Paul Vaska

Research Interests

Non-invasive imaging techniques have undergone substantial growth in recent years, in both the research and clinical arenas. The standard anatomical imaging modalities of computed tomography (CT) and magnetic resonance imaging (MRI) have been complemented by quantitative functional approaches like positron emission tomography (PET) and single photon emission computed tomography (SPECT). Our lab develops new instrumentation and processing techniques to enhance the functional capabilities of PET, and also to combine it with synergistic modalities such as MRI to provide unprecedented, multidimensional information for broad applications ranging from the traditional areas of cancer diagnosis and brain research to plant science with the aim of developing improved biofuels. We have developed a miniaturized brain scanner for rodents (RatCAP) which avoids the potentially confounding effects of general anesthesia in rat brain studies, and even allows for the simultaneous study of behavior along with neurochemistry by PET. We have also developed new approaches for very high spatial resolution in PET, including a solid-state imager using cadmium zinc telluride (CZT) which achieves sub-mm resolution, and a monolithic scintillator detector with depth-encoding capability via a novel maximum likelihood positioning algorithm. And we have developed multiple imaging systems for simultaneous imaging with PET and high-field MRI, including a whole plant imaging system. The research encompasses the development of new detector materials and concepts, low-noise microelectronic signal processing, high-throughput data acquisition methods, Monte Carlo simulation, and new data processing techniques to optimize the extraction of quantitative information from the PET data.

