When   Thursday, November 5, 2009   Time   4:00 PM - 5:00 PM  
Where   Technological Instit M345 2145 Sheridan Rd.   map it
Audience   - Faculty/Staff - Student - Public
Contact   Virginia Lorenzo   847-491-5635  
Group   McCormick - Biomedical Engineering Department
More Info   http://www.bme.northwestern.edu

Tomasz Tkaczyk
Department of Bioengineering, Rice University

Through technology to new thinking toward development of modern bio-imaging devices

Our everyday reality is affected in its every aspect by the technology race. For example, today’s handheld communication devices incorporate computers more powerful than workstations from middle 90’s, integrate digital cameras using mega-pixel chips, and contain miniature imaging optics. In addition, through networking and the Internet these devices provide fast and easy access to countless resources of information. Consumer gadgets are not exclusive in this regard. Technology advancements come from and touch upon new engineering and research areas, enable design or manufacturing principles not possible just few years ago and create enormous research opportunities. In this exciting time for science and engineering, this dynamic progress is the context for my research program which is deeply immersed in new technology and focused on advancing miniature and unconventional optical sensing by developing state-of-the-art micro-fabrication methods and using all benefits of modern integrated electronics.

New technologies require also a new line of thinking.  One good example from my research area is optical microscopy. Classical microscopes are sophisticated imaging tools developed for high resolution imaging in multiple modes and serving various fields in research, industry, and education. However, microscopes first built for visual imaging have remained unchanged in their core principles since Robert Hooke’s (1635-1703) compound microscope. Recently digital microscopy started replacing visual observation with the introduction of new detectors and acquisition systems. To smooth this transition, microscopes preserved the original “visual” layout, retaining the majority of restrictions on their geometry and parameters. In consequence classical microscopes are large, expensive and inappropriate for many applications (such as point-of-care diagnostics, high throughput image cytometry, microarray imaging, telepathology, etc.). In contrast, digital miniature microscopes can use small-pixel image sensors and work at low magnification to deliver high-resolution, diffraction-limited images.  These systems can also draw upon inexpensive mass production techniques developed originally for electronics but usually not suitable for large-scale traditional optics. In addition, new fabrication methods applicable on the miniature scale can provide additional optical design freedom.  The small scale offers other benefits as well:  optical aberrations are less of a problem and, geometries such as arrays of miniature optics can be used to increase field of view at high magnification.

While rapid technology advances make our lives easier in some respects, our society faces numerous new challenges including growing healthcare costs and an increasing need for early medical diagnostics. Technology is at the frontier of addressing these issues. My research program joins this struggle through research on development of miniature and unconventional optics. It has to be noted that it is crucial to develop these systems fully optimized for a given application. This is because many research efforts are limited by the capabilities of commercial off-the-shelf (COTS) components for high performance imaging (e.g. GRIN lenses) or detection. COTS work demonstrates a principle but leaves a very wide gap to implementation even in an early clinical study.  By pushing the technology further, beyond COTS, it is possible to enable true translation “to the bedside.” Therefore in the background of my research program is to provide new imaging capabilities without sacrificing the intended, overall performance.

This presentation discusses modern technology challenges and benefits in context of optical instrumentation for biomedical applications. It provides a brief technology overview and discusses two very different applications enabled by the rapid technological progress.

I will first discuss my group’s research on development of miniature imaging systems for medical diagnostics and cost effective, high throughput optics. This is possible by creating and fusing state-of-the-art technologies in optics, opto-mechanics, electronics and software. Note that traditional optics fabrication techniques allow production of high performance optics (e.g., modern, high NA microscope objectives); such systems, however, are usually expensive and difficult for broad, high-volume implementation.  It is not trivial to develop cost effective, high performance miniature optical systems (like for example NA ³ 0.75).  Such development requires entirely new design and assembly approaches. My group works toward such a goal and I believe that if successful it can enable widespread application of miniature optics in medical diagnostics like cancer detection and point-of-care applications.

Next I will transition to my research toward development of new imaging modalities for multi-dimensional (3D+ data space) biological imaging.  I refer to this area as an indirect imaging because it often involves data post-processing. Note that traditional imaging usually directly yields an intensity distribution in the object I(x,y).  In biological imaging this distribution has been expanded by spectral information, i.e., one can obtain I(x,y,l) data. The spectral information provides crucial insight about bio-chemical processes occurring in the individual cells or tissue by allowing for multiplexed imaging that follows multiple molecules and their interactions. State-of-the-art systems (like confocal spectral imaging instruments from Zeiss or Nikon) are often based on sequential scanning and spatial image parameters (image sampling and resolution) are strongly related to imaging rate and/or photobleaching issues. To allow following of molecular events with finer temporal resolution and without artifacts, my lab focuses on developing snapshot techniques which can acquire an entire I(x,y,l) data set in a single, brief exposure. An example implementation of such a snapshot technique is the Image Mapping Spectrometer (IMS) for microscopy recently demonstrated in my lab and possible thanks to state-of-the-art fabrication techniques and modern electronics. The snapshot spectral imaging can be also crucial in numerous medical applications like neuron signaling or endoscopic in-vivo cancer imaging.