Scatter and crosstalk corrections for 99mTc/123I dual-radionuclide imaging using a CZT SPECT system with pinhole collimators.
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| Title: | Scatter and crosstalk corrections for 99mTc/123I dual-radionuclide imaging using a CZT SPECT system with pinhole collimators. |
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| Authors: | Fan, Peng1, Hutton, Brian F.2, Holstensson, Maria3, Ljungberg, Michael4, Hendrik Pretorius, P.5, Prasad, Rameshwar6, Ma, Tianyu7, Liu, Yaqiang7, Wang, Shi7, Thorn, Stephanie L.8, Stacy, Mitchel R.8, Sinusas, Albert J.8, Liu, Chi6 |
| Source: | Medical Physics. Dec2015, Vol. 42 Issue 12, p6895-6911. 17p. |
| Subjects: | Cadmium zinc telluride, Pinhole cameras, Collimators, Single-photon emission computed tomography, Radionuclide imaging, Monte Carlo method |
| Abstract: | Purpose: The energy spectrum for a cadmium zinc telluride (CZT) detector has a low energy tail due to incomplete charge collection and intercrystal scattering. Due to these solid-state detector effects, scatter would be overestimated if the conventional triple-energy window (TEW) method is used for scatter and crosstalk corrections in CZT-based imaging systems. The objective of this work is to develop a scatter and crosstalk correction method for 99mTc/123I dual-radionuclide imaging for a CZT-based dedicated cardiac SPECT system with pinhole collimators (GE Discovery NM 530c/570c). Methods: A tailing model was developed to account for the low energy tail effects of the CZT detector. The parameters of the model were obtained using 99mTc and 123I point source measurements. A scatter model was defined to characterize the relationship between down-scatter and self-scatter projections. The parameters for this model were obtained from Monte Carlo simulation using SIMIND. The tailing and scatter models were further incorporated into a projection count model, and the primary and self-scatter projections of each radionuclide were determined with a maximum likelihood expectation maximization (MLEM) iterative estimation approach. The extracted scatter and crosstalk projections were then incorporated into MLEM image reconstruction as an additive term in forward projection to obtain scatter- and crosstalk-corrected images. The proposed method was validated using Monte Carlo simulation, line source experiment, anthropomorphic torso phantom studies, and patient studies. The performance of the proposed method was also compared to that obtained with the conventional TEW method. Results: Monte Carlo simulations and line source experiment demonstrated that the TEW method overestimated scatter while their proposed method provided more accurate scatter estimation by considering the low energy tail effect. In the phantom study, improved defect contrasts were observed with both correction methods compared to no correction, especially for the images of 99mTc in dualradionuclide imaging where there is heavy contamination from 123I. In this case, the nontransmural defect contrast was improved from 0.39 to 0.47 with the TEW method and to 0.51 with their proposed method and the transmural defect contrast was improved from 0.62 to 0.74 with the TEW method and to 0.73 with their proposed method. In the patient study, the proposed method provided higher myocardium-to-blood pool contrast than that of the TEW method. Similar to the phantom experiment, the improvement was the most substantial for the images of 99mTc in dual-radionuclide imaging. In this case, the myocardium-to-blood pool ratio was improved from 7.0 to 38.3 with the TEW method and to 63.6 with their proposed method. Compared to the TEW method, the proposed method also provided higher count levels in the reconstructed images in both phantom and patient studies, indicating reduced overestimation of scatter. Using the proposed method, consistent reconstruction results were obtained for both single-radionuclide data with scatter correction and dual-radionuclide data with scatter and crosstalk corrections, in both phantom and human studies. Conclusions: The authors demonstrate that the TEW method leads to overestimation in scatter and crosstalk for the CZT-based imaging system while the proposed scatter and crosstalk correction method can provide more accurate self-scatter and down-scatter estimations for quantitative singleradionuclide and dual-radionuclide imaging. [ABSTRACT FROM AUTHOR] |
| Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Items | – Name: Title Label: Title Group: Ti Data: Scatter and crosstalk corrections for <superscript>99m</superscript>Tc/<superscript>123</superscript>I dual-radionuclide imaging using a CZT SPECT system with pinhole collimators. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Fan%2C+Peng%22">Fan, Peng</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Hutton%2C+Brian+F%2E%22">Hutton, Brian F.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Holstensson%2C+Maria%22">Holstensson, Maria</searchLink><relatesTo>3</relatesTo><br /><searchLink fieldCode="AR" term="%22Ljungberg%2C+Michael%22">Ljungberg, Michael</searchLink><relatesTo>4</relatesTo><br /><searchLink fieldCode="AR" term="%22Hendrik+Pretorius%2C+P%2E%22">Hendrik Pretorius, P.</searchLink><relatesTo>5</relatesTo><br /><searchLink fieldCode="AR" term="%22Prasad%2C+Rameshwar%22">Prasad, Rameshwar</searchLink><relatesTo>6</relatesTo><br /><searchLink fieldCode="AR" term="%22Ma%2C+Tianyu%22">Ma, Tianyu</searchLink><relatesTo>7</relatesTo><br /><searchLink fieldCode="AR" term="%22Liu%2C+Yaqiang%22">Liu, Yaqiang</searchLink><relatesTo>7</relatesTo><br /><searchLink fieldCode="AR" term="%22Wang%2C+Shi%22">Wang, Shi</searchLink><relatesTo>7</relatesTo><br /><searchLink fieldCode="AR" term="%22Thorn%2C+Stephanie+L%2E%22">Thorn, Stephanie L.</searchLink><relatesTo>8</relatesTo><br /><searchLink fieldCode="AR" term="%22Stacy%2C+Mitchel+R%2E%22">Stacy, Mitchel R.</searchLink><relatesTo>8</relatesTo><br /><searchLink fieldCode="AR" term="%22Sinusas%2C+Albert+J%2E%22">Sinusas, Albert J.