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The Meaning of Interior Tomography. Ge Wang, PhD, Director SBES Division & ICTAS Center for Biomedical Imaging VT-WFU School of Biomedical Engineering & Sciences Virginia Tech, Blacksburg, VA, USA ge-wang@ieee.org October 1, 2010. Interior Tomography (2007). Source. Beam. Beam. ROI.
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The Meaning of Interior Tomography • Ge Wang, PhD, Director • SBES Division & ICTAS Center for Biomedical Imaging • VT-WFU School of Biomedical Engineering & Sciences • Virginia Tech, Blacksburg, VA, USA • ge-wang@ieee.org • October 1, 2010
Interior Tomography (2007) Source Beam Beam ROI Object Object Trajectory Trajectory Interior Problem Regular Reconstruction Known Sub-region Sparsity Model Beam Beam ROI ROI Object Object Trajectory Trajectory Landmark-based Interior Tomography Sparsity-based Interior Tomography
Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More
Less Is Deeper Use of less projection data for accurate image reconstruction demands deeper insight, more advanced theory and more powerful tools.
y t x Computed Tomography (Wholesale) Measurement Projection:Linear integrals Sinogram p Object t X-rays Reconstruction
Inner Vision with Local Data (Retail) y t x Measurement Projection:Linear integrals Sinogram X X Object t X-rays Reconstruction
Half-PI-Line Reconstruction (2006) Field of View (FOV) Partial-PI-Line
(HU) (HU) (c) (d) (Pixel) (Pixel) Interior Reconstruction Global FBP Local FBP Local SART Interior Recon (a) (b)
Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More
Less Is Larger Acquisition of less projection data is achieved with a narrower beam, and an object larger than the beam width is not a concern.
X-ray Beam Central Stop Rotation Axis Sample Phase Ring Zone Plate Detector Plane Condense Lens ROI Sample Stage Preclinical Nano-CT
Potential for Study on Earliest Life Hagadorn JW, et al. (2006) Cellular and subcellular structure of Neoproterozoic embryos. Science 314:291–294
Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More
Less Is Faster Less data means smaller detector size, faster frame rate, and more imaging chains, all of which contribute to accelerate the data acquisition process.
Multi-source Interior Tomography X-ray Detectors ROI X-ray Tubes Wang G, Yu H, Ye YB. Virginia Tech Patent Disclosure on May 15, 2007, US Patent Application 12/362,979 allowed on October 21, 2009 Ye YB, Yu HY, Wei YC, Wang G. International Journal of Biomedical Imaging, Article ID:63634, 2007 Wang G, Yu H, Ye Y. Medical Physics. 36:3575-3581, 2009
Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More
Less Is Less Less data is equivalent to less radiation dose, because of not only a narrower beam but also a more relaxed angular sampling requirement in the longitudinal studies or multi-scale scenarios.
Reduced Angular Sampling Rate Need 4 Projections Need 2 Projections
Statistical Interior Tomography ITHT ML 200,000 photons Work in progress from Qiong Xu & Xuanqin Mou (China) in collaboration with Wang G & Yu HY 50,000 photons
Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More
Less Is More Use of less data is advantageous in more modalities beyond CT, such as other straight-ray tomographic techniques and even in small-angle curvilinear geometry, and more applications of various types. Furthermore, less data means more computational time!
Interior-MRI ……………………………………
Interior-MRI Traditional MRI Interior MRI Zhang J, Yu HY, Corum C, Garwood M, Wang G: Exact and stable interior ROI reconstruction for radial MRI. SPIE 7258: 2585G, 8 pages, Feb. 2009, Orlando, FL, USA
Interior Electron Tomography Ge Wang, HengyongYu
Interior-SPECT µa=0.3cm-1 µa=0cm-1 µa=0.15cm-1 FOV Ideal data Known Support Noisy data Yu HY, Yang JS, Jiang M, Wang G: Interior SPECT- Exact and stable ROI reconstruction from uniformly attenuated local projections; Communications in Numerical Methods in Engineering, 25(6):693-710, 2009
Conclusion • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More
Link of Localities Pictures from http://www.bing.com
Future Work • Multi-scale Interior Tomography • Multi-parameter Interior Tomography • Multi-energy Interior Tomography