EXPERIMENTAL MODEL FOR ICE BALL COMPARISON, CRYO DEVICES TESTING, AND FOR THE ANALYSIS OF ICE BALL ANATOMY.November 1996
F. Lugnani (Contact address: firstname.lastname@example.org)
D. Chinn (Contact address: email@example.com)
Sanatorio Triestino, Trieste; *Alhambra Hospital, Aracadia, California-USA.
Ever since the very first studies on cryosurgical devices, one of the most difficult issues has been to develop a way of testing machines and cryoprobes in a comparable, reproducible, complete manner. It is obvious that the best experimetal model seems to be the live animal, but several economical and practical reasons make it unsuitable for regular testing. Potatoes, sponges, dead animal tissues, surgical specimens, water basins have been used in the past to test the efficiency of the equipements, but even if the models are body-temperature thermostated, and therefore seem to adequatley simulate cryosurgical effects in humans, there are still reasons against their widespread use: potatoes are difficult to prepare and the thermocouples are difficult to insert strait at a given quota and distance from the probe; sponges don't allow an easy calculation of the ice ball diameters; biological tissues are difficult to obtain in suficient quantity and adequate shape; only water permits to see the ice ball growth, is easy to handle, inexpensive, but it is not an adequate medium to keep probes and thermosensors in a steady position. Furthermore, no one has ever desined a rig with a standardized placement of the probes and of the thermocouples, easy to use, effective in data collection, inexpensive to run and usable for different brands of probes. The Authors are presenting a device aiming to ensure the fulfillment of these conditions: built of inert material, with the possibility of testing up to 4 probes simultaneously and with 15 thermocouples placed in selected points at different quotas and distances from one another. The rig has been designed for use in water. It is the Authors' opinion that once probes are tested adequately in water the results may be easily translated easely in an in vivo model using a conversion factor.