[1] Similarly to standard image-guided surgery, FGS has the purpose of guiding the surgical procedure and providing the surgeon of real time visualization of the operating field.
In recent years a number of commercial companies have emerged to offer devices specializing in fluorescence in the NIR wavelengths, with the goal of capitalizing upon the growth in off label use of indocyanine green (ICG).
[8] A stand or arm can be used to maintain the system on top of the operating field, particularly when the weight and complexity of the device is high (e.g. when multiple cameras are used).
The main disadvantage of such devices is that operating theater lights can interfere with the fluorescence emission channel, with a consequent decrease of signal-to-background ratio.
Nevertheless, the excitation power density at the sample is limited by the low light transmission of the fiber optics in endoscopes and laparoscopes, particularly in the near infrared.
[14] The first uses of FGS dates back to the 1940s when fluorescein was first used in humans to enhance the imaging of brain tumors, cysts, edema and blood flow in vivo.
[15] In modern times the use has fallen off, until a multicenter trial in Germany concluded that FGS to help guide glioma resection based upon fluorescence from PpIX provided significant short-term benefit.