Evaluation of various attenuation corrections in lung SPECT in healthy subjects

Agnetha Gustafsson, L. Jacobsson, A. Johansson, M. Moonen, Ulf Tylen, B. Bake

Research output: Contribution to journalArticle

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Abstract

The effect of increasingly more sophisticated attenuation correction methods on image homogeneity has been studied in seven healthy subjects. The subjects underwent computed tomography (CT), single photon emission computed tomography (SPECT) and transmission computed tomography (TCT) of the thorax region in the supine position. Density maps were obtained from the CT and TCT studies. Attenuation corrections were performed using five different methods: (1) uniform correction using only the body contour; (2) TCT based corrections using the average lung density; (3) TCT based corrections using the pixel density; (4) CT based corrections using average lung density; and (5) CT based corrections using the pixel density. The isolated attenuation effects were assessed on quotient images generated by the division of images obtained using various attenuation correction methods divided by the non-uniform attenuation correction based on CT pixel density (reference method). The homogeneity was calculated as the coefficient of variation of the quotient images (CV att), showing the isolated attenuation effects. Values of CV att were on average 12.8% without attenuation correction, 10.7% with the uniform correction, 8.1% using TCT map using the average lung density value and 4.8% using CT and average lung density corrections. There are considerable inhomogeneities in lung SPECT slices due to the attenuation effect. After attenuation correction the remaining inhomogeneity is considerable and cannot be explained by statistical noise and camera non-uniformity alone.

Original languageEnglish (US)
Pages (from-to)1087-1095
Number of pages9
JournalNuclear Medicine Communications
Volume24
Issue number10
DOIs
StatePublished - Oct 2003
Externally publishedYes

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Keywords

  • Attenuation correction
  • Lung and thorax region
  • SPECT

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

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