Comparison of Probe Materials for Tissue Cryoablation: Operational Properties of Metal and Sapphire Cryoprobes

Typical probes that are used for cryosurgical applications are manufactured from metals, since such materials as copper and brass feature high thermal conductivity at low temperatures and enable rapid growth of an ice ball in living tissues. Due to a favorable combination of properties, sapphire could be also widely used for tissue cryoablation. In this paper, a sapphire probe is experimentally compared with metal ones. Using a gel-based biotissue phantom, an ice ball volume and phantom temperatures in control points are analyzed for the considered probe materials aimed at revealing the advantages of using sapphire for cryosurgery. Next, the impact of probe-tissue contact on the sample and probe surface is studied. The experimental results and qualitative comparison of the considered cryoprobes demonstrate the abilities of the sapphire one for faster tissue freezing, reaching lower temperatures and featuring less damage of its contact surface and adjacent tissues, justifying a potential of sapphire as a material for tissue cryosurgery.