A new algorithm for variance reduction on random coincidences (VRR) has been validated for the HR... more A new algorithm for variance reduction on random coincidences (VRR) has been validated for the HRRT. VRR is crucial to achieve quantitation for low statistics dynamic studies reconstructed with iterative methods based on ordinary Poisson model. On HRRT, VRR cannot be performed in projection space since individual LOR's are mixed after histogramming in parallel projection space using nearest neighbor approximation and axial compression. The proposed algorithm uses the classical random rate equation on the 4.5 109LOR's. However, crystal singles are registered at block level and have lower deadtime than coincidences. Variations in layer identification with countrate were reported biasing random estimation from block singles. Our method overcomes these problems by estimating the singles per crystal from delayed coincidences. A singles map is created histogramming every delayed event into 2 singles. Each element represents the number of coincidences between that crystal and the ones in the 5 opposite coincident heads. The algorithm finds iteratively the crystal singles rates compatible with the delayed coincidence events. The method has been validated on decaying phantoms. We compared estimated and measured block singles to identify deadtime difference between singles and coincidences
... Judson P. Jones, Member, IEEE, William F. Jones, Senior Member, IEEE, Frank Kehren, Danny F. ... more ... Judson P. Jones, Member, IEEE, William F. Jones, Senior Member, IEEE, Frank Kehren, Danny F. Newport, Member, IEEE, Johnny H. Reed, Mark W. Lenox, Ken Baker, Member, IEEE, Larry G. Byars, Christian Michel, Member, IEEE, Michael E. Casey, Senior Member, IEEE F ...
Abstract— In previous work we compared two parallel algorithms for calculating 3D forward and bac... more Abstract— In previous work we compared two parallel algorithms for calculating 3D forward and backprojection on a distributed-memory cluster computer. These two methods were used to develop an implementation of fully three-dimensional Ordered Subset Expectation Maximization ...
European Journal of Nuclear Medicine and Molecular Imaging, 1997
Spatial transformations of positron emission tomographic data for aligning images or transforming... more Spatial transformations of positron emission tomographic data for aligning images or transforming to standard anatomical space are usually performed with reconstructed images. However, they can also be performed during the reconstruction process, thereby interpolating the raw data fewer times. We investigated the performance of spatial transformations during reconstruction, implemented it in a standard 3D reconstruction algorithm, and tested it on phantom and patient H215O activation studies for the application of aligning both transmission and emission scans. Performing the transformations during reconstruction was shown to be equivalent to performing the transformations with reconstructed images for this particular application.
Abstract A dedicated whole human brain positron emission tomograph (PET), the High Resolution Res... more Abstract A dedicated whole human brain positron emission tomograph (PET), the High Resolution Research Tomograph (ECAT HRRT) is utilized to evaluate attenuation correction using single photon based transmission scanning. The patented transmission procedure ...
1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255), 1998
In order to characterize physiological cerebral activation or tissue response to a treatment, at ... more In order to characterize physiological cerebral activation or tissue response to a treatment, at least two FDG-PET studies are mandatory. In this work, a study of one hour duration with two injections at 30 min apart is reported. The separation of the two input curves (IC) consisted of fitting the blood curve corresponding to the first injection using spectral analysis,
2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC), 2009
THE Siemens HRRT scanner is a complex PET tomograph, using 8 LSO/LYSO panel detectors and Depth O... more THE Siemens HRRT scanner is a complex PET tomograph, using 8 LSO/LYSO panel detectors and Depth Of Interaction(DOI) with a total of 119908 detector crystals. The Direct Normalization (DN) is the standard method used for sinogram-mode reconstruction. This paper investigates the use of an improved component-based normalization method for HRRT sinogram reconstruction. This method is originally used for MOLAR LOR
European Journal of Nuclear Medicine and Molecular Imaging, 2003
Several yttrium-90 labelled somatostatin analogues are now available for cancer radiotherapy. Aft... more Several yttrium-90 labelled somatostatin analogues are now available for cancer radiotherapy. After injection, a large amount of the compound is excreted via the urinary tract, while a variable part is trapped in the tumour(s), allowing the curative effect. Unfortunately, the compound may also be trapped in critical tissues such as kidney or bone marrow. As a consequence, a method for assessment of individual biodistribution and pharmacokinetics is required to predict the maximum dose that can be safely injected into patients. However, (90)Y, a pure beta(-)particle emitter, cannot be used for quantitative imaging. Yttrium-86 is a positron emitter that allows imaging of tissue uptake using a PET camera. In addition to the positron, (86)Y also emits a multitude of prompt single gamma-rays, leading to significant overestimation of uptake when using classical reconstruction methods. We propose a patient-dependent correction method based on sinogram tail fitting using an (86)Y point spread function library. When applied to abdominal phantom acquisition data, the proposed correction method significantly improved the accuracy of the quantification: the initial overestimation of background activity by 117% was reduced to 9%, while the initial error in respect of kidney uptake by 84% was reduced to 5%. In patient studies, the mean discrepancy between PET total body activity and the activity expected from urinary collections was reduced from 92% to 7%, showing the benefit of the proposed correction method.
