P1.17-02 The Investigation of Intraoperative Marking by Transbronchial Low Power Laser Irradiation in Human Lung

Abstract

Small lung nodules which appear to be ground glass opacity in peripheral lung are difficult to identify during surgery. In order to identify the site of such lesions, various types of preoperative or intraoperative marking methods have been reported. However, there is no definitive way. Therefore, we have reported a new safe and reliable intraoperative marking method using low power laser light. By irradiating low power laser close to the lesion from a bronchus, the site of the lesion can be identified from the lung surface by looking at the laser light. We conducted an animal experiment and were able to observe the laser light irradiated in bronchus from the lung surface. In this study, we performed laser irradiation to the resected human lung to confirm whether the laser light can actually be observed safely from lung surface. The patient was 70-year-old male (40 pack-years ex-smoker). The adenocarcinoma (55×40mm) was located at right S2 area. Immediately after right upper lobectomy, a plastic cylindrical-type laser probe was inserted into peripheral bronchus of the resected lung. The probe was very thin (0.8mm diameter) and flexible. Therefore, it can be inserted into the peripheral lung. It was developed jointly with Keio University. The probe was induced just below the pleura and 70mW low power laser irradiation was performed. We examined whether laser light could be confirmed from lung surface. The effect of laser irradiation to the lung tissue was evaluated pathologically. When the probe was guided to just below the pleura, laser light could be clearly observed from the lung surface. After that, the probe was gradually withdrawn. The laser light could be observed until the depth of 10mm from the pleura. No damage was obtained around the laser irradiated area in pathological findings. The observable depth of laser light was slightly shallow at10mm. The reasons of this were guessed that lung expansion was not sufficiently because harvested lung was used, so the density of lung tissue was increase and pleural thickening and anthracosis were observed in the lung because of his smoking history. It might be possible to confirm the localization of small nodules in peripheral lung using low power laser light during surgery.