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CT and IGCT

CT and IGCT. Norbert J. Pelc, Sc.D. Department of Radiology Stanford University. Outline. We get the best toys opportunities in MDCT And we make some toys too Inverse Geometry CT (IGCT). CT Input/Output. distribution of m. array of. CT. projection. Reconstruction. data. Program.

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CT and IGCT

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  1. CT and IGCT Norbert J. Pelc, Sc.D. Department of Radiology Stanford University

  2. Outline • We get the best toys • opportunities in MDCT • And we make some toys too • Inverse Geometry CT (IGCT)

  3. CT Input/Output distributionof m array of CT projection Reconstruction data Program

  4. Filtered-backprojection

  5. * source source * detector detector Volumetric coverage Helical CT requires multiple rotations Multi-slice helical requires fewer rotations

  6. Where will it end?

  7. The Continuing Evolution: MDCT

  8. CT future directions • Cheaper • lower cost multi-row detectors and electronics • lower cost computer systems • Faster • scan times < 100 ms • Better

  9. Multi-source systems reduced minimum gantry rotation significant increase in scan speed and cost could have major application impact Berninger et al, US Patent 4,196,352, filed 1978

  10. CT future directions • Cheaper • lower cost multi-row detectors and electronics • lower cost computer systems • Faster • scan times < 100 ms • faster volumetric coverage • “an organ in a rotation” • Better

  11. CT future directions • Cheaper • lower cost multi-row detectors and electronics • lower cost computer systems • Faster • scan times < 100 ms • faster volumetric coverage • “an organ in a rotation” • Better • better contrast discrimination • higher spatial resolution • lower dose

  12. CT future directions • Cheaper • lower cost multi-row detectors and electronics • lower cost computer systems • Faster • scan times < 100 ms • faster volumetric coverage • “an organ in a rotation” • Better • better contrast discrimination • higher spatial resolution • lower dose

  13. * source detector source * detector Volumetric CT approaches Multi-row helical requires multiple rotations Cone beam VCT Scan the volume in a single rotation, or step-and-shoot

  14. VCT with flat panel detectors • Siemens Axiom Artis • GE CR&D

  15. Cone beam artifacts Cone beam VCT system, stack of 9 disks 9 cone angle (10 cm z-FOV @ 65 cm), Feldkamp reconstruction K. Sourbelle, et al, , RSNA 2003, #183

  16. Cone beam artifacts

  17. Cone beam artifacts indistingushable objects fundamental problem, no correction exists

  18. NexRay, Inc., Los Gatos, CA Inverse-Geometry CT (IGCT) system designs reconstruction methods simulations and experiments detector array detector array 2D scanned anode x-ray source source and detector have the same axial extent

  19. Inverse-Geometry VCT Axial Sagittal

  20. “Defrise” phantom Cone-beam VCT IGCT No cone-beam artifacts!

  21. Cadaver inner ear conventional IGCT

  22. Conclusions • MDCT • cheaper, faster, better • better spatial and temporal resolution • lower radiation dose • “Organ in a rotation” with outstanding image quality needs a different approach • Cannot use a simple point x-ray source • Inverse Geometry CT (IGCT) • preliminary results are promising • Hang on to your hat, the data will fly in!

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