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Application of blind deblurring reconstruction technique to SPECT imaging.

Li H, Zheng Y - Int J Biomed Imaging (2007)

Bottom Line: The algorithm imposes certain spatial-frequency domain constraints on the reconstruction volume and the PSF and does not otherwise assume knowledge of the PSF.The algorithm alternates between two iterative update sequences that correspond to the PSF and radioactivity estimations, respectively.In experimental studies, the contrast and quality of reconstruction was substantially improved with the blind deblurring reconstruction algorithm.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Physics, MD Anderson Cancer Center, University of Texas, Houston, TX 77030, USA.

ABSTRACT
An SPECT image can be approximated as the convolution of the ground truth spatial radioactivity with the system point spread function (PSF). The PSF of an SPECT system is determined by the combined effect of several factors, including the gamma camera PSF, scattering, attenuation, and collimator response. It is hard to determine the SPECT system PSF analytically, although it may be measured experimentally. We formulated a blind deblurring reconstruction algorithm to estimate both the spatial radioactivity distribution and the system PSF from the set of blurred projection images. The algorithm imposes certain spatial-frequency domain constraints on the reconstruction volume and the PSF and does not otherwise assume knowledge of the PSF. The algorithm alternates between two iterative update sequences that correspond to the PSF and radioactivity estimations, respectively. In simulations and a small-animal study, the algorithm reduced image blurring and preserved the edges without introducing extra artifacts. The localized measurement shows that the reconstruction efficiency of SPECT images improved more than 50% compared to conventional expectation maximization (EM) reconstruction. In experimental studies, the contrast and quality of reconstruction was substantially improved with the blind deblurring reconstruction algorithm.

No MeSH data available.


Related in: MedlinePlus

One slice of a mouse-heart reconstruction.
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fig7: One slice of a mouse-heart reconstruction.

Mentions: We also used the blind deblurringreconstruction technique in a study of cardiac inflammation (i.e., a heartattack) in a mouse resulting from ischemia caused by injection of Tc 99m-labeled antibody.How the antibody accumulated in the heart was of great interest. Approximately900 Ci of Tc 99m-labeled antibodywas injected into a mouse. The mouse was euthanized 6 hours after theinjection, and the heart, which had a diameter of less than 1 cm, was removedand scanned on a CT/SPECT dual-modality scanner. CT projection data wereacquired at 1 second per frame for a total scan time of 6 minutes, and SPECTprojection data were acquired at 60 seconds per frame for a total scan time ofapproximately 1 hour. Figure 7 shows a reconstruction slice from the SPECTreconstruction and a fused slice of CT and SPECT reconstruction. No attenuationcorrection was made in the reconstruction process for this study.


Application of blind deblurring reconstruction technique to SPECT imaging.

Li H, Zheng Y - Int J Biomed Imaging (2007)

One slice of a mouse-heart reconstruction.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2233986&req=5

fig7: One slice of a mouse-heart reconstruction.
Mentions: We also used the blind deblurringreconstruction technique in a study of cardiac inflammation (i.e., a heartattack) in a mouse resulting from ischemia caused by injection of Tc 99m-labeled antibody.How the antibody accumulated in the heart was of great interest. Approximately900 Ci of Tc 99m-labeled antibodywas injected into a mouse. The mouse was euthanized 6 hours after theinjection, and the heart, which had a diameter of less than 1 cm, was removedand scanned on a CT/SPECT dual-modality scanner. CT projection data wereacquired at 1 second per frame for a total scan time of 6 minutes, and SPECTprojection data were acquired at 60 seconds per frame for a total scan time ofapproximately 1 hour. Figure 7 shows a reconstruction slice from the SPECTreconstruction and a fused slice of CT and SPECT reconstruction. No attenuationcorrection was made in the reconstruction process for this study.

Bottom Line: The algorithm imposes certain spatial-frequency domain constraints on the reconstruction volume and the PSF and does not otherwise assume knowledge of the PSF.The algorithm alternates between two iterative update sequences that correspond to the PSF and radioactivity estimations, respectively.In experimental studies, the contrast and quality of reconstruction was substantially improved with the blind deblurring reconstruction algorithm.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Physics, MD Anderson Cancer Center, University of Texas, Houston, TX 77030, USA.

ABSTRACT
An SPECT image can be approximated as the convolution of the ground truth spatial radioactivity with the system point spread function (PSF). The PSF of an SPECT system is determined by the combined effect of several factors, including the gamma camera PSF, scattering, attenuation, and collimator response. It is hard to determine the SPECT system PSF analytically, although it may be measured experimentally. We formulated a blind deblurring reconstruction algorithm to estimate both the spatial radioactivity distribution and the system PSF from the set of blurred projection images. The algorithm imposes certain spatial-frequency domain constraints on the reconstruction volume and the PSF and does not otherwise assume knowledge of the PSF. The algorithm alternates between two iterative update sequences that correspond to the PSF and radioactivity estimations, respectively. In simulations and a small-animal study, the algorithm reduced image blurring and preserved the edges without introducing extra artifacts. The localized measurement shows that the reconstruction efficiency of SPECT images improved more than 50% compared to conventional expectation maximization (EM) reconstruction. In experimental studies, the contrast and quality of reconstruction was substantially improved with the blind deblurring reconstruction algorithm.

No MeSH data available.


Related in: MedlinePlus