What is Fluorescence Guided Surgery?

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

1. Fluorescent Dye: The most commonly used fluorescent agent is Indocyanine Green (IGC), though a number of other application-specific dyes are being actively developed around the world, such as OTL38 for cancer surgeries.

2. An Excitation Source: The fluorescent dyes used in FGS are excited by a light source that emits light in very specific near-infrared wavelengths which will cause the dye to fluoresce (or ‘glow’) and highlight the target structure.

3. A Detection Technique: The near-infrared spectrum of light that FGS dyes operate in is not visible to the human eye. It is, however, able to be seen through the use of special cameras and light filters which can detect the near-infrared fluorescence and display it on a screen for the real-time use by the surgical team.

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 Contrast agent Status
Sentinel lymph node mapping Breast cancer Indocyanine green (ICG) (3437) Clinical
Methylene blue (MB) (38, 39) Clinical
  Melanoma ICG (40, 41) Clinical
  Head and neck cancer ICG (42) Clinical
  Lung cancer ICG (43) Clinical
  Esophagus cancer ICG (44, 45) Clinical
  Gastric cancer ICG (46, 47) Clinical
  Colorectal cancer ICG (48) Clinical
  Anal cancer ICG (49) Clinical
  Prostate cancer ICG (5052) Clinical
  Penile cancer ICG (51, 52) Clinical
Lymphography Lymph flow ICG (5355) Clinical
Angiography Cerebral aneurysm Fluorescein sodium (5658) Clinical
  Coronary artery bypass grafting ICG (59, 60) Clinical
  Abdominal aortic aneurysm ICG (61) Clinical
  Abdominal surgery ICG (62, 63) Clinical
  Reconstructive surgery ICG (6470) Clinical
Anatomic imaging Cholangiography ICG (71, 72) Clinical
  Pancreas MB (73) Preclinical
T700-F (74) Preclinical
  Ureters MB (75) Preclinical
  Nerves Various fluorescently labeled peptide (NP) (76, 77) Preclinical
  Parathyroid and thyroid grands T700 and T800 fluorophores (78) Preclinical
  Endocrine grands Various near-infrared fluorophores (7981) Preclinical
Tumor imaging Malignant glioma 5-ALA (8286) Clinical
  Fluorescein sodium (8789) Clinical
  BLZ-100 (90) Clinical
  GB119 (91) Preclinical
  Brain metastases Fluorescein sodium (92, 93) Clinical
  Head and neck cancer IRDye800CW conjugate (94, 95) Clinical
IRDye700DX conjugate (96) Clinical
  Hepatocellular carcinoma ICG (97100) Clinical
  Liver metastases ICG (99) Clinical
  Breast cancer MB (101) Clinical
    EC17 (102) Clinical
    IRDye800CW conjugate (102) Clinical
    LUM015 (103) Clinical
    AVB-620 (104) Clinical
  Lung and chest masses ICG (105) Clinical
  Folate-fluorescein isothiocyanate (FITC) (106) Clinical
  EC17 (107) Clinical
    OTL38 (108) Clinical
  Ovarian cancer ICG (109) Clinical
    Folate-FITC (28) Clinical
    EC17 (110) Clinical
    OTL38 (111) Clinical
    gGlu-HMRG (112) Preclinical
  Pancreatic cancer Green fluorophore conjugate (113, 114) Preclinical
    IRDye800CW conjugate (102) Preclinical
  Insulinoma MB (73) Preclinical
  Solitary fibrous tumor (pancreas) MB (115) Preclinical
  Renal cell carcinoma EC17 (116) Clinical
    OTL38 (102) Clinical
  Bladder cancer 5-ALA/HAL (117120) Clinical
  Prostate cancer ICG conjugate (121) Preclinical
    5-ALA (122) Clinical
  Gastric cancer ICG (123125) Clinical
  Colorectal cancer Green fluorophore conjugate (113) Preclinical
    IRDye800CW conjugate (126) Clinical
    gGlu-HMRG (127) Preclinical
  Basal cell carcinoma 5-ALA (128) Clinical
    GB119 (129) Preclinical
  Sarcoma LUM015 (103) Clinical
  Parathyroid adenoma MB (130) Clinical
Laparoscopic- and robotic-assisted surgeries Nephrectomy ICG (131) Clinical
  Cholecystectomy ICG (72, 132) Clinical
  Esophagectomy ICG (133) Clinical
  Gastrectomy ICG (134) Clinical
  Adrenalectomy ICG (135, 136) Clinical
Fluorescence endoscopy Brain aneurysm ICG (137139) Clinical
  Endonasal surgery ICG (140142) Clinical
  Angiography ICG (142, 143) Clinical
  Brain tumor ICG (140, 144, 145) Clinical
  Head and Neck tumor ICG (146) Clinical
  Gastric cancer ICG (123125) Clinical
Marking tumor Colonic tattooing ICG (147149) Clinical