1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255), 1998
... The second algorithm, FOREX, is an exact rebinning algorithm which was first suggested, but n... more ... The second algorithm, FOREX, is an exact rebinning algorithm which was first suggested, but not implemented, ... 4). The exact reconstruction algorithm FOREX has been shown to have similar accuracy as 3DRP and is about 6 times faster. ...
Quantitative estimation of brain glucose metabolism (rCMRGlc) with positron emission tomography a... more Quantitative estimation of brain glucose metabolism (rCMRGlc) with positron emission tomography and fluorodeoxyglucose involves arterial blood sampling to estimate the delivery of radioactivity to the brain. Usually, for an intravenous injection of 30 s duration, an accurate input curve requires a frequency of one sample every 5 s or less to determine the peak activity in arterial plasma during the first 2 min after injection. In this work, 13 standardized sampling times were shown to be sufficient to accurately define the input curve. This standardized input curve was subsequently fitted by a polynomial function for its rising part and by spectral analysis for its decreasing part. Using the measured, the standardized, and the fitted input curves, rCMRGlc was estimated in 32 cerebral regions of interest in 20 normal volunteers. Comparison of rCMRGlc values obtained with the measured and the fitted input curves showed that both procedures gave consistent results, with a maximal relative error in mean rCMRGlc of 1% when using the autoradiographic method and 2% using kinetic analysis of dynamic data. This input-curve-fitting technique, which is not dependent on the peak time occurrence, allows an accurate determination of the input-curve shape from reduced sampling schemes.
European Journal of Nuclear Medicine and Molecular Imaging, 2003
Several yttrium-90 labelled somatostatin analogues are now available for cancer radiotherapy. Aft... more Several yttrium-90 labelled somatostatin analogues are now available for cancer radiotherapy. After injection, a large amount of the compound is excreted via the urinary tract, while a variable part is trapped in the tumour(s), allowing the curative effect. Unfortunately, the compound may also be trapped in critical tissues such as kidney or bone marrow. As a consequence, a method for assessment of individual biodistribution and pharmacokinetics is required to predict the maximum dose that can be safely injected into patients. However, (90)Y, a pure beta(-)particle emitter, cannot be used for quantitative imaging. Yttrium-86 is a positron emitter that allows imaging of tissue uptake using a PET camera. In addition to the positron, (86)Y also emits a multitude of prompt single gamma-rays, leading to significant overestimation of uptake when using classical reconstruction methods. We propose a patient-dependent correction method based on sinogram tail fitting using an (86)Y point spread function library. When applied to abdominal phantom acquisition data, the proposed correction method significantly improved the accuracy of the quantification: the initial overestimation of background activity by 117% was reduced to 9%, while the initial error in respect of kidney uptake by 84% was reduced to 5%. In patient studies, the mean discrepancy between PET total body activity and the activity expected from urinary collections was reduced from 92% to 7%, showing the benefit of the proposed correction method.
