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Original research
Zhaowei Meng
Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin, China
Corresponding Author
ORCiD: https://orcid.org/0000-0002-4478-878X
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: To evaluate the impact of reconstruction parameters on spatial resolution of tomographic image in SPECT/CT, and to compare spatial resolution between a new polyvalent whole-body Cadmium-Zinc-Telluride camera (CZT-SPECT/CT) and a conventional dual-head Anger camera (conventional SPECT/CT). Spatial resolution was evaluated with four line sources filled with 99mTc in tomographic images reconstructed by varying reconstruction parameters. Ordered-subset expectation maximization (OSEM) algorithm was performed with varying iterations (1-20), the number of subsets was fixed at 10. Butterworth filter, Gauss filter and no-filter were selected respectively. Computed tomography-based attenuation correction (CTAC), scatter correction (SC), resolution recovery (RR) and no-correction (NC) were adopted for image correction respectively. Filtered back projection (FBP) with Butterworth filter and CTAC was also performed in image reconstruction. Spatial resolution was expressed by full width at half-maximum (FWHM) value.
Results: The impact of reconstruction parameters on spatial resolution was identical in both cameras: FWHM values decreased with the increase of iterations and converged uniformly when the number of iterations was over 4. FWHM values decreased with the increase of cutoff frequency of Butterworth filter and increased with the increase of Gauss filter. SC and RR improved spatial resolution, whereas CTAC had negligible effect on spatial resolution reconstructed by OSEM. FWHM was generally lower with OSEM reconstruction than FBP reconstruction. On the whole, under the same reconstruction conditions, CZT-SPECT/CT had a lower FWHM value than conventional SPECT/CT.
Conclusions: The spatial resolution was improved with the increase of iterations. Increasing the cutoff frequency of Butterworth filter and decreasing the Gauss filter enhanced spatial resolution. The spatial resolution was better reconstructed by OSEM associated with AC, SC and RR than FBP. CZT-SPECT/CT had better spatial resolution than conventional SPECT/CT.
Keywords
SPECT/CT, Cadmium-zinc-telluride (CZT), Spatial resolution, Reconstruction parameters
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This is a preprint. It has not completed peer review.
Original research
Zhaowei Meng
Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin, China
Corresponding Author
ORCiD: https://orcid.org/0000-0002-4478-878X
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 06 Apr, 2021
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: To evaluate the impact of reconstruction parameters on spatial resolution of tomographic image in SPECT/CT, and to compare spatial resolution between a new polyvalent whole-body Cadmium-Zinc-Telluride camera (CZT-SPECT/CT) and a conventional dual-head Anger camera (conventional SPECT/CT). Spatial resolution was evaluated with four line sources filled with 99mTc in tomographic images reconstructed by varying reconstruction parameters. Ordered-subset expectation maximization (OSEM) algorithm was performed with varying iterations (1-20), the number of subsets was fixed at 10. Butterworth filter, Gauss filter and no-filter were selected respectively. Computed tomography-based attenuation correction (CTAC), scatter correction (SC), resolution recovery (RR) and no-correction (NC) were adopted for image correction respectively. Filtered back projection (FBP) with Butterworth filter and CTAC was also performed in image reconstruction. Spatial resolution was expressed by full width at half-maximum (FWHM) value.
Results: The impact of reconstruction parameters on spatial resolution was identical in both cameras: FWHM values decreased with the increase of iterations and converged uniformly when the number of iterations was over 4. FWHM values decreased with the increase of cutoff frequency of Butterworth filter and increased with the increase of Gauss filter. SC and RR improved spatial resolution, whereas CTAC had negligible effect on spatial resolution reconstructed by OSEM. FWHM was generally lower with OSEM reconstruction than FBP reconstruction. On the whole, under the same reconstruction conditions, CZT-SPECT/CT had a lower FWHM value than conventional SPECT/CT.
Conclusions: The spatial resolution was improved with the increase of iterations. Increasing the cutoff frequency of Butterworth filter and decreasing the Gauss filter enhanced spatial resolution. The spatial resolution was better reconstructed by OSEM associated with AC, SC and RR than FBP. CZT-SPECT/CT had better spatial resolution than conventional SPECT/CT.
Figure 1
Figure 2
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Figure 4
Figure 5
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