Vitamin B2 lung-marking method using black light irradiation

Small lung lesions without pleural changes that are difficult to palpate are subjected to lung-marking prior to lung tumor resection, to better visualize the location of the tumor. To date, various lung-marking methods are being studied. In clinical practice, the percutaneous computed tomography (CT)-guided hook wire localization method is often used, owing to the simplicity of the technique (1,2). In Japan, the Guiding-Marker System (GMS, Hakko Co., Ltd., Nagano, Japan) is used for around 2,000 cases annually. Although rare, the hook wire localization method is associated with air embolism, which can be lethal (3). Given that vitamin B2 is harmless to the body and is fluorescent, we have reported various methods to apply it to thoracic surgery (4-6). In this study, we aimed to establish a facile and safe lung-marking method and proposed a novel lung-marking method of injecting a vitamin B2 aqueous solution under the visceral pleura. We assessed this method with the idea of applying vitamin B2 marking to human clinical practices in the future, and to that effect, we aimed to evaluate whether this method can replace the existing hook wire localization method, through animal experiments using adult pigs