Cryogenic system

Abstract

A cryosurgical system and method for supplying cryogen to a probe. The system including a container filled with cryogen and having bellows of a pump submerged within said cryogen. Conduits fluidly interconnect the bellows and a probe that is outside the container to permit the cryogen to be forced from the bellows to the probe upon activation of pump. A pressure relief valve is fluidly coupled to the conduits and positioned between the bellows and the probe. After initially forcing cryogen to the probe at a pressure that establishes a colligative-based sub-cooling of the liquid cryogen, the pressure relief valve is activated to lower the pressure of the cryogen to a running pressure.

1 . A cryosurgical system, comprising:
 a container having cryogen within said container;   a pump having a piston, said piston being submerged within said cryogen within said container;   a probe outside the container for use in cryosurgical procedures; and,   a system of conduits fluidly interconnecting said piston and said probe permitting said cryogen to be forced from said piston to said probe upon activation of said piston.   
   
   
       2 . A system according to  claim 1 , wherein said cryogen is liquid nitrogen. 
   
   
       3 . A system according to  claim 1 , wherein said piston is a bellows. 
   
   
       4 . A pump assembly for a cryosurgical system, comprising:
 a driving mechanism coupled to an elongated drive shaft;   a bellows coupled to said drive shaft and adapted to be submersed in cryogen, said bellows formed from metal;   a one-way inlet valve fluidly coupled to said bellows; and   a one-way outlet valve fluidly coupled to said bellows.   
   
   
       5 . A pump assembly according to  claim 4 , further comprising:
 a supply manifold fluidly coupled with said outlet valve, said supply and manifold having a plurality of ports.   
   
   
       6 . A method of delivering cryogen to a surgical device, comprising:
 providing a container having cryogen within the container;   providing a pump having a piston within a cylinder, said piston being submerged within the cryogen within said container;   providing a surgical instrument outside the container for use in cryosurgical procedures;   providing a system of conduits fluidly interconnecting the piston and the surgical device permitting the cryogen to be forced from the piston to the probe upon activation of the piston;   activating the piston to pull cryogen within the cylinder; and,   activating the piston to pull the cryogen from the cylinder to the surgical device to an initial predetermined pressure.   
   
   
       7 . A method according to  claim 6  wherein
 the activating the piston to push the cryogen from the cylinder to the surgical device to an initial predetermined pressure includes pushing the cryogen to the surgical instrument at a pressure of between approximately 250 pounds per square inch and approximately 400 pounds per square inch.   
   
   
       8 . A method according to  claim 6  wherein
 after pushing the cryogen to the surgical device at the initial predetermined pressure, activating the pressure release device to decrease the pressure of the cryogen to a lower pressure that is below the predetermined pressure.   
   
   
       9 . A system according to  claim 1 , further including
 a pressure relief device fluidly coupled to said systems of conduits and positioned between said pump and said probe.   
   
   
       10 . A method according to  claim 6 , further including the step of:
 providing a pressure relief device fluidly coupled to the systems of conduits and positioned between the bellows and the probe.