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Dr. Witte's experimental ultrasound laboratory develops new imaging tools and techniques that employ a combination of light, sound, and radiofrequencies to image deep into tissue with novel contrast mechanisms. This translational technology potentially impacts a variety of medical disorders ranging from epilepsy to cancer.
In cancer related research, Dr. Witte exploits photoacoustic imaging, which combines light with sound to produce high resolution ultrasound images based on the optical absorption properties of tissue. He is also interested in collaborating with others to develop smart contrast agents capable of targeted imaging, therapy and more.
In addition to the cancer imaging program, Dr. Witte is also part of the Neuroscience, Applied Mathematics and Biomedical Engineering graduate programs.
Although conventional ultrasound imaging exhibits deep penetration with excellent spatial resolution, the modality suffers from poor contrast in soft tissue. Dr. Witte's Experimental Ultrasound and Neural Imaging Laboratory strives to overcome these limitations by combining ultrasound with other forms of safe energies (e.g., light, electricity, and microwaves). These noninvasive techniques enable deep imaging of optical absorbers in tissue (photoacoustic imaging), volumetric mapping of current source densities (acoustoelectric imaging), and quantifying mechanical properties in normal and diseased human tissue in vivo (elasticity imaging). For cancer imaging, these methods open the door for a new frontier to visualize anatomical and functional features inside the body, while pushing the limits of spatial and temporal resolution. They develop unique imaging systems (hardware and software) that can be applied to both small animals and humans. For example, they recently patented and licensed a photoacoustic flashlight adapter that can be attached to virtually any commercial linear ultrasound array to enable photoacoustic breast imaging for detection of blood vessels (angiogenesis) and other indicators of breast cancer.
They also develop and test smart contrast agents that can be used for both molecular imaging and therapy, which is a primary topic in a “Drug Discovery and Contrast Agent” class Dr. Witte co-teaches to graduate students (primarily cancer biology and biomedical engineering). They are also currently developing microwave-induced thermoacoustic imaging for breast cancer detection combined with focused microwave therapy as a noninvasive alternative to surgery for treating early-stage breast cancers. Most of these technologies can be translated to the clinic and potentially offer better sensitivity and specificity with fewer side effects and lower cost.
Specific to the University of Arizona Cancer Center, Dr. Witte's group has published several papers describing in vivo photoacoustic imaging and spectroscopy (PAIS) of prostate, pancreatic and colon cancer with high frequency pulse echo ultrasound using various mouse models. They were the first group to develop a combined high resolution system (ultrasound + PAIS) for multimodality in vivo imaging of prostate cancer invasions adapted for the window chamber model (Bauer et al. 2009).
Dr. Witte also contributed to a review paper on Cancer Metastasis and Lymphangiogenesis (“future directions in ultrasound and photoacoustic imaging for early cancer detection, molecular imaging, and tracking metastasis”) in Surgical Oncology (Roach 2011 et al.). More recently, they described the photoacoustic flashlight adapter in Physics in Medicine and Biology (Montilla et al. 2013) that has since been patented and licensed by Zonare Medical Systems for human breast imaging. They have also published on carbon nanotubes as a contrast agent for spectroscopic microwave-induced thermoacoustic imaging (Bauer et al. 2014). A few of his key collaborators are Art Gmitro PhD (Medical Imaging), Bhaskar Banerjee MD (Gastroenterology), Marisa Borders MD (Medical Imaging), and Leigh Neumayer MD (Surgery). Dr. Witte looks forward to working with these top-notch collaborators for years to come.