February 1, 2013 (Vol. 33, No. 3)
Rachit Mohindra Photometrics
Chris Ryan QImaging
New Imaging Systems Help Scientists Jump Hurdles in Biomedical Research
Single-camera, dual-modality imaging inventions—born out of a need for simplicity and affordability in the lab—are allowing biomedical researchers to track neural and cardiac activity in real time, opening the door to medical knowledge that benefits patients with life-threatening conditions such as arrhythmia, epileptic attacks, strokes, or even traumatic brain injuries.
Scientists have long relied upon low-light camera systems and specialized imaging techniques to further their understanding of diseases affecting the circulatory system and the nervous system. For example, electrophysiological imaging with fluorescent probes has yielded tremendous insight into the mechanisms of conditions such as arrhythmia. And in the field of neuroscience, scientists use high-end back illuminated optical imaging to track brain oxygenation, while lasers help create maps of blood flow in the brain.
Yet, for all of their advantages, these techniques also come with their own set of challenges. In traditional electrophysiological imaging, multiple cameras are required to carry out multiparametric imaging, making the setup not only costly, but also technically complex and difficult for scientists to perform. In neurological research, the use of the high-end, back-illuminated cameras limits scientists to measure just a single parameter at a time; an additional laser setup is required to accurately map out blood flow in the brain, increasing both the procedure’s cost and complexity.
Fortunately for frustrated scientists, relief has arrived in the form of independent efforts that have resulted in the development of dual modality within a single imaging system. Researchers at Oxford University and the University of Toronto have separately developed single-camera, multiparameter systems that are both scalable and less technically complicated, while also proving to be more cost effective and time efficient. In short, they have the potential to transform biomedical imaging.
In collaboration with Christopher Woods, M.D., Ph.D., a cardiac specialist at Stanford University, doctoral student Peter Lee at Oxford University studied cardiovascular disease and function using the first-ever in vivo, multiparametric electrophysiology imaging system.
Traditionally, arrhythmia mechanism studies are conducted on explanted hearts infused with saline solution—making it difficult to apply data to actual clinical settings. Imaging two key parameters for arrhythmia studies, cardiac action potentials (AP) and intracellular calcium transients (CaT), typically require separate camera setups. But using the Photometrics Evolve 128—a high-speed, high-performance EMCCD camera—and powerful LED chips, lenses, and filters, Lee and his colleagues were able to develop an efficient, single-camera-imaging and LED-illumination system. Their system successfully demonstrated simultaneous AP and CaT imaging of a mammalian heart in vivo, through 100 percent blood.
Meanwhile, Ofer Levi, Ph.D., of the University of Toronto, who researches biomedical sensing and imaging using photonic tools, has created his own custom imaging system. He’s combined QImaging’s Rolera EM-C2 EMCCD camera with a vertical-cavity surface-emitting laser (VCSEL) as the illumination source to create a system that allows scientists to use optical brain imaging as a low-cost, minimally invasive technique to record the responses of brain tissue to ischemia, a restriction in blood flow to the tissues. The single-camera, dual-modality approach allows Levi’s team to quantify flow changes in blood vessels while simultaneously measuring dynamics in oxygenation.
These innovative systems help lower lab costs, reduce technical challenges, and fast track biomedical research.
For more on in vivo imaging, be sure to check out “Improving In Vivo Small Animal Imaging“.