Principles and Practice of Intraoperative Fluorescence Imaging

Fluorescence-guided surgery (FGS) is an optical-based, real-time, intraoperative imaging technique, which can effectively expand the visual range of surgeons and assist clinical decision-making. Due to the radioactivity and the difficulty of long-term, continuous, real-time in vivo imaging, traditional imaging methods for preoperative diagnosis and postoperative evaluation are inappropriate for the continuous, real-time, in vivo imaging that is necessary for surgical guidance. Thus, visual and tactile sensing combined with the experience of the physician are still the key factors affecting the surgical outcome. Therefore, there is an urgent need for an intraoperative imaging technique to distinguish lesions from normal tissues, important vessels, and organs. FGS has the advantages of high sensitivity, contrast, and specificity, without exposing the patient to ionizing radiation. It also has the capability to identify the boundaries and reflect the position of superficial lesions during a surgical operation, thus providing the technical means for the early detection and precise resection of small lesions. The validation of FGS technology’s performance through both imaging equipment development and standardization and clinical trials is expected to reduce iatrogenic trauma and improve the postoperative survival rates and quality of life. This chapter focuses on excitation fluorescence imaging and its clinical applications. Following a description of the principles underlying this technology, the three main fluorescent agents currently in clinical use are presented. Some representative clinical FGS systems, either for open or endoscopic surgery, are described, and the still unmet need for standardization of FGS systems and methods is discussed.