The International
Society For
Fluorescence Guided Surgery (ISFGS)

What is Fluorescence Guided Surgery?

Fluorescence Guided Surgery (FGS) is a medical imaging technique that uses fluorescent dye to identify anatomic structures during surgical procedures. FGS typically involves three components:

1. Fluorescent Dye: The most commonly used fluorescent agent is Indocyanine Green (IGC). ICG has been approved by the FDA in 1959 and has demonstrated to be safe and can be used in different surgical applications. 

2. An Excitation Source:The ICG is illuminated with a specific light source that causes the dye to glow. This enhances the structure in which the surgeon needs to see. 

What are the advantages of Fluorescence Guided Surgery?

Despite many advances in preoperative medical imaging such as CT and MRI scans, surgeons still almost exclusively operate under white (visible) light during their procedures and must rely on their ability to see and feel target tissues. Unfortunately, most human tissue looks very similar under white light, and it can be very difficult to distinguish one tissue from another or to completely remove a target tissue such as a tumor. In addition, a surgeon can only see the topmost layer of tissue under white light while tissues and structures underneath will remain hidden.

FGS essentially gives the surgeon the ability to ‘see’ in a different wavelength of light that would otherwise be invisible to them. By combining this visual ability with the special dyes that glow in those wavelengths surgeons can much more precisely target or avoid certain organs or tissues. In addition, the near-infrared light used in FGS can more easily penetrate human tissues, allowing surgeons to see ‘through’ layers of tissue and organs.

In addition to allowing a surgeon to see what otherwise would be invisible, FGS has the added advantage of being a real-time imaging process. Whereas traditional imaging like X-Rays, CT Scans, and MRI scans can provide excellent images, they are all limited to providing static images.

Think of FGS as being the equivalent of giving a surgeon GPS whereas before they were working with only a map!

How is FGS Currently Being Used?

This table from this article outlines the current clinical and preclinical fluorescence-guided surgery techniques:

Application Types  
     
 Angiography and Tumor Identification Coronary artery bypass grafting   
  Cerebral aneurysm  
  Reconstructive surgery  
  Colorectal resections  
  Esophagectomy  
  Gastrectomy  
  Brain aneurysm  
  Endonasal surgery  
  Angiography  
  Brain tumor  
  Thyroid and parathyroid surgery  
     
     
     
Structures Identification  Ectrahepatic bile ducts  
  Ureters  
     
     
     
 Lymph Vessels Evaluation of lymphedema   
     
       
   
SLN Identification Melanoma
  Breast Cancer   
  Endometrial Cancer   
  Gastric Cancer   
     

 

What is Fluorescent Cholangiography?

If you have stones in the gallbladder you may require surgery to remove your gallbladder. That procedure is called Laparoscopic Cholecystectomy. 

Although the laparoscopic approach has been demonstrated to be very safe, complications may occur. In order to remove the gallbladder, the surgeon needs to identify a small duct (the cystic duct) that connects the gallbladder to the main bile duct. Once the duct is identified, the surgeon cuts the duct in order to completely remove the gallbladder. The bile duct can be misidentified in up to 0.4% of cases, and as a result, the main bile duct can be injured.

In the last few years a new technology has been developed to allow the surgeon to bettter visualize the ducts. It has been demonstrated that the surgeon can see 3-times better using a technology called near infrared guided (NIR) imaging using a special dye.

 
In order to better recognize the structures while operating, indocyanine green is intravenously administrated 45 minutes before the procedure starts. This is the time that is required in order for the dye to be excreted into the bile ducts. During the procedure, the surgeon uses a near infrared light to illuminate the extrahepatic biliary ducts.The dye that is in the extahepatic bile ducts glows when it is illuminated with near infrared light illuminating the ducts.