Skip to main content
SpringerLink
Log in

Use of scanner characteristics in iterative image reconstruction for high-resolution positron emission tomography studies of small animals

  • Original Article
  • Published:
European Journal of Nuclear Medicine Aims and scope Submit manuscript

Abstract

The purpose of this work was to improve of the spatial resolution of a whole-body positron emission tomography (PET) system for experimental studies of small animals by incorporation of scanner characteristics into the process of iterative image reconstruction. The image-forming characteristics of the PET camera were characterized by a spatially variant line-spread function (LSF), which was determined from 49 activated copper-64 line sources positioned over a field of view (FOV) of 21.0 cm. This information was used to model the image degradation process. During the course of iterative image reconstruction, the forward projection of the estimated image was blurred with the LSF at each iteration step before the estimated projections were compared with the measured projections. The imaging characteristics of the high-resolution algorithm were investigated in phantom experiments. Moreover, imaging studies of a rat and two nude mice were performed to evaluate the imaging properties of our approach in vivo. The spatial resolution of the scanner perpendicular to the direction of projection could be approximated by a one-dimensional Gaussian-shaped LSF with a full-width at half-maximum increasing from 6.5 mm at the centre to 6.7 mm at a radial distance of 10.5 cm. The incorporation of this blurring kernel into the iteration formula resulted in a significantly improved spatial resolution of about 3.9 mm over the examined FOV As demonstrated by the phantom and the animal experiments, the high-resolution algorithm not only led to a better contrast resolution in the reconstructed emission scans but also improved the accuracy for quantitating activity concentrations in small tissue structures without leading to an amplification of image noise or image mottle. The presented data-handling strategy incorporates the image restoration step directly into the process of algebraic image reconstruction and obviates the need for ill-conditioned ”deconvolution“ procedures to be performed on the projections or on the reconstructed image. In our experience, the proposed algorithm is of special interest in experimental studies of small animals.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Hoffman EJ, Huang SC, Phelps ME. Quantitation in positron emission computed tomography. I. Effect of object size.J Comput Assist Tomogr 1979; 3: 299–308.

    PubMed  Google Scholar 

  2. Brix G, Zaers J, Adam LE, et al. Performance evaluation of a whole-body PET scanner using the NEMA protocol.J Nucl Med 1997; in press.

  3. Derenzo SE, Huesman RH, Cahoon JL, et al. A positron tomograph with 600 BGO crystals and 2.6 mm resolution.IEEE Trans Nucl Sci 1988; 35: 659–664.

    Google Scholar 

  4. Spinks TJ, Jones T, Bailey DL, et al. Physical performance of a positron tomograph for brain imaging with retractable septa.Phys Med Biol 1992; 37: 1637–1655.

    PubMed  Google Scholar 

  5. Freifelder R, Karp JS, Geagan M, Muehllehner G. Design and performance of the HEAD PENN-PET scanner.IEEE Trans Nucl Sci 1994; 41:1436–1440.

    Google Scholar 

  6. Tavernier S, Bruyndonckx P, Shuping Z. A fully 3D small PET scanner.Phys Med Biol 1992; 37: 635–643.

    PubMed  Google Scholar 

  7. Cutler PD, Cherry SR, Hoffman EJ, Digby WM, Phelps ME. Design features and performance of a PET system for animal research.J Nucl Med 1992; 33: 595–604.

    PubMed  Google Scholar 

  8. Marriott CJ, Cadorette JE, Lecomte R, Scasnar V, Rousseau J, van Lier JE. High-resolution PET imaging and quantitation of pharmaceutical biodistribution in a small animal using avalanche photodiode detectors.J Nucl Med 1994; 35: 1390–1397.

    PubMed  Google Scholar 

  9. Magata Y, Saji H, Choi SR, et al. Noninvasive measurement of cerebral blood flow and glucose metabolic rate in the rat with high-resolution animal positron emission tomography (PET): a novel in vivo approach for assessing drug action in the brain of small animals.Biol Pharm Bull 1995; 18: 753–756.

    PubMed  Google Scholar 

  10. Bloomfield PM, Rajeswaran S, Spinks TJ, et al. The design and physical characteristics of a small animal positron emission tomograph.Phys Med Biol 1995; 40: 1105–1126.

    PubMed  Google Scholar 

  11. Andrews HC, Hunt BR. Digital image restoration. Englewood Cliffs, New Jersey: Prentice-Hall, 1977.

    Google Scholar 

  12. Webb S. The mathematics of image formation and image processing. In: Webb S, ed.The physics of medical imaging. Bristol and Philadelphia: Institute of Physics Publishing; 1988:534–566.

    Google Scholar 

  13. Pratt WK. Digital image processing, 2nd edn. New York: Wiley; 1991: 323–419.

    Google Scholar 

  14. Webb S, Long AP, Ott RJ, Leach MO, Flower MA. Constrained deconvolution of SPELT liver tomograms by direct digital image restoration.Med Phys 1985; 12: 53–58.

    PubMed  Google Scholar 

  15. Webb S. Comparison of data-processing techniques for the improvement of contrast in SPET liver tomograms.Phys Med Biol 1985; 30: 1077–1086.

    PubMed  Google Scholar 

  16. Derenzo SE. Mathematical removal of positron range blurring in high resolution tomography.IEEE Trans Nucl Sci 1986; 33: 565–569.

    Google Scholar 

  17. Huesman RH, Salmeron EM, Baker JR. Compensation for crystal penetration in high resolution positron tomography.IEEE Trans Nucl Sci 1989; 36: 1084–1089.

