Brain surgery is famously difficult for good reason: When removing a tumor, for example, neurosurgeons walk a tightrope as they try to take out as much of the cancer as possible while keeping crucial brain tissue intact - and visually distinguishing the two is often impossible. Now researchers report they have developed an imaging technology that could provide surgeons with a color-coded map of a patient's brain showing which areas are and are not cancer. The research was published in the journal Science Translational Medicine.
First developed in the early 1990s for imaging the retina, optical coherence tomography (OCT) operates on the same echolocation principle used by bats and ultrasound scanners, but it uses light rather than sound waves, yielding a higher-resolution image than does ultrasound. One unique feature of OCT is that, unlike X-ray, CT scans or PET scans, it delivers no ionizing radiation to patients. The past decade, research groups around the globe have been working to further develop and apply the technology to other organs beyond the relatively transparent eye. Now it might provide a solution to the problem of separating brain cancers from other tissue during surgery.
The researchers first built on the idea that cancers tend to be relatively dense, which affects how they scatter and reflect lightwaves. The team tried for three years to build their technique on this principle. Eventually, the researchers figured out that a second special property of brain cancer cells - that they lack the so-called myelin sheaths that coat healthy brain cells - had a greater effect on the OCT readings than did density.
Once they had found the characteristic OCT "signature" of brain cancer, the team devised a computer algorithm to process OCT data and, nearly instantaneously, generate a color-coded map with cancer in red and healthy tissue in green. The researchers envision that the OCT can be aimed at the area being operated on, and the surgeon can look at a screen to get a continuously updated picture of where the cancer is and isn't.
So far, the team has tested the system on fresh human brain tissue removed during surgeries and in surgeries to remove brain tumors from mice. The researchers hope to begin clinical trials in patients this summer.
The system can potentially be adapted to detect cancers in other parts of the body, as well. The researchers are working on combining OCT with a different imaging technique that would detect blood vessels to help surgeons avoid cutting them.
Based on material originally posted by Johns Hopkins Medicine.