New technique identifies tumors in real time in the operating room -
Before they excising a tumor, surgeons need to determine exactly where the cancer cells find. Now, research published today (OSA) The Optical Society journal Optics Letters describes a new technique that could give surgeons cheaper and lighter tools, such as glasses or handheld devices , to identify tumors in real time in the operating room.
new technology, developed by a team from the University of Arizona and Washington University in St. Louis, is a dual-mode imager that combines two imaging fluorescent near-systems infrared to detect cancer cells labeled and imaging reflection of visible light to see the contours of the tissue itself, in a small lightweight body about the size of a quarter in diameter, just 25 millimeters in diameter .
"dual modality is the way to go because it has significant advantages over single modality," says the author Rongguang Liang, associate professor of optical sciences at the University of Arizona.
interest in the multi-modal imaging technology has surged over the past 10 years, said Optics Letters news editor Brian Applegate of Texas A & M University, who was not involved in the research. People realized that to better diagnose diseases such as cancer, he said, you need information from a variety of sources, either fluorescence imaging, optical imaging or biochemical markers .
"By combining different methods together, you get a much better picture of the fabric," which could help surgeons make sure they remove every bit of the tumor and the least amount of healthy tissue that possible, says Applegate.
Currently, doctors can inject fluorescent dyes into a patient to help identify cancer cells. the dyes converge on diseased cells, and when doctors shine a light of particular wavelength on the cancerous area, the dye glows. in the case of a common dye called indocyanine green (ICG), it shines in the near-infrared light. But because the human eye is not sensitive near infrared light, surgeons must use a special camera to see the light and to identify the precise location of the tumor.
Surgeons must also be able to see the surface of the fabric and the tumor below prior to cutting away, which requires the imaging of visible light. Thus, researchers have developed systems that can see in both visible and fluorescent lighting modes.
The problem is that both modes have opposite needs, making integration difficult. Because the fluorescent glow tends to be low, near-infrared light camera needs to have a large opening to collect as much fluorescent light as possible. But a camera with a wide aperture has a shallow depth of field, which is the opposite of what is needed for imaging visible light.
"The other solution is to put two different imaging systems together side by side," Liang said. "But it makes the device bulky, heavy and not easy to use."
To solve this problem, the group of Liang and that of his colleagues, Samuel Achilefua and Viktor Gruev at Washington University in St. Louis, created the first of its kind imaging system bi- mode that makes no sacrifices.
The new system is based on a simple opening of filter consists of a disc-shaped area in the middle and a Ring- shaped area outside. The central zone allows the visible light and near infrared, but the outer ring does not allow near-infrared light. When you place the filter in the imaging system, the opening is wide enough to let in a lot of near-infrared light. But since visible light can not penetrate the outer ring, the visible-sensitive part of the filter has a relatively small opening that the depth of field is large.
Liang team is now adapting its filter design for use in devices like light spectacle that a surgeon can wear while running. They also develop a similar portable instrument.
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