    Google Scholar 

  18. Liang Z. Detector response restoration in image reconstruction of high resolution positron emission tomography.IEEE Trans Med Imaging 1994; 13: 314–321.

    Google Scholar 

  19. Luig H, Eschner W, Bähre M, Voth E, Nolte G. Eine iterative Strategie zur Bestimmung der Quellverteilung bei der Einzelphotonen-Tomographie mit einer rotierenden Gammakamera (SPELT).Nuklearmedizin 1988; 27: 140–146.

    PubMed  Google Scholar 

  20. Shepp LA, Vardi Y. Maximum likelihood reconstruction for emission tomography.IEEE Trans Med Imaging 1982; 1: 113–122.

    Google Scholar 

  21. Vardi Y, Shepp LA, Kaufman L. A statistical model for positron emission tomography.J Am Stat Assoc 1985; 80: 8–20.

    Google Scholar 

  22. Lewitt RM, Muehllehner G. Accelerated iterative reconstruction for positron emission tomography based on the EM algorithm for maximum likelihood estimation.IEEE Trans Med Imaging 1986, 5: 16–22.

    Google Scholar 

  23. Zeng GL, Gullberg GT. Valid backprojection matrices which are not the transpose of the projection matrix [abstract].J Nucl Med 1996; 37: 206P.

    Google Scholar 

  24. Kamphuis C, Beekman FJ, Viergever MA, van Rijk PP. Accelerated fully 3D SPELT reconstruction using dual matrix ordered subsets [abstract].J Nucl Med 1996; 37: 62P.

    Google Scholar 

  25. Ostertag H, Kübler WK, Doll J, Lorenz WJ. Measured attenuation correction methods.Eur J Nucl Med 1989; 15: 722–726.

    PubMed  Google Scholar 

  26. Bergström M, Eriksson L, Bohm C, Blomqvist G, Litton J. Correction for scattered radiation in a ring detector positron camera by integral transformation of the projections.J Comput Assist Tomogr 1983; 7: 42–50.

    PubMed  Google Scholar 

  27. Hoverath H, Kübler WK, Ostertag HJ, et al. Scatter correction in the transaxial slices of a whole-body positron emission tomograph.Phys Med Biol 1993; 38: 717–728.

    Google Scholar 

  28. Schuhmacher J, Klivényi G, Matys R, et al. Multistep tumor targeting in nude mice using bispecific antibodies and a gallium chelate suitable for immunoscintigraphy with positron emission tomography.Cancer Res 1995; 55: 115–123.

    PubMed  Google Scholar 

  29. Watson CC, Newport D, Casey ME. A single scatter simulation technique for scatter correction in 3D PET. In: Grangeat P, Amans JL, eds. Three-dimensional image reconstruction in radiology and nuclear medicine. Dordrecht: Kluwer; 1996: 255–268.

    Google Scholar 

  30. Derenzo SE. Initial characterization of a BGO-silicon photodiode detector for high resolution positron emission tomography.IEEE Trans Nucl Sci 1984; 31: 620–626.

    Google Scholar 

  31. Karp JS, Daube-Witherspoon ME. Determination of depth-ofinteraction in scintillation crystals using a temperature gradient.Nucl Instrum Meth 1987; A260: 509–517.

    Google Scholar 

  32. Derenzo SE, Moses WW, Jackson HG, et al. Initial characterization of a position-sensitive photodiode/BGO detector for PET.IEEE Trans Nucl Sci 1989; 36: 1084–1089.

    Google Scholar 

  33. Yamashita T, Watanabe M, Shimizu K, Uchida H. High resolution block detectors for PET.IEEE Trans Nucl Sci 1990; 37: 589–593.

    Google Scholar 

  34. Bartzakos P, Thompson CJ. A PET detector with depth-of-interaction determination.Phys Med Biol 1991; 36: 735–748.

    Google Scholar 

  35. Rogers JG. A method for correcting the depth-of-interaction blurring in PET cameras.IEEE Trans Med Imaging 1995; 14: 146–150.

    Google Scholar 

  36. Brix G, Bellemann ME, Haberkorn U, Gerlach L, Lorenz WJ. Assessment of the biodistribution and metabolism of 5-fluorouracil as monitored by18F- PET and19F MRI: a comparative animal study.Nucl Med Biol 1996; 23: 897–906.

    PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Research Program “Radiological Diagnostics and Therapy”, German Cancer Research Center (DKFZ), Heidelberg, Germany

    Gunnar Brix, Josef Doll, Matthias E. Bellemann, Herbert Trojan, Uwe Haberkorn, Peter Schmidlin & Hermann Ostertag

Authors
  1. Gunnar Brix
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Josef Doll
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Matthias E. Bellemann
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Herbert Trojan
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Uwe Haberkorn
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Peter Schmidlin
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Hermann Ostertag
    View author publications

    You can also search for this author in PubMed Google Scholar

Additional information

This paper is dedicated to Professor Dr. Walter J. Lorenz, on the occasion of his 65th birthday

Rights and permissions

Reprints and permissions

About this article

Cite this article

Brix, G., Doll, J., Bellemann, M.E. et al. Use of scanner characteristics in iterative image reconstruction for high-resolution positron emission tomography studies of small animals. Eur J Nucl Med 24, 779–786 (1997). https://doi.org/10.1007/BF00879667

Download citation

  • Received:

  • Revised:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00879667

Key words

Search

Navigation