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Evaluation of six scatter correction methods based on spectral analysis in (99m)Tc SPECT imaging using SIMIND Monte Carlo simulation.

Asl MN, Sadremomtaz A, Bitarafan-Rajabi A - J Med Phys (2013)

Bottom Line: Except for the dual-photopeak window (DPW) method, the image contrast of the five cold spheres is improved in the range of 2.7-26%.The RNB for all of the scatter correction methods is ranged from minimum 0.03 for DPW method to maximum 0.0727 for the three energy window (TEW) method using trapezoidal approximation.The TEW method using triangular approximation because of ease of implementation, good improvement of the image contrast and the SNR for the five cold spheres, and the low noise level is proposed as most appropriate correction method.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Faculty of Sciences, University of Guilan, Rasht, Iran.

ABSTRACT
Compton-scattered photons included within the photopeak pulse-height window result in the degradation of SPECT images both qualitatively and quantitatively. The purpose of this study is to evaluate and compare six scatter correction methods based on setting the energy windows in (99m)Tc spectrum. SIMIND Monte Carlo simulation is used to generate the projection images from a cold-sphere hot-background phantom. For evaluation of different scatter correction methods, three assessment criteria including image contrast, signal-to-noise ratio (SNR) and relative noise of the background (RNB) are considered. Except for the dual-photopeak window (DPW) method, the image contrast of the five cold spheres is improved in the range of 2.7-26%. Among methods considered, two methods show a nonuniform correction performance. The RNB for all of the scatter correction methods is ranged from minimum 0.03 for DPW method to maximum 0.0727 for the three energy window (TEW) method using trapezoidal approximation. The TEW method using triangular approximation because of ease of implementation, good improvement of the image contrast and the SNR for the five cold spheres, and the low noise level is proposed as most appropriate correction method.

No MeSH data available.


Related in: MedlinePlus

Plot of SUR(i,j) against R(i,j) for a typical projection. Each point corresponds to a pixel (i,j) in the projection image. The solid line corresponds to the nonlinear regression fitting SUR(i,j) = A[R(i,j)]B + C
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Figure 4: Plot of SUR(i,j) against R(i,j) for a typical projection. Each point corresponds to a pixel (i,j) in the projection image. The solid line corresponds to the nonlinear regression fitting SUR(i,j) = A[R(i,j)]B + C

Mentions: Using the photopeak scatter and scatter-free projections generated by SIMIND Monte Carlo simulation, it is possible to calculate the ratio of the photopeak scatter counts to the photopeak unscatter counts (scatter fraction) for each pixel, SUR(i,j). The plot of the SUR(i,j) against R(i,j) for a typical projection has been shown in Figure 4. The values of parameters A, B, and C resulting from the nonlinear regression fitting for the projection’s ROI are −0.276, −1.429, and 0.4595, respectively.


Evaluation of six scatter correction methods based on spectral analysis in (99m)Tc SPECT imaging using SIMIND Monte Carlo simulation.

Asl MN, Sadremomtaz A, Bitarafan-Rajabi A - J Med Phys (2013)

Plot of SUR(i,j) against R(i,j) for a typical projection. Each point corresponds to a pixel (i,j) in the projection image. The solid line corresponds to the nonlinear regression fitting SUR(i,j) = A[R(i,j)]B + C
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3958999&req=5

Figure 4: Plot of SUR(i,j) against R(i,j) for a typical projection. Each point corresponds to a pixel (i,j) in the projection image. The solid line corresponds to the nonlinear regression fitting SUR(i,j) = A[R(i,j)]B + C
Mentions: Using the photopeak scatter and scatter-free projections generated by SIMIND Monte Carlo simulation, it is possible to calculate the ratio of the photopeak scatter counts to the photopeak unscatter counts (scatter fraction) for each pixel, SUR(i,j). The plot of the SUR(i,j) against R(i,j) for a typical projection has been shown in Figure 4. The values of parameters A, B, and C resulting from the nonlinear regression fitting for the projection’s ROI are −0.276, −1.429, and 0.4595, respectively.

Bottom Line: Except for the dual-photopeak window (DPW) method, the image contrast of the five cold spheres is improved in the range of 2.7-26%.The RNB for all of the scatter correction methods is ranged from minimum 0.03 for DPW method to maximum 0.0727 for the three energy window (TEW) method using trapezoidal approximation.The TEW method using triangular approximation because of ease of implementation, good improvement of the image contrast and the SNR for the five cold spheres, and the low noise level is proposed as most appropriate correction method.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Faculty of Sciences, University of Guilan, Rasht, Iran.

ABSTRACT
Compton-scattered photons included within the photopeak pulse-height window result in the degradation of SPECT images both qualitatively and quantitatively. The purpose of this study is to evaluate and compare six scatter correction methods based on setting the energy windows in (99m)Tc spectrum. SIMIND Monte Carlo simulation is used to generate the projection images from a cold-sphere hot-background phantom. For evaluation of different scatter correction methods, three assessment criteria including image contrast, signal-to-noise ratio (SNR) and relative noise of the background (RNB) are considered. Except for the dual-photopeak window (DPW) method, the image contrast of the five cold spheres is improved in the range of 2.7-26%. Among methods considered, two methods show a nonuniform correction performance. The RNB for all of the scatter correction methods is ranged from minimum 0.03 for DPW method to maximum 0.0727 for the three energy window (TEW) method using trapezoidal approximation. The TEW method using triangular approximation because of ease of implementation, good improvement of the image contrast and the SNR for the five cold spheres, and the low noise level is proposed as most appropriate correction method.

No MeSH data available.


Related in: MedlinePlus