METHOD AND APPARATUS FOR CRYOADHESION
A method and system for continuously delivering cryotreatment to a treatment device. In one embodiment, the system may include a first PID circuit in the fluid delivery line and a second PID circuit in the fluid return line, and the first and second PID circuits may operate simultaneously to continuously provide coolant to a cryotreatment device during the inflation phase, ablation phase, and warming (or thawing) phase while providing for temperature adjustment. Alternatively, the system may include a bypass line by which coolant may bypass the subcooler system and be delivered to the cryotreatment device at non-ablation temperatures during the inflation phase. During the ablation phase, coolant may flow through the subcooler system.
1 . A continuous flow cryotreatment system, the cryotreatment system comprising:
a fluid supply;
a fluid injection line in communication with the fluid supply, the fluid injection line including a first PID circuit having a first PID controller, a first pressure transducer, and a first proportional valve;
a cryotreatment device having a treatment element in communication with the fluid injection line;
a fluid return line in communication with the cryotreatment device, the fluid return line including a second PID circuit having a second PID controller, a second pressure transducer, and a second proportional valve; and
a vacuum source in communication with the fluid return line,
the system being programmable to operate in an inflation phase, a treatment phase, and a warming phase, the first PID circuit and second PID circuit simultaneously operating to control the temperature of the treatment element during the inflation phase, the ablation phase, and the warming phase.
2 . The system of claim 1 , wherein the treatment element defines an expansion chamber, the expansion chamber being in communication with the fluid injection line and the fluid return line, the treatment element having an adjustable temperature based at least in part on the flow of fluid within the expansion chamber from the fluid supply reservoir.
3 . The system of claim 2 , wherein the system further comprises a control unit in communication with the first PID circuit and the second PID circuit, first pressure transducer and the second pressure transducer each measuring pressure within the system, the control unit adjusting the first proportional valve and the second proportional valve based at least in part on the pressure measurements of the first proportional valve and the second proportional valve.
4 . The system of claim 3 , wherein the first pressure transducer measures pressure within the expansion chamber of the cryotreatment device.
5 . The system of claim 3 , wherein the temperature of the treatment element is decreased when the first proportional valve is adjusted to increase the flow rate of coolant into the expansion chamber and when the second proportional valve is adjusted to at least partially open the expansion chamber to the vacuum source.
6 . The system of claim 5 , wherein the temperature of the treatment element is increased when the first proportional valve is adjusted to reduce the flow rate of coolant into the expansion chamber and when the second proportional valve is adjusted to at least partially close the expansion chamber to the vacuum source.
7 . The system of claim 6 , wherein the treatment element is an inflatable element, the inflatable element remaining inflated throughout the treatment phase and warming phase.
8 . The system of claim 7 , wherein the treatment element is positioned proximate an area of target tissue during the treatment phase and the warming phase.
9 . The system of claim 8 , wherein the temperature of the treatment element during the warming phase is less than approximately 0° C. but greater than a temperature at which the treatment element ablates the target tissue.
10 . The system of claim 9 , wherein the first PID circuit and the second PID circuit each further include a solenoid valve.
11 . A method for treating an area of target tissue, the method comprising:
positioning a cryotreatment device including a treatment element defining an expansion chamber proximate the area of target tissue, the expansion chamber being in fluid communication with a fluid flow path, the fluid flow path including:
a fluid supply containing coolant;
a fluid injection line in communication with the fluid supply and the expansion chamber, the fluid injection line including a first PID circuit having a first PID controller, a first pressure transducer, and a first proportional valve;
a fluid return line in communication with the cryotreatment device, the fluid return line including a second PID circuit having a second PID controller, a second pressure transducer, and a second proportional valve; and
a vacuum source in communication with the fluid return line,
the system being programmable to operate in an inflation phase, an ablation phase, and a warming phase, the first PID circuit and second PID circuit simultaneously operating to control the flow rate of coolant into and out of the expansion chamber during the inflation phase, the ablation phase, and the warming phase; and
continuously delivering coolant to the expansion chamber during the inflation phase, the ablation phase, and the warming phase, the first PID circuit operating to deliver coolant to the expansion chamber at a first flow rate during the inflation phase, a second flow rate during the ablation phase, and a third flow rate during the warming phase.
12 . A continuous flow cryotreatment system, the cryotreatment system comprising:
a coolant supply;
a fluid injection line in communication with the fluid supply, the fluid injection line including a subcooler;
a bypass line in communication with the fluid injection line, the bypass line including a valve, an inlet upstream of the subcooler, and an outlet downstream of the subcooler;
a cryotreatment device having a treatment element in communication with the fluid injection line;
a fluid return line in communication with the cryotreatment device; and
a vacuum source in communication with the fluid return line,
the system being programmable to operate in an inflation phase, a treatment phase, and a warming phase, the coolant continuously flowing through the bypass line during the inflation phase and through the subcooler during the ablation phase.
13 . The system of claim 12 , wherein the treatment element defines an expansion chamber, the expansion chamber being in communication with the fluid injection line and the fluid return line, the treatment element having an adjustable temperature based at least in part on the flow of coolant within the expansion chamber.
14 . The system of claim 13 , wherein the bypass line valve is substantially open during the inflation phase and substantially closed during the ablation phase.
15 . The system of claim 14 , wherein the bypass line valve is substantially open during the warming phase.
16 . The system of claim 14 , wherein the treatment element is an inflatable element, the inflatable element remaining inflated throughout the treatment phase and the warming phase.
17 . The system of claim 15 , wherein the treatment element is positioned proximate an area of target tissue during the treatment phase and the warming phase.
18 . The system of claim 17 , wherein the temperature of the treatment element during the warming phase is less than approximately 0° C. but greater than a temperature at which the treatment element ablates the target tissue.
19 . A method for treating an area of target tissue, the method comprising:
positioning a cryotreatment device including a treatment element defining an expansion chamber proximate the area of target tissue, the expansion chamber being in fluid communication with a fluid flow path, the fluid flow path including:
a coolant supply;
a fluid injection line in communication with the fluid supply and the expansion chamber, the fluid injection line including a subcooler;
a bypass line in communication with the fluid injection line, the bypass line including a valve, an inlet upstream of the subcooler, and an outlet downstream of the subcooler;
a fluid return line in communication with the cryotreatment device; and
a vacuum source in communication with the fluid return line,
the system being programmable to operate in an inflation phase, an ablation phase, and a warming phase, the coolant flowing through the bypass line during the inflation phase and through the subcooler during the ablation phase; and
continuously delivering coolant to the expansion chamber during the inflation phase, the ablation phase, and the warming phase, the bypass line valve being substantially open during the inflation phase and substantially closed during the ablation phase.
20 . An improvement for a fixed initial volume cryoablation system, the improvement comprising:
a PID circuit including a PID controller, the PID circuit in communication with a fluid return line and operating simultaneously with a first PID circuit in communication with a fluid injection line to adjust fluid flow rate within the system,
the PID circuit allowing the system to operate as a continuous flow system.