Paper
9 March 2017 Attenuation correction in SPECT images using attenuation map estimation with its emission data
Meysam Tavakoli, Maryam Naji, Ali Abdollahi, Faraz Kalantari
Author Affiliations +
Abstract
Photon attenuation during SPECT imaging significantly degrades the diagnostic outcome and the quantitative accuracy of final reconstructed images. It is well known that attenuation correction can be done by using iterative reconstruction methods if we access to attenuation map. Two methods have been used to calculate the attenuation map: transmission-based and transmissionless techniques. In this phantom study, we evaluated the importance of attenuation correction by quantitative evaluation of errors associated with each method. For transmissionless approach, the attenuation map was estimated from the emission data only. An EM algorithm with attenuation model was developed and used for attenuation correction during image reconstruction. Finally, a comparison was done between reconstructed images using our OSEM code and analytical FBP method before and after attenuation correction. The results of measurements showed that: our programs are capable to reconstruct SPECT images and correct the attenuation effects. Moreover, to evaluate reconstructed image quality before and after attenuation correction we applied a novel approach using Image Quality Index. Attenuation correction increases the quality and quantitative accuracy in both methods. This increase is independent of activity in quantity factor and decreases with activity in quality factor. In EM algorithm, it is necessary to use regularization to obtain true distribution of attenuation coefficients.
© (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Meysam Tavakoli, Maryam Naji, Ali Abdollahi, and Faraz Kalantari "Attenuation correction in SPECT images using attenuation map estimation with its emission data", Proc. SPIE 10132, Medical Imaging 2017: Physics of Medical Imaging, 101324Z (9 March 2017); https://doi.org/10.1117/12.2254828
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Cited by 7 scholarly publications.
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KEYWORDS
Signal attenuation

Single photon emission computed tomography

Expectation maximization algorithms

Image quality

Reconstruction algorithms

Tissues

Image restoration

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