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Top > About Us > News Letter > Light as a Reliable Guide for Surgery

Light as a Reliable Guide for Surgery: Development of Hepatobiliary and Pancreatic Surgical Operation Using Fluorescence Imaging

From The University of Tokyo Hospital to the World
Hepatobiliary and Pancreatic Surgery / Artificial Organ and Transplantation Surgery Department

Kiyoshi Hasegawa, Professor and Chairman

1: Introduction

Textbooks of anatomy contain illustrations with fat removed and blood vessels colored in red and blue. What if cancers and vessels behind tissues could be visualized during surgical operations, thus enabling more reliable surgeries to be performed? This possibility motivated us to develop the technique of intraoperative fluorescence imaging. Our department has developed fluorescence imaging of the bile duct, liver tumors, and hepatic segments, and proactively applied this procedure to surgical operations since 2007.

2: Development of fluorescence cholangiography

Indocyanine green (ICG) is an agent that has primarily been used for liver functional tests. In the 1960s, ICG was already known to emit fluorescence peaking at approx. 840 nm when ICG bonded to protein was radiated with near infrared rays. We focused on this property and developed the technology known as fluorescence cholangiography, which enables visualization of the structure of the bile duct using light by directly injecting ICG into the bile duct, or by utilizing ICG that is excreted into bile after intravenous injection. [1] This technology has drawn particular attention for its effect of avoiding damaging the bile duct during laparoscopic cholecystectomy, one of the most commonly undertaken surgical procedures for gallstones and gallbladder polyps [2], and has been increasingly used in the U.S., Europe, and other regions.

3: Technology that enables liver cancer to emit light

In 2007, when our department was developing fluorescent cholangiography, we found that in addition to the bile duct, cancer tissue in the liver emitted intense fluorescence. [3] Our continued research uncovered the mechanism for this phenomenon, namely that ICG had accumulated inside and/or around the liver cancer following intravenous injection for preoperative liver function tests. [4] By applying this phenomenon to intraoperative imaging, it became possible to identify the location of tumors to be excised using light as a guide. Particularly during laparoscopic hepatectomy, a procedure proactively performed in our department in which an endoscope and rod instruments are inserted and removed through five or six holes in the abdomen, it is not possible for surgeons to confirm the presence of a tumor by directly touching the surface of liver, and therefore, this technology, which localizes cancer based on light emission, is useful to conduct rapid and reliable hepatectomies. [5]

4: Visualization of hepatic segments using light

In surgical operations to remove a liver tumor, it is important to completely excise the entire hepatic segment in which cancer is located rather than only scooping out the primary cancer, in order to avoid leaving behind micro cancerous tissues that expand around the primary cancer. Our department devises an accurate hepatectomy that matches the preoperative plan by distributing ICG throughout the hepatic segment to be excised (or the surrounding segments), and clearly visualizing the borders between the hepatic segments using fluorescence imaging. [6]

5: Efforts toward further enhancing the safety of pancreatectomy

In April 2016, laparoscopic pancreatectomy was included in the scope of insurance coverage. This procedure enables pancreatic surgeries that are usually complicated and involve high postoperative risks with only small surgical wounds. However, no effective solution has been established to prevent pancreatic fistula, the most critical complication associated with pancreatectomy, in which pancreatic juice leaks from the pancreatic stump and/or anastomotic part, resulting in severe damage to patient tissues. Our department is making continuous efforts to further enhance the safety of pancreatic surgery by applying ICG-based fluorescence imaging to the evaluation of organ blood flow around the pancreas, and by also developing a new fluorescence reagent to make pancreatic juice, which is normally colorless and transparent, emit light during surgery. [7]

6: Conclusion

In recent years, the development and clinical application of intraoperative fluorescence imaging has rapidly expanded. Last year, the Japanese Society for Fluorescence Guided Surgery (http://plaza.umin.ac.jp/jsfgs/index.html) (Japanese pages only) was established to provide a forum for information exchange across disciplinary borders. As the secretariat for JSFGS, our department undertakes continuous activities to promote information sharing among surgeons, researchers, and engineers.

1. Ishizawa T, et al. J Am Coll Surg 2008;208:e1-4.
2. Ishizawa T, et al. Br J Surg. 2010;97:1369-77.
3. Ishizawa T, et al. Cancer 2009;115:2491-504.
4. Ishizawa T, et al. Ann Surg Oncol 2014;21:440-8.
5. Kudo H, et al. Surg Endosc 2014;28:2504-81.
6. Yamashita S, et al. Br J Surg 2013;100:1220-8.
7. Miyata A, et al. J Am Coll Surg 2015;221:e27-36.

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