European Journal of Nuclear Medicine

, Volume 13, Issue 9, pp 439–442

Artifacts in camera based single photon emission tomography due to time activity variation

  • B. D. Bok
  • A. N. Bice
  • M. Clausen
  • D. F. Wong
  • H. N. WagnerJr
Article

DOI: 10.1007/BF00281856

Cite this article as:
Bok, B.D., Bice, A.N., Clausen, M. et al. Eur J Nucl Med (1987) 13: 439. doi:10.1007/BF00281856
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Abstract

Image quality in single photon emission computed tomography (SPECT) using a rotating gamma camera is dependent on the time course of the tracer in the field of view. If acquisition times are slow comapred to the tracer turnover, artifacts may occur in the reconstructed images. The properties of such artifacts were studied by computer simulation. Experimental projection data of point sources, cylindrical phantoms, and an anatomically realistic brain phantom were altered by sequentially weighting the projections with a function that varied exponentially or linearly with time. The observed distortion in the reconstructed images could be related to the ratio between the object activity variation and the camera rotation time. If the tracer concentration changed less than a factor of two during one camera rotation then little image distortion was visible although quantitatively the resolution was degraded.

If the object's activity variation with time is fast enough to produce noticeable distortion, the artifacts can be reduced by performing multiple, rapid, camera rotations, instead of one rotation, for the same total acquisition time. The proposed procedure is computer storage space intensive and takes longer to produce the transaxial images, but improves image quality.

Key words

Emission tomography Image distortion Gamma camera 

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • B. D. Bok
    • 1
  • A. N. Bice
    • 2
  • M. Clausen
    • 3
  • D. F. Wong
    • 2
  • H. N. WagnerJr
    • 2
  1. 1.Service de Médecine Nucléaire et BiophysiqueHôpital BeaujonClichyFrance
  2. 2.Division of Nuclear Medicine and Radiation Health SciencesThe Johns Hopkins Medical InstitutionsBaltimoreUSA
  3. 3.Department of Nuclear MedicineAK St. GeorgHamburgFederal Republic of Germany
  4. 4.Hôpital BeaujonClichyFrance

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