Tissue from a patient diagnosed with low-grade glioma. The green image is taken with the new method, while the pink uses conventional hematoxylin and eosin staining. Going from the upper left to the lower right, both images show increasing cell density due to more tumor tissue. The insets reveal the high density of tumor cells. Credit: N.V. Kuzmin et al, VU University Amsterdam
Knowing the boundary of a tumor, particularly around important anatomy as in the brain, is critical to successful surgical extractions. Tumors in situ typically look just like healthy tissue, so during surgery small samples are sent to the path lab for frozen section, where pathologists stain them and analyze under a microscope.
Scientists at the VU University Amsterdam, The Netherlands may have come up with a way to identify the margins between healthy and cancerous tissue during the surgery, requiring no biopsies or staining of the tissue. The technique relies on very short burst lasers that use what’s known as third harmonic generation to essentially fuse photons within tissue to generate higher frequency photons that reveal a lot about their environment.
The laser light is delivered at 1200 nanometers, long enough to penetrate a bit through soft tissue. When three photons combine they produce new photons at 400 nanometers that scatter as they pass through the tissue on the way to the detector. The scattering creates a picture of the tissue, allowing for identification of cancerous vs. healthy material.
Study in Biomedical Optics Express: Third harmonic generation imaging for fast, label-free pathology of human brain tumors…
Via: The Optical Society…