摘要： Surgery, by its very nature, relies on the ability of the surgeon to visualize and distinguish healthy and non-healthy tissue or structures. Without advanced technology, surgeons can visualize only that which can be seen with the naked eye or using white light imaging. Critical information on tissues, anatomical structures and physiological processes remain hidden and difficult to discern. Fluorescence imaging augments the basic surgical information. This form of imaging entails injecting a contrast or fluorescence agent (fluorophore) that is then illuminated by the appropriate wavelength of light required to excite the fluorophore. The excited fluorophore emits light of a slightly longer wavelength that is selectively imaged to produce a fluorescence image. The first fluorescent agent used in surgery was an intravenous injection of fluorescein, where it was used to enhance intracranial neoplasms. One particular imaging agent, indocyanine green, has been a significant driver of adoption of fluorescence imaging. Indocyanine green was first developed in 1955 by Kodak Research Laboratories and was approved by the Food and Drug Administration (FDA) in 1959 for retinal angiography. Since that time, this fluorophore has been used for a variety of surgical applications due to its unique properties: relative non-toxicity, depth of visualization through tissue, and remaining confined to intravascular and lymphatic spaces due to binding predominately to lipoproteins. The large depth of visualization results from the fluorescence properties of bound indocyanine green which is optimally excited with 805 nm light and emits over an approximate wavelength range from 810 nm to 875 nm. These near infrared wavelengths, invisible to the naked eye, pass through tissue particularly well due to the low adsorption of light by the various structures of tissue, such as hemoglobin and water. As a result, the tissue is relatively transparent to this light and images of structures as much as 5 mm below the tissue surface can be formed. By comparison, fluorescence imaging with fluorescein images only 2–3 mm below the tissue surface; thus subsurface structures cannot be imaged using visible fluorophores.