Cryoablative therapy utilizes a cryoablation probe to damage living tissues by controlling temperature, cooling and thawing rates, the number of cool-thaw cycles. The probe achieves the required operating temperature through the Joule-Thomson effect, using dinitrogen monoxide. Studies on cooling rates reveal two mechanisms responsible for cell death: intracellular ice formation at high cooling rates and cell dehydration at low cooling rates. Moderate cooling rates offer higher probability of cell survival. Ice formation triggers the process of cell death. Improving cryoablation treatments requires assessing physical factors affecting heat exchange at the inner and outer interfaces of the probes. The inner interface involves convection heat exchange through fluid vaporization, while the outer interface engages thermal interaction and ice formation near the probe's surface in contact with the tissue.
Recognizing these occurrences, ice growth, and thermal properties of the tissue are crucial for effective cryoablation. Laser Flash and Hot Disk are used to measure thermal diffusivity and thermal conductivity, respectively. The Laser Flash method heats one side of the material and measures the resulting temperature rise on the opposite side, while the Hot Disk device uses a sensor to evaluate thermal conductivity. These techniques aid in understanding heat transfer and optimizing cryoablation treatments.
Referenti:
Prof. Valter Giaretto
Prof. Elena Campagnoli
Link: https://www.denerg.polito.it/la_ricerca/gruppi_di_ricerca/gruppo_di_ricerca_theam