The cooling performance of a cryoprobe: Establishing guidelines for the safety margins in cryosurgery

• This is the first paper that validates cooling performance of clinically used cryoprobe.
• This paper provides information that is useful to medical doctors for operating cryosurgery.
• The guideline is given for determining the size of oversized ice ball.
• The data are uniquely analyzed with an insight from thermal engineering point of view.
• This is the first paper that clearly indicates the cooling power of a cryoprobe.

Cryosurgery is a minimally invasive surgical technique that uses cryoprobes or cryoneedles to freeze and destroy tumors or undesirable tissues. It is supported by non-invasive monitoring technologies such as MRI and ultrasonography, which make it possible to distinguish frozen regions in tissues and organs. However, the application of an ice ball to a cancerous tissue cannot guarantee the eradication of the complete tumor. Exposing all cancer cells to the lethal temperature, while minimizing the exposure of the healthy tissue to avoid side effects, is necessary. Therefore, the size of the ice ball is a key issue in cryosurgery. However, no data on the performance of clinically used cryoprobes are available in the open literature. The objective of this study was to experimentally validate the cooling performance of a widely used Joule–Thomson cryoprobe, to investigate the growth of the ice ball and cooling power of the probe, and to suggest guidelines for establishing the safety margin at the ice periphery. A numerical simulation was also carried out, and the results were compared with the experimental findings.