Ex-vivo human lung tumor model: use for temperature measurements during thermal ablation of NSCLC

In the present study we used an ex-vivo human lung cancer model to compare temperature diffusion during thermal ablation using one laser fiber to that of a two-fiber approach. Furthermore, we examined whether there was a difference between temperature diffusion in normal lung tissue and tumor tissue during laser ablation.

48 resected lung specimens containing non-small cell lung cancer were connected to a perfusion/ventilation apparatus and treated with 1 (22 specimens, group 1) or, in a second experiment, with 1 (13 specimens, group 2) or 2 (13 specimens, group 3) laser fibers. During tumor ablation, temperatures were measured interstitially every 5 sec. Laser ablation was followed by the taking of samples of 13 specimens for histological examination. For comparison we performed laser ablation in 7 specimens with normal lung tissue.

Laser treatment and temperature control were technically feasible in all samples. Thirty min after starting laser ablation with 1 fiber, a temperature of 61 ± 17 °C was achieved in group 1 at a distance of 10 mm from the laser fiber and a temperature of 74 ± 11 °C was achieved in group 2 (p = 0.1). In the middle between two active laser fibers placed 20 mm apart, a temperature of 93 ± 7 °C was achieved. The temperature reached in normal lung tissue after 20 min of laser ablation was 77 ± 15 °C at a distance of 10 mm from the laser fiber.

The ex-vivo model allowed performance of laser-induced thermal ablation in the perfused and ventilated lung. The use of two laser fibers increases the achieved temperatures significantly (p < 0.05). Temperatures reached in normal lung tissue were as high as in tumor tissue (p = 0.24).