Laser-based Tool Allows Surgeons to See Where Tumor Ends, Brain Begins

A new laser-based technology allows surgeons to delineate between brain and cancer tissue on a microscopic level while they are operating.

Used to distinguish between healthy tissue and a tumor in the brains of living mice, the researchers prove in their latest study that the new technique is equally effective in tissue removed from a patient with glioblastoma multiforme, one of the deadliest brain tumors.

According to a study published last fall in the Journal of Neurosurgery, patients diagnosed with glioblastoma multiforme on average are given 18 months to live after diagnosis. And while surgery is one of the most effective treatments for this kind of tumor, less than a quarter of those operations performed to counteract it achieve the best possible results.

"Though brain tumor surgery has advanced in many ways, survival for many patients is still poor, in part because surgeons can't be sure that they've removed all tumor tissue before the operation is over," co-lead author Dr. Daniel Orringer, a lecturer in the University of Michigan Department of Neurosurgery, said in a statement. For this reason, Orringer argues that better tools designed to help surgeons visual the tumor during surgery are needed.

The new approach, called SRS microscopy, achieves this through the detection of a weak light signal that comes out of the differing materials after they are hit with light from a non-invasive laser, revealing their chemical signatures. By amplifying this signal by more than 10,000 times, the researchers have discovered a way to make live multicolor SRS images of living tissue or other materials.

As a result, the researchers explain in their new study, they are able to use the technique to discover a tumor's "margin," or where it ends and the healthy cells begin.

"Biopsy has been the gold standard for detecting and removing these types of tumors," said Sunney Xie, a professor of chemistry and biology at Harvard University and the senior author of the paper. "But this technique, we believe, is better because it's live. Surgeons can now skip all the steps of taking a biopsy, freezing and staining the tissue -- this technique allows them to do it all in vivo."