Calculation of single detector efficiencies and extension of the normalization sinogram in PET

Flemming Hermansen, Terry J. Spinks, Paolo G. Camici, Adriaan A. Lammertsma

Research output: Contribution to journalArticle

Abstract

A fast iterative method is presented for calculating single detector efficiencies for positron emission tomographs. These efficiencies can be used to extend the normalization scan to areas outside that covered by the normalization source. The root mean square (rms) error of the calculated single detector efficiencies decreases exponentially with the number of iterations. Thirty iterations per normalization image are sufficient and take about 1 s on a SUN Classic. The geometry factors are composed of factors which only depend on the distance from the centre of the held-of-view (FOV) and of factors which show a more complex pattern over the normalization sinogram. The geometry factors are specific to each scanner. On the ECAT 931 scanner the complex part of the geometry factors showed a diamond shaped pattern (caused by the varying sensitivity of single detectors in a detector block with varying angle of incidence) and S-shaped curves (representing attenuation caused by supporting rods for the ring source). The coefficient of variation of the diamond-shaped pattern was 4% for detectors farthest from the centre of the FOV. Extensions of the normalization scan may, therefore, contain a relative rms error of about 4% if the applied geometry factors only take the distance from the centre of the FOV into account.

Original languageEnglish
Pages (from-to)1143-1154
Number of pages12
JournalPhysics in Medicine and Biology
Volume42
Issue number6
DOIs
Publication statusPublished - Jun 1997

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Diamond
Detectors
detectors
Geometry
root-mean-square errors
Mean square error
Electrons
geometry
Diamonds
scanners
iteration
Incidence
diamonds
Positrons
Iterative methods
positrons
rods
incidence
attenuation
sensitivity

ASJC Scopus subject areas

  • Biomedical Engineering
  • Physics and Astronomy (miscellaneous)
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this

Calculation of single detector efficiencies and extension of the normalization sinogram in PET. / Hermansen, Flemming; Spinks, Terry J.; Camici, Paolo G.; Lammertsma, Adriaan A.

In: Physics in Medicine and Biology, Vol. 42, No. 6, 06.1997, p. 1143-1154.

Research output: Contribution to journalArticle

Hermansen, Flemming ; Spinks, Terry J. ; Camici, Paolo G. ; Lammertsma, Adriaan A. / Calculation of single detector efficiencies and extension of the normalization sinogram in PET. In: Physics in Medicine and Biology. 1997 ; Vol. 42, No. 6. pp. 1143-1154.
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