Minimally invasive ablation of pulmonary nodules performed with an optical fiber microcavity thermal probe

Pulmonary nodule is one of the symptoms of early lung cancer, precise treatment of which is essential for improving the patient survival rates. In this paper, we propose a novel fiber micro probe for pulmonary nodule ablation based on an Fabry-Perot (F-P) interferometer filled with nano silver solution (NSS). The micro probe has a high heating efficiency due to the excellent photothermal effect of NSS, enabling efficient ablation of lung nodules. The NSS in the optical fiber microcavity is heated, causing its effective refractive index (RI) changed and resulting in the F-P interference dip shifting of the output spectrum of the probe. The temperature field distribution near the probe is also studied. Temperature of the probe can be monitored and controlled precisely by adjusting the output power of the laser to avoid additional damage to normal tissues or bronchial cells by monitoring the output spectrum in real-time. The micro probe is inserted a lung model with biomimetic nodules made from paraffin with similar melting points as actual nodules using minimally invasive means. Temperatures in the micro probe is raised up to the required for ablating nodules in 240 ms and biomimetic nodules is completely melted within 40 s. The fiber optic thermal ablation needle micro probe provides a strong compactness, high biocompatibility, excellent stability and repeatability, making it an ideal novel method for treating pulmonary nodules and great guiding significance in new medical equipment.