1995 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, 1995
A set of applications has been developed for volumic medical image display and analysis in PET an... more A set of applications has been developed for volumic medical image display and analysis in PET and MRI. Although the set may appear at first glance, as a implementation in X-Windows of a package previously developed at CTI under SunView, major improvements have been added to its functionality. All graphical user interfaces have been developed with InterViews, a public domain
A new algorithm for variance reduction on random coincidences (VRR) has been validated for the HR... more A new algorithm for variance reduction on random coincidences (VRR) has been validated for the HRRT. VRR is crucial to achieve quantitation for low statistics dynamic studies reconstructed with iterative methods based on ordinary Poisson model. On HRRT, VRR cannot be performed in projection space since individual LOR's are mixed after histogramming in parallel projection space using nearest neighbor approximation and axial compression. The proposed algorithm uses the classical random rate equation on the 4.5 109LOR's. However, crystal singles are registered at block level and have lower deadtime than coincidences. Variations in layer identification with countrate were reported biasing random estimation from block singles. Our method overcomes these problems by estimating the singles per crystal from delayed coincidences. A singles map is created histogramming every delayed event into 2 singles. Each element represents the number of coincidences between that crystal and the ones in the 5 opposite coincident heads. The algorithm finds iteratively the crystal singles rates compatible with the delayed coincidence events. The method has been validated on decaying phantoms. We compared estimated and measured block singles to identify deadtime difference between singles and coincidences
... Judson P. Jones, Member, IEEE, William F. Jones, Senior Member, IEEE, Frank Kehren, Danny F. ... more ... Judson P. Jones, Member, IEEE, William F. Jones, Senior Member, IEEE, Frank Kehren, Danny F. Newport, Member, IEEE, Johnny H. Reed, Mark W. Lenox, Ken Baker, Member, IEEE, Larry G. Byars, Christian Michel, Member, IEEE, Michael E. Casey, Senior Member, IEEE F ...
Abstract— In previous work we compared two parallel algorithms for calculating 3D forward and bac... more Abstract— In previous work we compared two parallel algorithms for calculating 3D forward and backprojection on a distributed-memory cluster computer. These two methods were used to develop an implementation of fully three-dimensional Ordered Subset Expectation Maximization ...
European Journal of Nuclear Medicine and Molecular Imaging, 1997
Spatial transformations of positron emission tomographic data for aligning images or transforming... more Spatial transformations of positron emission tomographic data for aligning images or transforming to standard anatomical space are usually performed with reconstructed images. However, they can also be performed during the reconstruction process, thereby interpolating the raw data fewer times. We investigated the performance of spatial transformations during reconstruction, implemented it in a standard 3D reconstruction algorithm, and tested it on phantom and patient H215O activation studies for the application of aligning both transmission and emission scans. Performing the transformations during reconstruction was shown to be equivalent to performing the transformations with reconstructed images for this particular application.
Abstract A dedicated whole human brain positron emission tomograph (PET), the High Resolution Res... more Abstract A dedicated whole human brain positron emission tomograph (PET), the High Resolution Research Tomograph (ECAT HRRT) is utilized to evaluate attenuation correction using single photon based transmission scanning. The patented transmission procedure ...
1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255), 1998
In order to characterize physiological cerebral activation or tissue response to a treatment, at ... more In order to characterize physiological cerebral activation or tissue response to a treatment, at least two FDG-PET studies are mandatory. In this work, a study of one hour duration with two injections at 30 min apart is reported. The separation of the two input curves (IC) consisted of fitting the blood curve corresponding to the first injection using spectral analysis,
2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC), 2009
THE Siemens HRRT scanner is a complex PET tomograph, using 8 LSO/LYSO panel detectors and Depth O... more THE Siemens HRRT scanner is a complex PET tomograph, using 8 LSO/LYSO panel detectors and Depth Of Interaction(DOI) with a total of 119908 detector crystals. The Direct Normalization (DN) is the standard method used for sinogram-mode reconstruction. This paper investigates the use of an improved component-based normalization method for HRRT sinogram reconstruction. This method is originally used for MOLAR LOR
European Journal of Nuclear Medicine and Molecular Imaging, 2003
Several yttrium-90 labelled somatostatin analogues are now available for cancer radiotherapy. Aft... more Several yttrium-90 labelled somatostatin analogues are now available for cancer radiotherapy. After injection, a large amount of the compound is excreted via the urinary tract, while a variable part is trapped in the tumour(s), allowing the curative effect. Unfortunately, the compound may also be trapped in critical tissues such as kidney or bone marrow. As a consequence, a method for assessment of individual biodistribution and pharmacokinetics is required to predict the maximum dose that can be safely injected into patients. However, (90)Y, a pure beta(-)particle emitter, cannot be used for quantitative imaging. Yttrium-86 is a positron emitter that allows imaging of tissue uptake using a PET camera. In addition to the positron, (86)Y also emits a multitude of prompt single gamma-rays, leading to significant overestimation of uptake when using classical reconstruction methods. We propose a patient-dependent correction method based on sinogram tail fitting using an (86)Y point spread function library. When applied to abdominal phantom acquisition data, the proposed correction method significantly improved the accuracy of the quantification: the initial overestimation of background activity by 117% was reduced to 9%, while the initial error in respect of kidney uptake by 84% was reduced to 5%. In patient studies, the mean discrepancy between PET total body activity and the activity expected from urinary collections was reduced from 92% to 7%, showing the benefit of the proposed correction method.
