John D. Dobak

A Review of Cryobiology and Cryosurgery

Cryosurgery is the destruction of tissue by freezing. Modern cryosurgical techniques were first introduced in the mid 1960’s, but, they only achieved modest application in selected medical specialties. This was in part due to limitations in cryosurgical devices which could not address the fundamental factors that influence cell death in response to freezing. It was also due to an inability to accurately assess or predict the growth of the ice ball within the tissue, and more importantly determine the zone of tissue death. Recent advances in liquid nitrogen cryosurgical devices and ultrasound guided cryosurgical techniques have addressed some of these issues, have significantly raised the interest in cryosurgery, and have expanded its application. Newer advances in cryosurgical devices and magnetic resonance imaging have great promise in making cryosurgery a primary therapeutic modality. This paper will review the biologic issues related to the freezing of tissue and their impact on the development of cryosurgical devices, as well as discuss the newest developments at the forefront of cryosurgical applications.

A novel closed loop cryosurgical device

A novel cryosurgical device has been developed that dramatically improves the cost, convenience, safety, and effectiveness of cryosurgical devices. The device incorporates a mixed gas J-T stage. The fluid mixture is non flammable, non toxic, non corrosive, environmentally safe, and therefore suitable for medical applications. The system is compressor driven utilizing a novel oil free motor. Working temperatures of -115 to -125 °C at pressures of 300 to 350 psi are achieved. Approximately 20 watts of refrigeration are delivered at -120 °C.