See Also: PET Research

Selected Publications

• Vaska P, and Cao T.
  The State of Instrumentation for Combined Positron Emission Tomography and Magnetic Resonance Imaging.
  Seminars in Nuclear Medicine, 43(1):11-18 (2013).
• Maramraju S.H, Smith S.D., Rescia S., Stoll S., Budassi M., Vaska P., Woody C., and Schlyer D.
  Electromagnetic Interactions in a Shielded PET/MRI System for Simultaneous PET/MR Imaging in 9.4 T: Evaluation and Results.
  IEEE Trans Nucl Sci, 59(5):1892-1899 (2012).
• Alexoff D.L., Dewey S.L., Vaska P., Krishnamoorthy S., Ferrieri R., Schueller M., Schlyer D.J., and Fowler J.S.
  PET imaging of thin objects: measuring the effects of positron range and partial-volume averaging in the leaf of Nicotiana tabacum.
  Nucl. Med. Biol., 38(2):191-200. Epub 2010 Oct 27. (Feb 2011).  PubMed
• Maramraju S.H., Smith S.D., Junnarkar S.S., Schulz D., Stoll S., Ravindranath B., Purschke M.L., Rescia S., Southekal S., Pratte J.F., Vaska P., Woody C.L., andSchlyer D.J.
  Small animal simultaneous PET/MRI: initial experiences in a 9.4 T microMRI.
  Physics in Medicine and Biology, 56(8):2459-2480 (2011).  PubMed
• Schulz D., Southekal S., Junnarkar S.S., Pratte J.-F., Purschke M.L., Stoll S.P., Ravindranath B., Maramraju S.H., Krishnamoorthy S., Henn F.A., O'Connor P., Woody C.L., Schlyer D.J., and Vaska P.
  Simultaneous assessment of rodent behavior and neurochemistry using a miniature positron emission tomograph.
  Nat. Meth.,8(4): 347-352 (2011).  PubMed
• Schulz D., and Vaska P.
  The emerging discipline of behavioral neuroimaging.
  Reviews in the Neurosciences, 22(6):591-592 (2011).  PubMed
• Southekal S., Purschke M.L., Schlyer D.J., and Vaska P.
  Quantitative PET Imaging Using a Comprehensive Monte Carlo System Model.
  IEEE Transactions on Nuclear Science, 58(5):2286-2295 (2011).
• Volkow N.D., Tomasi D., Wang G.-J., Vaska P., Fowler J.S., Telang F., Alexoff D., Logan J., and Wong C.
  Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Metabolism.
  Journal of the American Medical Association, 305(8):808-813, (2011).  PubMed
• Junnarkar S.S., O’Connor P., Vaska P., and Fontaine R.
  FPGA-based self-calibrating Time-to-Digital Converter for Time-of-Flight Experiments.
  IEEE Trans. Nucl. Sci., 56(4):2374-2379 (2009).
• Pratte J.F., Junnarkar S., Deptuch G., Fried J., O'Connor P., Radeka V., Vaska P., Woody C., Schlyer D., Stoll S., Maramraju S.H., Krishnamoorthy S., Lecomte R., and Fontaine R.
  The RatCAP Front-End ASIC.
  IEEE Trans. Nucl. Sci., 55(5): 2727-2735 (2008).
• Woody C., Vaska P., Schlyer D., Pratte J.F., Junnarkar S., Park S.J., Stoll S., Purschke M., Southekal S., Kriplani A., Krishnamoorthy S., Maramraju S., Lee D., Schiffer W., Dewey S., Neill J., Kandasamy A., O'Connor P., Radeka V., Fontaine R. and Lecomte R.
  Initial studies using the RatCAP conscious animal PET tomograph.
  Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 571(1-2):14-17 (2007).
• Vaska P., Rubins D.L., Alexoff D. and Schiffer W.
  Quantitative Imaging with the microPET Small-Animal PET Tomograph.
  Int Rev Neurobiol., 73:191-218 (2006).  PubMed
• Vaska P., Woody C.L., Schlyer D.J., Shokouhi S., Stoll S.P., Pratte J.-.F, O’Connor P., Junnarkar S.S., Rescia S., Yu B., Purschke M., Kandasamy A., Villanueva A., Kriplani A., Radeka V., Volkow N., Lecomte R. and Fontaine R.
  RatCAP: Miniaturized Head-Mounted PET for Conscious Rodent Brain Imaging.
  IEEE Trans. Nucl. Sci., 51(5):2718-2722 (2004).
• Vaska P., Stoll S.P., Woody C.L., Schlyer D.J. and Shokouhi S.
  Effects of Inter-Crystal Cross-Talk on Multi-Element LSO/APD PET Detectors.
  IEEE Transactions on Nuclear Science, 50(3):362-366 (2003).
• Alexoff D.L., Vaska P., Marsteller D., Gerasimov T., Li J., Logan J., Fowler J.S., Taintor N.B., Thanos P.K. and Volkow, N.D.
  Reproducibility of 11C-Raclopride Binding in the Rat Brain Measured with the MicroPET R4: Effects of Scatter Correction and Tracer Specific Activity.
  Journal of Nuclear Medicine, 44(5):815-822 (2003).  PubMed
• Vaska P., Petrillo M.J. and Muehllehner G.
  Virtual PMTs: Improving Centroid Positioning Performance near the Edges of a Gamma Camera Detector.
  IEEE Transactions on Nuclear Science, 48:645-649 (2001).
• Vaska P., Fossan D.B., LaFosse D.R., Schnare H., Waring M.P., Mullins S.M., Hackman G., Prevost D., Waddington J.C., Janzen V.P., Ward D., Wadsworth R. and Paul E.S.
  Particle-hole induced electric and magnetic rotation in 111In.
  Physical Review, 57:1634 (1998).
• Vaska P., Beausang C.W., Fossan D.B., Hughes J.R., Ma R., Paul E.S., Poynter R.J., Regan P.H., Wadsworth R., Forbes S.A., Mullins S.M. and Nolan P.J.
  High-spin structure of 139Eu.
  Phys Rev C Nucl Phys., 52(3):1270-1277 (1995).  PubMed
• Vaska P., Bhattacharjee S., Fossan D.B., LaFosse D.R., Liang Y., Schnare H., Starosta K., Waring M.P., Hibbert I., Wadsworth R., Hauschild K., Beausang C.W., Clarke S., Forbes S.A., Nolan P.J., Paul E.S., Semple A.T., Mullins S.M., Grawe H. and Maier K.H.
  Neutron i13/2 intruder band in 139Sm.
  Phys Rev C Nucl Phys., 50(1):104-109 (1994).  PubMed