Dr. Rolf Clackdoyle

The Ottawa Hospital - Diagnostic Imaging - RECON
Civic Campus
1053 Carling Avenue, Room S50
(613) 798 5555 x12035
rolf [dot] clackdoyleatuniv-grenoble-alpes [dot] fr

Research Summary

Analytic methods image reconstruction from projections: Development of theory and algorithms for limited data problems in classical tomography, for example, region-of-interest reconstruction from truncated projections. Analysis of sufficient and insufficient data configurations and what object features can and can not be reliably reconstructed in these situations.

Dynamic region-of-interest reconstruction: Development of theory and reconstruction algorithms for imaging non-static specimens with incomplete (e.g. truncated) data. A typical example would be scanning a patient throughout several respiratory cycles with a detector too small to cover the full transaxial extent. 

Geometric calibration of cone-beam scanners: Development of direct analytic methods of obtaining geometric parameters of a generic cone-beam scanner by imaging a known calibration phantom and extracting the scanner geometry from the measurements using direct formulas.

Data consistency conditions in tomography: Theory and applications of data consistency conditions for scanners using divergent beam projections. For example, x-ray imaging systems or pinhole SPECT systems use fan-beam or cone-beam projections which are 2D and 3D divergent beam projections.


Selected Publications:


  1. R. Clackdoyle. 2018. "Data consistency for linograms and planograms." IEEE Trans. Radiation and Plasma Med. Sci (accepted March 2018).
  2. J. Lesaint, S. Rit, R. Clackdoyle, L. Desbat. 2017. "Calibration for circular cone-beam CT based on consistency conditions." IEEE Trans. Radiation and Plasma Med. Sci. 1, 517-526.
  3. T. Sun, R. Clackdoyle, J.-H. Kim, R. Fulton, J. Nuyts. 2017. "Estimation of local data-insufficiency in motion-corrected helical CT." IEEE Trans. Radiation and Plasma Med. Sci. 1, 346-357.
  4. R. Clackdoyle, F. Noo, F. Momey, L. Desbat. 2017. "Accurate transaxial region-of-interest reconstruction in helical CT?" IEEE Trans. Radiation and Plasma Med. Sci. 1, 334-345.
  5. R. Clackdoyle, L. Desbat, J. Lesaint, S. Rit. 2016. "Data consistency conditions for cone-beam projections on a circular trajectory." IEEE Sig. Proc. Let. 23, 1746-1750.
  6. S. Rit, R. Clackdoyle, P. Keuschnigg, P. Steininger. 2016. "Filtered backprojection reconstruction for a cone-beam computed tomography scanner with independent source and detector rotations." Med. Phys. 43, 2344-2352.
  7. J. Hoskovec, R. Clackdoyle, L. Desbat, S. Rit. 2016. "Exact fan-beam reconstruction with arbitrary patient translations and truncated projections." IEEE Trans. Nucl. Sci. 63, 1408-1418.
  8. R. Clackdoyle, L. Desbat. 2015. "Data consistency conditions for truncated fanbeam and parallel projections." Med. Phys. 42, 831- 845.
  9. R. Clackdoyle, L. Desbat. 2013. "Full data consistency conditions for conebeam projections with sources on a plane." Phys. Med. Biol. 58, 8437-8456.
  10. R. Clackdoyle. 2013. "Necessary and sufficient consistency conditions for fanbeam projections along a line" IEEE Trans. Nucl. Sci. 60, 1560-1569
  11. R.Clackdoyle, C.Mennessier. 2011. "Centers and centroids of the conebeam projection of a ball." Phys. Med. Biol. 56, 7371-7391
  12. R.Clackdoyle, M.Defrise. 2010. "Tomographic Reconstruction in the 21st Century. Region-of-interest reconstruction from incomplete data." IEEE Signal Processing. 27(4), 60-80
  13. C.Mennessier, R.Clackdoyle, F.Noo. 2009. "Direct determination of geometric parameters for cone-beam scanners," Phys. Med. Biol. 54, 1633-1660.
  14. S.Bartolac, R.Clackdoyle, F.Noo, J.Siewerdsen, D.Moseley, D.Jaffray. 2009. "A local shift-variant Fourier model and experimental validation of circular cone-beam tomography artifacts," Med. Phys. 36, 500-512