</searchLink><relatesTo>8</relatesTo><br /><searchLink fieldCode="AR" term="%22Liu%2C+Chi%22">Liu, Chi</searchLink><relatesTo>6</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Medical+Physics%22">Medical Physics</searchLink>. Dec2015, Vol. 42 Issue 12, p6895-6911. 17p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Cadmium+zinc+telluride%22">Cadmium zinc telluride</searchLink><br /><searchLink fieldCode="DE" term="%22Pinhole+cameras%22">Pinhole cameras</searchLink><br /><searchLink fieldCode="DE" term="%22Collimators%22">Collimators</searchLink><br /><searchLink fieldCode="DE" term="%22Single-photon+emission+computed+tomography%22">Single-photon emission computed tomography</searchLink><br /><searchLink fieldCode="DE" term="%22Radionuclide+imaging%22">Radionuclide imaging</searchLink><br /><searchLink fieldCode="DE" term="%22Monte+Carlo+method%22">Monte Carlo method</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Purpose: The energy spectrum for a cadmium zinc telluride (CZT) detector has a low energy tail due to incomplete charge collection and intercrystal scattering. Due to these solid-state detector effects, scatter would be overestimated if the conventional triple-energy window (TEW) method is used for scatter and crosstalk corrections in CZT-based imaging systems. The objective of this work is to develop a scatter and crosstalk correction method for 99mTc/123I dual-radionuclide imaging for a CZT-based dedicated cardiac SPECT system with pinhole collimators (GE Discovery NM 530c/570c). Methods: A tailing model was developed to account for the low energy tail effects of the CZT detector. The parameters of the model were obtained using 99mTc and 123I point source measurements. A scatter model was defined to characterize the relationship between down-scatter and self-scatter projections. The parameters for this model were obtained from Monte Carlo simulation using SIMIND. The tailing and scatter models were further incorporated into a projection count model, and the primary and self-scatter projections of each radionuclide were determined with a maximum likelihood expectation maximization (MLEM) iterative estimation approach. The extracted scatter and crosstalk projections were then incorporated into MLEM image reconstruction as an additive term in forward projection to obtain scatter- and crosstalk-corrected images. The proposed method was validated using Monte Carlo simulation, line source experiment, anthropomorphic torso phantom studies, and patient studies. The performance of the proposed method was also compared to that obtained with the conventional TEW method. Results: Monte Carlo simulations and line source experiment demonstrated that the TEW method overestimated scatter while their proposed method provided more accurate scatter estimation by considering the low energy tail effect. In the phantom study, improved defect contrasts were observed with both correction methods compared to no correction, especially for the images of 99mTc in dualradionuclide imaging where there is heavy contamination from 123I. In this case, the nontransmural defect contrast was improved from 0.39 to 0.47 with the TEW method and to 0.51 with their proposed method and the transmural defect contrast was improved from 0.62 to 0.74 with the TEW method and to 0.73 with their proposed method. In the patient study, the proposed method provided higher myocardium-to-blood pool contrast than that of the TEW method. Similar to the phantom experiment, the improvement was the most substantial for the images of 99mTc in dual-radionuclide imaging. In this case, the myocardium-to-blood pool ratio was improved from 7.0 to 38.3 with the TEW method and to 63.6 with their proposed method. Compared to the TEW method, the proposed method also provided higher count levels in the reconstructed images in both phantom and patient studies, indicating reduced overestimation of scatter. Using the proposed method, consistent reconstruction results were obtained for both single-radionuclide data with scatter correction and dual-radionuclide data with scatter and crosstalk corrections, in both phantom and human studies. Conclusions: The authors demonstrate that the TEW method leads to overestimation in scatter and crosstalk for the CZT-based imaging system while the proposed scatter and crosstalk correction method can provide more accurate self-scatter and down-scatter estimations for quantitative singleradionuclide and dual-radionuclide imaging. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1118/1.4934830 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 17 StartPage: 6895 Subjects: – SubjectFull: Cadmium zinc telluride Type: general – SubjectFull: Pinhole cameras Type: general – SubjectFull: Collimators Type: general – SubjectFull: Single-photon emission computed tomography Type: general – SubjectFull: Radionuclide imaging Type: general – SubjectFull: Monte Carlo method Type: general Titles: – TitleFull: Scatter and crosstalk corrections for 99mTc/123I dual-radionuclide imaging using a CZT SPECT system with pinhole collimators. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Fan, Peng – PersonEntity: Name: NameFull: Hutton, Brian F. – PersonEntity: Name: NameFull: Holstensson, Maria – PersonEntity: Name: NameFull: Ljungberg, Michael – PersonEntity: Name: NameFull: Hendrik Pretorius, P. – PersonEntity: Name: NameFull: Prasad, Rameshwar – PersonEntity: Name: NameFull: Ma, Tianyu – PersonEntity: Name: NameFull: Liu, Yaqiang – PersonEntity: Name: NameFull: Wang, Shi – PersonEntity: Name: NameFull: Thorn, Stephanie L. – PersonEntity: Name: NameFull: Stacy, Mitchel R. – PersonEntity: Name: NameFull: Sinusas, Albert J. – PersonEntity: Name: NameFull: Liu, Chi IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 12 Text: Dec2015 Type: published Y: 2015 Identifiers: – Type: issn-print Value: 00942405 Numbering: – Type: volume Value: 42 – Type: issue Value: 12 Titles: – TitleFull: Medical Physics Type: main |
| ResultId | 1 |
