The cryoablation of lung tissue using liquid nitrogen in gel and in the ex vivo pig lung.

PURPOSES: To examine the efficiency of cryoablation using liquid nitrogen in lung tissue, we measured the size and temperature distribution of the frozen area (iceball) in gel and in the ex vivo pig lungs.

METHODS: Cryoprobes with diameters of 2.4 and 3.4 mm (2.4D and 3.4D, respectively) were used. Three temperature sensors were positioned at the surface of the cryoprobe and at distances of 0.5 and 1.5 cm from the cryoprobe. The ex vivo pig lungs were perfused with 37 °C saline and inflated using ventilator to simulate in vivo lung conditions.

RESULTS: In gel, the 2.4D and 3.4D probes made iceballs of 3.9 ± 0.1 and 4.8 ± 0.3 cm in diameter, respectively, and the temperature at 1.5 cm from those probes reached -32 ± 8 and -53 ± 5 °C, respectively. In the pig lung, the 2.4D and 3.4D probes made iceballs of 5.2 ± 0.1 and 5.5 ± 0.4 cm in diameter, respectively, and the temperature at 1.5 cm from these probes reached -49 ± 5 and -58 ± 3 °C, respectively.

CONCLUSION: Liquid nitrogen cryoablation using both 2.4D and 3.4D probes made iceballs that were of sufficient size, and effective temperatures were reached in both gel and the ex vivo pig lung.