The use of new optical coherence tomography (OCT) technology may more accurately distinguish between brain tumor cells and healthy brain tissue, enabling more thorough removal of brain tumor without damaging normal brain cells, a new study suggests.
“This new technology can distinguish what is cancer and what is normal brain tissue better than anything else we have. We are finally cracking the code,” lead investigator Alfredo Quinones-Hinojosa, MD, professor of neurosurgery, neuroscience and oncology at the Johns Hopkins University School of Medicine, Baltimore, Maryland, told Medscape Medical News.
With current technology it is difficult to distinguish between cancer cells and normal brain cells, particularly at the edge of the tumor, he added.
“It is not like in other areas on the body where extra tissue can be taken to be on the safe side. You can’t do this in the brain. We obviously do not want to remove healthy brain cells, as this could compromise speech, motor and cognitive function. So we end up leaving parts of the tumor in. With OCT we can be much more accurate.”“It has recently been shown that 70% of a brain tumor needs to be removed to have an effect on survival, and survival improves with every extra 5% of tumor removed. Our results suggest this new technology should enable up to 95% of the tumor to be removed, which could have dramatic effects on survival,” lead author and medical student, Carmen Kut, told Medscape Medical News.
The technology was developed by a group led by Xingde Li, PhD, professor of biomedical engineering at Johns Hopkins. He explained that the OCT technology provides direct visual guidance to the surgeon in the intraoperative setting. “It works like ultrasound but uses light instead of sound to give a picture of the tissue.”
“At present a preoperative MRI shows the position of the tumor but the brain shifts during surgery so there is some uncertainty about the exact limits of the cancerous tissue. Microscopes can also be used during surgery but these only show the surface appearance of the tissue.
“The OCT technology is used in real time during the surgery — by pointing the probe at each individual piece of tissue it detects which tissue is cancerous and needs to be removed and which is normal so can be left in. The results are shown in a real time coloured map, with red signaling cancer and green signaling healthy cells,” he added.From these findings they calculated the optical attenuation coefficient — a measure of how much light from the probe is absorbed or reflected in a particular tissue — and how this differs for cancer cells and healthy cells.