wherein the electro-mechanical switch is disposed within the fluid path.
8. The electrosurgical ablation system according to claim 1 , wherein the controller is configured to detect an interruption in the flow of the fluid.
9. The electrosurgical ablation system according to claim 1 , wherein the controller is configured to detect at least one peak in the signal.
10. The electrosurgical ablation system according to claim 1 , wherein the fluid path includes a conduit having an inflow lumen and an outflow lumen.