1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255), 1998
... The second algorithm, FOREX, is an exact rebinning algorithm which was first suggested, but n... more ... The second algorithm, FOREX, is an exact rebinning algorithm which was first suggested, but not implemented, ... 4). The exact reconstruction algorithm FOREX has been shown to have similar accuracy as 3DRP and is about 6 times faster. ...
Quantitative estimation of brain glucose metabolism (rCMRGlc) with positron emission tomography a... more Quantitative estimation of brain glucose metabolism (rCMRGlc) with positron emission tomography and fluorodeoxyglucose involves arterial blood sampling to estimate the delivery of radioactivity to the brain. Usually, for an intravenous injection of 30 s duration, an accurate input curve requires a frequency of one sample every 5 s or less to determine the peak activity in arterial plasma during the first 2 min after injection. In this work, 13 standardized sampling times were shown to be sufficient to accurately define the input curve. This standardized input curve was subsequently fitted by a polynomial function for its rising part and by spectral analysis for its decreasing part. Using the measured, the standardized, and the fitted input curves, rCMRGlc was estimated in 32 cerebral regions of interest in 20 normal volunteers. Comparison of rCMRGlc values obtained with the measured and the fitted input curves showed that both procedures gave consistent results, with a maximal relative error in mean rCMRGlc of 1% when using the autoradiographic method and 2% using kinetic analysis of dynamic data. This input-curve-fitting technique, which is not dependent on the peak time occurrence, allows an accurate determination of the input-curve shape from reduced sampling schemes.
European Journal of Nuclear Medicine and Molecular Imaging, 2003
Several yttrium-90 labelled somatostatin analogues are now available for cancer radiotherapy. Aft... more Several yttrium-90 labelled somatostatin analogues are now available for cancer radiotherapy. After injection, a large amount of the compound is excreted via the urinary tract, while a variable part is trapped in the tumour(s), allowing the curative effect. Unfortunately, the compound may also be trapped in critical tissues such as kidney or bone marrow. As a consequence, a method for assessment of individual biodistribution and pharmacokinetics is required to predict the maximum dose that can be safely injected into patients. However, (90)Y, a pure beta(-)particle emitter, cannot be used for quantitative imaging. Yttrium-86 is a positron emitter that allows imaging of tissue uptake using a PET camera. In addition to the positron, (86)Y also emits a multitude of prompt single gamma-rays, leading to significant overestimation of uptake when using classical reconstruction methods. We propose a patient-dependent correction method based on sinogram tail fitting using an (86)Y point spread function library. When applied to abdominal phantom acquisition data, the proposed correction method significantly improved the accuracy of the quantification: the initial overestimation of background activity by 117% was reduced to 9%, while the initial error in respect of kidney uptake by 84% was reduced to 5%. In patient studies, the mean discrepancy between PET total body activity and the activity expected from urinary collections was reduced from 92% to 7%, showing the benefit of the proposed correction method.
1995 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, 1995
A set of applications has been developed for volumic medical image display and analysis in PET an... more A set of applications has been developed for volumic medical image display and analysis in PET and MRI. Although the set may appear at first glance, as a implementation in X-Windows of a package previously developed at CTI under SunView, major improvements have been added to its functionality. All graphical user interfaces have been developed with InterViews, a public domain
Uploads
Papers by Christian Michel