An optics technique can show the precise location of tumors in the brain and produce images in less than a minute, researchers at VU University Amsterdam, Netherlands discovered.

The technique uses short laser pulses directed into the tissue, and when three photons converge at the same time and place, the photons will interact with tissue in the brain, and the interaction will result in a single photon.

The incoming photons have a wavelength of 1,200 nanometers, long enough to penetrate deep into the tissue, and outgoing photons have a wavelength of 600 or 400 nanometers, according to the study. The shorter wavelengths mean that the photons can scatter in the tissue and reveal what the tissue looks like inside.
“The used laser powers have been shown to be safe, and in principle, can be used with any disease with a change in cell or tissue morphology,” Dr. Marloes Groot of VU University Amsterdam, Netherlands, told HCB News.

A staining method, which uses chemicals like hematoxylin and eosin, is sometimes used to turn different tissues blue and red, revealing their structure so pathologists can see if there are any tumor cells. However, that process can take up to 24 hours to be conclusive, which means that surgeons may perform the surgery and not even realize that there is still some cancerous tissue left in the brain.

Other scientists have used the laser technique for other applications, such as making images of insects and fish embryos, but this is the first time it has been used to analyze brain tumors, and the images were just as good, if not better, than the conventional staining method, according to the study. Brain tumors are particularly deadly since surrounding brain tissue is damaged extensively by surgery, chemotherapy and irradiation.

The technique was tested on samples of glial brain tumors from humans. Smaller images took less than one second to make and larger images of a few square millimeters took five minutes. Most images were taken in less than a minute. “This makes it possible to do it in real time in the operating room,” said Dr. Groot.

The researchers are using the laser to conduct a study on breast tumor detection and on tumor cells in lymph nodes, said Dr. Groot, both to improve surgical results and after surgery, to quicken the process to starting treatment.

Additionally, a hand-held device is being developed so a surgeon can use the device to identify a tumor’s border during surgery. Since the pulses can only reach about 100 micrometers into the tissue, a needle that can pierce the tissue and deliver the photons deeper might be used. “Building a complete prototype for a handheld device will take one to two years and then we can start a small clinical study for testing the device in the operating room,” Dr. Groot added.

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