IMAGE-GUIDED SURGERY/FLUORESCENCE: Tool illuminates low-grade tumors

Sept. 1, 2012
In a pilot study, David Roberts, chief of neurosurgery at Dartmouth-Hitchcock Medical Center, operated on 10 patients with gliomas using a new tool designed to highlight the tumors.

In a pilot study, David Roberts, chief of neurosurgery at Dartmouth-Hitchcock Medical Center (Lebanon, NH), operated on 10 patients with gliomas using a new tool designed to highlight the tumors. Following the operations, a pathologist evaluated how accurately the probe had identified tumor tissue. The results are striking: Diagnoses based on fluorescence were accurate 64% of the time, but with the probe accuracy increased to 94%.1

The probe, which boosts fluorescence highlighting for tumors that are less metabolically active, represents a collaborative effort between the Norris Cotton Cancer Center and Dartmouth's Thayer School of Engineering. When the researchers first saw the results of using their fluorescing agent and probe on low-grade brain tumors, it was "jaw-dropping. The tumor glowed like lava," according to Keith Paulsen, professor of engineering.

Violet-blue and white light boosts fluorescence technique previously unable to highlight low-grade tumors. (Image courtesy of the Norris Cotton Cancer Center and Dartmouth College's Thayer School of Engineering)

The patients participating in the study had been given oral doses of the chemical 5-aminolevulinic acid (ALA) prior to their surgery. When metabolized, ALA produces the protein protoporphyrin IX (PpIX), which accumulates faster in tumor cells than healthy cells—and makes cancerous tissue fluoresce when exposed to blue light. Throughout the surgeries, Roberts used a microscope to see the fluorescence, and the new handheld probe to evaluate sections where fluorescence was not definitive.

The probe combines violet-blue and white light to simultaneously analyze both the concentration of PpIX and four other tumor biomarkers: PpIX breakdown products, oxygen saturation, hemoglobin concentration, and irregularity of cell shape and size. The probe reads how light travels when it hits the tissue, and sends this data to a computer. The computer runs it through an algorithm, and produces a straightforward answer as to whether the tissue is cancerous.

The Thayer/Norris Cotton/Dartmouth-Hitchcock team, which has been working on the brain probe for about six years in collaboration with scientists from the University of Toronto, built on research conducted in Germany about 15 years ago.

The brain probe may have applications for other cancers as well; a protocol is already in place for a similar study on lung cancer tumors.

1. P.A. Valdes et al., J. Biomed. Opt., 16, 11, 116007 (2012).

Sponsored Recommendations

Achromatic Lenses: High-Quality Custom Optics

March 13, 2025
Ensure clarity and accuracy in your optics systems with Lacroix’s achromatic lenses. Explore how our custom solutions minimize chromatic aberration for perfect results.

Manufacturing Considerations for Tolerancing Aspheres

March 13, 2025
Understand the critical factors in manufacturing aspheres and how Lacroix Optics ensures precise tolerancing in every optical component.

Explore Our Videos: Insights into Precision Optics

March 13, 2025
Get an inside look at Lacroix Optics with our collection of informative videos showcasing our capabilities, innovations, and processes.

Optical Assemblies: Reliable and Precise Solutions

March 13, 2025
Ensure your optical system works seamlessly with Lacroix Optics' custom optical assemblies. Discover the precision and reliability we bring to every project.

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!