1. 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

2. 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

3. First Paper (May 2007)

4. Independent Work (Oct. 2007)

5. Interior CT Patent

6. Literature Analysis

7. Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More

8. Less Is Deeper Use of less projection data for accurate image reconstruction demands deeper insight, more advanced theory and more powerful tools.

9. y t  x Computed Tomography (Wholesale) Measurement Projection:Linear integrals  Sinogram p Object t X-rays Reconstruction

10. Inner Vision with Local Data (Retail) y t x Measurement Projection:Linear integrals Sinogram X X Object t X-rays Reconstruction

11. Earliest BPF Formula (1991)

13. Half-PI-Line Reconstruction (2006) Field of View (FOV) Partial-PI-Line

14. Extrapolation from a Known Point (2006) FOV ?

15. Curved Filtering Path (2003) ?

16. (HU) (HU) (c) (d) (Pixel) (Pixel) Interior Reconstruction Global FBP Local FBP Local SART Interior Recon (a) (b)

17. HOT

18. Sparsity-based Interior Recon

19. Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More

20. 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.

21. X-ray Beam Central Stop Rotation Axis Sample Phase Ring Zone Plate Detector Plane Condense Lens ROI Sample Stage Preclinical Nano-CT

22. Potential for Study on Earliest Life Hagadorn JW, et al. (2006) Cellular and subcellular structure of Neoproterozoic embryos. Science 314:291–294

23. Big Patient Problem

24. Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More

25. 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.

26. Spiral Cone-beam CT

27. Dual-source Clinical CT (2005)

28. 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

29. From Scanning to Roaming

30. Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More

31. 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.

32. Reduced Angular Sampling Rate Need 4 Projections Need 2 Projections

33. 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

34. Outline • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More

35. 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!

36. Interior-MRI ……………………………………

37. 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

38. Interior Electron Tomography Ge Wang, HengyongYu

39. Limited Angle Interior Tomography

40. Interior SPECT

41. 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

42. Practical Implications

43. Conclusion • Less Is Deeper • Less Is Larger • Less Is Faster • Less Is Less • Less Is More

44. Less Is Not Always Better

45. Link of Localities Pictures from http://www.bing.com

46. Future Work • Multi-scale Interior Tomography • Multi-parameter Interior Tomography • Multi-energy Interior Tomography

47. SBES Advanced Multi-scale CT Facility

48. Smaller Scales?

49. Larger Scales?

50. Multi-parameter CT