Medical Imaging
Computed Tomography (CT)
Image Reconstruction
Inverse problems
X-ray Measurements
Data Acquisition and Calibration
Signal Processing
Measurement Device Simulations
Scientific Reports and Publications
Project Strategy and Proposals
Image Quality Metrics
Feature Identification
Image Processing
Non-Destructive Testing
Machine Vision
  The Team

David Rohler, Ph.D.

David Rohler has over 30 years of experience with imaging development for medical devices and instrumentation products. Combining a strong theoretical background with a well-developed instrumentation capability, he has led efforts to design state-of-art medical imaging devices and managed key product development efforts. Since he founded Plexar Associates, Inc. in 1987, David has guided Plexar’s involvement with a wide range of clients and projects, providing high-level consulting services for the medical and industrial imaging communities. He is co-inventor on 12 patents and co-author on 6 papers and presentations. David received his Ph.D. from Case Western Reserve University in 1983. His professional affiliations include SIAM and RSNA.


Steven H. Izen, Ph.D.

Steven Izen has been a key contributor for Plexar projects since 1999. He is a Professor of Mathematics at Case Western Reserve University teaching classes on the Mathematics of Image Reconstruction and Engineering Mathematics. Steve develops and implements reconstruction algorithms for tomographic imaging and other inverse problems arising in medical and industrial settings. He also has experience in optical modeling. His current interests include sampling issues in three-dimensional tomography and the analysis and development of cone-beam CT reconstruction algorithms. Dr. Izen has been the PI on two NASA grants, an Ameritech Foundation grant, and a co-PI on two NSF equipment grants. He has 10 peer-reviewed publications. He received his Ph.D. from Massachusetts Institute of Technology in 1983.


Thomas L. Toth

Tom Toth was a key scientist and engineer at GE Healthcare for over 20 years, with an emphasis on new product development, new technology feasibility and clinical research with a focus on medical physics and CT dose reduction. While at GE, Tom authored 79 issued patents, 19 peer-reviewed publications and 8 presentations at RSNA and AAPM. Tom is active in a variety of national and international medical imaging groups including: (1) AAPM where he is an active member of the task group focused on "The Future of CT Dosimetry," (2) International Society for Optical Engineering, Physics of Medical Imaging, (3) NEMA, Medical Imaging and Technology Alliance (MITA) where he is chairman of the CT physics work group, (4) International Electro Technical Commission - CT Maintenance Group, (5) Alliance for Radiation Safety in Pediatric Imaging, where Tom is co-chair of the Pediatric CT Physics Work Group.


Arjun K. Maniyedath, M.S.

Arjun K. Maniyedath combines biomedical applications experience with a strong background in software and hardware engineering. He has hands-on experience with many facets of the x-ray equipment business including installation, testing, maintenance, user training and service training. Using IDL and C++, Arjun has developed key software systems and algorithms for various imaging applications including CT data acquisition, CT calibration and reconstruction, vision system inspections and image quality analysis. He received his M.S. degree from the University of Akron.



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