Cryogenic System and Method of Use

Abstract

A cryogenic medical device for delivery of subcooled liquid cryogen to various configurations of cryoprobes is designed for the treatment of damaged, diseased, cancerous or other unwanted tissues. The device is a closed or semi-closed system in which the liquid cryogen is contained in both the supply and return stages. The device is capable of generating cryogen to a supercritical state and may be utilized in any rapid cooling systems. As designed, the device comprises a number of parts including a vacuum insulated outer dewar, submersible cryogen pump, baffled linear heat exchanger, multiple pressurization cartridges, a return chamber, and a series of valves to control the flow of the liquid cryogen interconnected with cryotreatment devices including cryoprobes and catheters. The cryogenic medical device promotes subcooling to the tips of various external cryogenic instrument configurations.

What is claimed is: 
     
         1 . A cryogenic system comprising:
 at least one cryoprobe having a freeze zone;   a container capable of being filled with a cryogen;   a pressurization apparatus having one or more heaters arranged therein to generate a pressurized cryogen, the pressurization apparatus having at least one port, wherein when the container is filled with the cryogen,
 (i) at least a first portion of the pressurization apparatus is positioned in the cryogen and is at a first temperature, and 
 ii) at least a second portion of the pressurization apparatus is positioned outside the cryogen and is at a second temperature greater than the first temperature; 
   a pump disposed in the container for delivering cryogen to the at least one port, wherein the pump is positioned in the cryogen when the container is filled with cryogen;   at least one supply line in fluid communication with the at least one cryoprobe; and   at least one return line that returns the cryogen from the at least one cryoprobe to the container.