Use of the information contents of scattered photons in SPECT by simultaneous reconstruction from multiple energy windows
- Univ. of North Carolina, Chapel Hill, NC (United States)
Conventional wisdom has been that scattered photons contain no useful information and should be removed from the projection data. However, inspection of the scatter response function (SRF) shows that it has a sharply peaked component, indicating that scattered photons do carry some spatial information. In this work we demonstrate that, combined with iterative reconstruction methods and an accurate model of the SRF, this information can be useful in improving SPECT image quality. We have extended a previously described method for estimating the spatially variant SRF, slab derived scatter estimation (SDSE), to lower energy windows. The method was verified by comparison with MC simulated projection data. Noise-free projection data were simulated using SDSE for a 140 keV primary energy window and stored din seven consecutive 7 keV wide energy windows spanning the range 105-154KeV and a conventional 20% wide photopeak window (126-154 keV). First the data from each energy window were reconstructed using iterative reconstruction methods and a projector-backprojector modeling only attenuation and collimator-detector response. In this case the image quality decreases with decreasing energy, with the images from the lowest energy windows having very poor quality. Similarly, images were reconstructed using interative reconstruction methods and a projector-backprojector modeling the SRF in each energy window. While the images form the lower energy windows are still poorer, the image features are clearly recognizable. This indicates that the data from the lower energy window contain useful information which, if properly modeled, can be recovered. Finally, we reconstructed an image simultaneously from all of the 7 keV wide energy windows using iterative reconstruction methods.
- OSTI ID:
- 197899
- Report Number(s):
- CONF-940605-; ISSN 0161-5505; TRN: 95:007029-0022
- Journal Information:
- Journal of Nuclear Medicine, Vol. 35, Issue Suppl.5; Conference: 41. annual meeting of the Society of Nuclear Medicine, Orlando, FL (United States), 5-8 Jun 1994; Other Information: PBD: May 1994
- Country of Publication:
- United States
- Language:
- English
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