Researchers have used a Scanning Fiber Endoscope (SFE) to detect the glow produced by adding the pro-drug 5-ALA to experimental models of malignant brain tumors.
Research by Barrow Neurological Institute physicians and University of Washington scientists on novel imaging technology for malignant brain tumors was published in the April issue of World Neurosurgery. The research was conducted by Drs. Evgenii Belykh and Mark Preul at the Barrow Neurological Institute Neurosurgery Research Laboratory with technology developed by Drs. Eric Seibel and Leonard Nelson from the Department of Mechanical Engineering and the Human Photonics Laboratory at the University of Washington. SFE allows the neurosurgeon to visualize the fluorescent light produced by 5-ALA earlier and for longer periods of time than visually possible with a standard operative microscope. SFE offers sufficient image resolution to observe individual brain and tumor cells and the scanning feature reduces the photobleaching of the fluorescent signal which can be problematic in the operating room.
The SFE scope uses low-power laser light that is scanned with an actuator at the tip of a highly flexible shaft with overall diameter about the thickness of a nickel. For surgical guidance, two modes of imaging are generated concurrently at video rates, fluorescence to see the tumor, and reflectance imaging to see the surgical field and the surgical tools. Drs. Seibel and Nelson commented, "The combination of high sensitivity and long viewing time of the fluorescently-labeled cancer should allow the guidance necessary for more complete tumor margin clean-up."
The research was funded by NIH R01 EB016457, PI-Seibel, Advanced biophotonics for image-guided robotic surgery, the Barrow Neurological Foundation, and the Newsome Chair in Neurosurgery Research held by Dr. Preul. Barrow is part of Dignity Health St. Joseph's Hospital and Medical Center in Phoenix. The UW SFE technology is licensed and commercial prototypes are undergoing pre-clinical trial evaluations. Preliminary SFE imaging studies using tissue penetrating near-infrared (NIR) targeting agents have demonstrated excellent tumor contrast in animal models. Barrow and the University of Wisconsin plan to expand their collaboration into improved tumor resection using the SFE and NIR agents.