NPRE Associate Prof. Ling-Jian Meng’s team is developing a new, non-invasive X-ray imaging technique, called X-ray stimulated emission tomography (XSET), for mapping the distribution of trace metals in mouse brain. The new technology could provide critical information for studying the relation between the presence of trace metals in the brain and certain neural degenerative diseases, such as Alzheimer’s and Parkinson’s diseases, as well as provide a more precise way for image-guided anti-cancer drug delivery and release processes.
The National Institute of Health recently granted $1.9 million to a team of researchers that Meng and Patrick J. La Riviere from the University of Chicago lead to develop a state-of-art X-ray imaging facility that allows detailed mapping of naturally occurring trace metals in biological samples. "Several research teams have indicated that the abnormal presence of certain trace metals could be correlated to the onset of Alzheimer’s and Parkinson’s diseases," Meng said, "However, at this point, most methods allowing for mapping of trace metals only work with excised tissue samples.
“The trace metals in the brain are radioactively stable, so they do not radiate signals,” he explained. Meng’s approach is to shoot a beam of x-rays into the object to stimulate the metal to radiate fluorescence X-rays. By collecting the fluorescence X-rays with dedicated X-ray cameras, one could form 3-D tomographic mapping of the trace metal in intact biological samples. This technique would therefore have the potential of allowing in vivo imaging of trace metals in mouse brain.
To conduct the work, Meng and his students will build a one-of-a-kind imaging facility that consists of four different x-ray sources, a wide array of advanced x-ray detectors for X-ray imaging and spectroscopy measurements, an optical photon imaging camera based on state-of-art intensified EMCCD detectors, and an emission tomography system integrated ion beam line. This facility will allow Meng’s team to image biological objects using a broad spectrum of electromagnetic radiations, ranging from optical photons to energetic gamma rays.
The facility is expected to be available within the next year, and would offer a highly unique X-ray imaging capability for a wide range of biomedical imaging applications.
The new X-ray facility would also allow Meng’s team and his collaborators to study X-ray induced/modulated anti-cancer therapeutic techniques. With the strong X-ray beam tuned at specific X-ray energies, one could selectively stimulate a micro-area around or inside a tumor tissue. This stimulation could trigger local therapeutic effect by releasing anti-cancer drugs carried to the target by specifically engineered nano-particles.
“With the bench-top system, we can focus the beam to stimulate an area as small as 30 microns in diameter,” Meng said. “By working with Dr. Leuwei Lo’s group at the University of Chicago, we plan to explore a combined X-ray induced photodynamic therapy (PDT) and localized X-ray imaging strategy that could allow researchers to visualize the exact therapeutic delivery process, and potentially visualize the inhomogeneous response of the tumor to the treatment."
In addition to providing a new path for radiological research, Meng plans to use the setup as a teaching facility for the current NPRE 435 Radiological Imaging course, and create a new course, NPRE 436, Radiological Imaging Lab. The new course would begin in Fall 2015, according to the plans.
Meng’s group is collaborating with several groups from the University of Chicago and Northwestern University on building the new facility and on several biomedical applications. While the Illinois team is building the imaging hardware, the University of Chicago team is developing image-processing software and the X-ray induced photodynamic therapy approaches. The Northwestern team is examining various applications for the device.