Dr. Robert Chang of the Department of Mechanical Engineering has been awarded a grant from the National Institute of Standards and Technology (NIST) to develop a standard calibration tool for depth-resolving optical imaging modalities. Optical imaging devices can produce much higher resolution images than MRI or CT scans, but they are generally inferior for applications that require higher depth penetrations. However, a number of recent advancements in optical imaging techniques are able to improve the ability of light to propagate through tissues with diffraction-limited beam qualities. This opens up the possibility of accurate high resolution, depth-resolving optical imaging. Dr. Chang’s Biomodeling and Biomeasurement Lab at Stevens is working to advance this promising technology with a standard calibration tool so that new optical imaging devices can be applied to measure depth with precision in clinical settings.
“Early diagnosis can make a tremendous difference in the effectiveness of treatment for many diseases,”says Dr. Michael Bruno, Dean of the Charles V. Schaefer, Jr. School of Engineering and Science. “Continued innovation in medical imaging technologies can thus have an impact on the health of millions.”
"Providing accurate depth resolution standards will ensure confidence in high resolution medical imaging modalities capable of detecting tumors at much earlier stages of development," says Dr. Frank Fisher, Interim Director of the Department of Mechanical Engineering. "These standards are crucial for the establishment of cross-validated optical measurements necessary for future technological innovation in the screening and diagnosis of many human disease states."
Just as there is a need to routinely zero a scale for quantitative weight measurements, scientists need to calibrate microscopes so that they can produce accurate and precise spatial measurements. Established standards have made lateral optical imaging devices extremely precise, widely accepted clinical tools, but axial (depth) optical imaging devices have no widely accepted standard. Dr. Chang has therefore proposed the design and fabrication of a tissue phantom (or tissue-simulating object) to serve as a test target for the calibration of promising depth-resolving optical imaging modalities including optical coherence tomography (OCT) .
The establishment of a calibration standard is crucial for fields like ophthalmology, in which quantitative thickness measurements of reflective eye tissue layers using OCT can aid the diagnosis and treatment of numerous diseases. Doctors can use OCT to get cross-sectional image of retina and look for microstructural abnormalities down to the micron scale. Doctors can also check the size and shape of the cornea to determine if a patient is a good candidate for Lasik surgery.
Micron-scale depth imaging with OCT can also help in the study of certain cancers. Materials have different refractive indexes and scatter light differently. Doctors know how cancer cells and healthy cells differ in reflective index, so they can use OCT to detect cancerous cells. Endoscopic-based OCT has also been used to study the initial stages of the invasion of mucosal layers into submucosal layers of the gastrointestinal lining, which can be an early indicator of colon cancer. The same principle can also be applied for earlier detection of atherosclerosis, a risk factor for heart attacks in which fatty material accumulates on blood vessel walls. The fatty materials begin to cause protrusions at minute scales, and OCT can detect these abnormalities at early stages.
Robert Chang received his B.S. from The University of Pennsylvania and Ph.D. in Mechanical Engineering from Drexel University with a research focus in computer-aided tissue engineering. His doctoral dissertation centered on the development of biofabrication systems to create reproducible, biomimetic 3D micro-organs as a high-throughput in vitro radiation/drug model for NASA's exploration in planetary environments.
He received a National Research Council (NRC) Research Fellowship to work as a biomechanical engineer in the Physical Measurement Laboratory at the National Institute of Standards and Technology (NIST) where he has engineered novel tissue models towards the validation of depth-resolving optical modalities including optical coherent tomography (OCT) and confocal microscopy for dimensional metrology as well as hyperspectral imaging for wound healing applications and surgical scenes. Robert is currently an Assistant Professor in the Mechanical Engineering Department at Stevens where his research interests are in biofabrication, biomodeling, and measurement of biotissues.
About the Department of Mechanical Engineering
The Department of Mechanical Engineering confidently addresses the challenges facing engineering now and into the future, yet remains true to the vision of the founders of Stevens Institute in 1870 as one of the first engineering schools in the nation. The department mission is to produce graduates with a broad-based foundation in fundamental engineering principles and liberal arts together with the depth of disciplinary knowledge needed to succeed in a career in mechanical engineering or a related field, including a wide variety of advanced technological and management careers.
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