Researchers develop new imaging technology for cancer detection
Richard Riman, a distinguished professor in the Department of Materials Science and Engineering at Rutgers, makes dust.
This dust is made of rare-earth nanoparticles. Its infrared emissions will help detect cancer in its early stages through a process called optical imaging, Riman said.
A team consisting of University faculty members in multiple disciplines and students of all levels has been developing this new imaging technology since 2008, said Prabhas Moghe, a distinguished professor in the Department of Chemical and Biochemical Engineering.
Originally funded by the National Science Foundation, the team has shown promising results that were published in Nature Communications, a multidisciplinary natural sciences research journal.
The team was also recently awarded $2 million by the National Institute of Biomedical Imaging and Bioengineering, he said.
Infrared lights exist beyond the red end of the visible spectrum due to their greater wavelength, said Mark Pierce, an assistant professor in the Department of Biomedical Engineering.
On the other end of the spectrum are lights that have shorter wavelengths than blue light, including ultraviolet and X-rays.
The new technology is mainly concerned with near-infrared light and shortwave infrared light, said Pierce, an expert in optical imaging.
Rare-earth particles emit infrared light when illuminated by light with wavelengths just between near-infrared and shortwave infrared, Riman said.
The general principle of the research is to use these particles as contrast agents that will show on images to help researchers locate where diseases are in the body, Pierce said.
“We can create enough light from those particles that we can see it in a camera that captures those photons and transmits them into visible radiation,” Riman said.
A similar idea is also used in magnetic resonance imaging, but the novelty of the research comes with the use of infrared light because it can go through the human body without being absorbed, Pierce said.
Longer wavelengths go deeper into tissue than shorter ones do, he said. Visible wavelengths of light do not have this property.
“Our vision for the future is to image cancer and other diseases without opening up the patients, which is what they do now,” Riman said.
Safety and low cost are big advantages of infrared scans compared to computerized tomography, X-ray radiography and positron emission tomography scans that uses radioactive substances, he said.
A green-colored light is used, he said. Human eyes are sensitive to this wavelength.
“The wavelength we use for those particles to emit light is almost the same [as] the wavelength you use for your TV remote control,” he said. “It is an eye-safe wavelength.”
The immense radiation patients receive from CT and PET scans also makes infrared a more appealing choice, he said. Researchers can create energy sources for infrared light inexpensively compared to traditional equipment that easily exceeds $1 million.
Shortwave infrared light already has multiple military applications where special cameras are used to capture this range of wavelengths, Riman said.
“The Army uses SWIR because they can easily see through dust storms or underwater, but the question is, could you also see through the body?” he asked. “Here, [a] military application has actually led to what might be a really outstanding visualizing approach for diseases.”
Researchers send the rare-earth particles into cancerous regions of laboratory mice by encapsulating a collection of particles in an albumin protein shell.
According to albumin.org, albumin is the name for a series of serums used to treat injuries.
“Naked rare-earth [particles] alone do not disperse in blood,” Moghe said.
Protein shells can accumulate in cancerous regions through two methods, he said. In passive mode, proteins of the right size accumulate through a process called the enhanced permeability and retention effect.
This method studies cancer cells taking in oxygen and other nutrients from the blood supply, he said.
“The blood vessels are more leaky near the mass of cancer cells,” he said. “Therefore, particles with certain sizes will leak through [the blood vessels] and get trapped in the cancer region.”
A more proactive approach binds proteins with rare-earth particles to cancer cells, he said. Small tags such as antibodies are added onto these protein shells so that they have an affinity to proteins on the cancer cells.
The new imaging technology is potentially important in the detection of breast cancer, Moghe said. The research team is looking to track the spread of cancer cells before tumors form and to track metastases after removing tumors.
Metastatic cells are cancer cells that spread from the primary location to other parts of the body, Pierce said. With breast cancer, they can spread to the lymphatic system.
“What surgeons currently do is to chop off lymph nodes one after another [and] send [them] to the lab, until they reach one that does not contain cancer cells,” he said. “They can conclude that the cancer spreads no further than this one.”
This long and expensive process removes tissues vital to the function of patients’ bodies, he said.
The new technology enables surgeons to diagnose quickly by using a camera that detects infrared emission from lymph nodes, he said. It can potentially detect breast cancer in an early stage, before tumors grow large enough to be picked up by current technologies.
The project has seen breakthroughs in cancer detection and is envisioning more for the future, Moghe said.
“We are also looking into other applications of the technology besides breast cancer, such as imaging blockages in heart diseases,” he said.
The project has provided immense opportunities for Rutgers students of all levels, Riman said. Advanced instrumentation allows students to learn techniques not even people who have been in the field for decades get their hands on.
“It will take at least three to five years to get the technology to the clinic, and students will continue to enjoy this educational opportunity,” Moghe said. “Before then, we will keep optimizing brightness, aiming for deeper detection [and] simplifying imaging equipment.”