OSEM-3D Reconstruction Strategies for the ECAT HRRT

Comtat, Claude; Bataille, Frédéric; Michel, Christian; Jones, J.P.; Sibomana, M.; Janeiro, L.; Trébossen, R.

doi:10.1109/nssmic.2004.1466639

Cited by 114 publications

(88 citation statements)

References 6 publications

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“…For each patient-true count combination, the highest possible number of independent realizations was generated and reconstructed, up to a maximum of 50. The reconstruction algorithm was ordinary Poisson ordered-subset expectation maximization (OSEM) (27,28), incorporating time-of-flight information and system resolution modeling, with 2 iterations, 21 subsets, and 3-mm smoothing, producing 400 · 400 image matrices with a voxel size of 2.04 · 2.04 · 2.03 mm. The CT images were 512 · 512 with a voxel size of 1.52 · 1.52 · 5 mm.…”

Section: Methodsmentioning

confidence: 99%

Quantitative Accuracy and Lesion Detectability of Low-Dose ¹⁸F-FDG PET for Lung Cancer Screening

et al. 2016

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Lung cancer remains responsible for more deaths worldwide than any other cancer, but recently there has been a significant shift in the clinical paradigm regarding the initial management of subjects at high risk for this disease. Low-dose CT has demonstrated significant improvements over planar x-ray screening for patient prognoses and is now performed in the United States. Specificity of this modality, however, is poor, and the additional information from PET has the potential to improve its accuracy. Routine screening requires consideration of the effective dose delivered to the patient, and this work investigates image quality of PET for low-dose conditions, in the context of lung lesion detectability. Reduced radiotracer doses were simulated by randomly discarding counts from clinical lung cancer scans acquired in list-mode. Bias and reproducibility of lesion activity values were relatively stable even at low total counts of around 5 million trues. Additionally, numeric observer models were developed and trained with the results of 2 physicians and 3 postdoctoral researchers with PET experience in a detection task; detection sensitivity of the observers was well correlated with lesion signal-to-noise ratio. The models were used prospectively to survey detectability of lung cancer lesions, and the findings suggested a lower limit around 10 million true counts for maximizing performance. Under the acquisition parameters used in this study, this translates to an effective patient dose of less than 0.4 mSv, potentially allowing a complete low-dose PET/CT lung screening scan to be obtained under 1 mSv.

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Section: Methodsmentioning

confidence: 99%

Quantitative Accuracy and Lesion Detectability of Low-Dose ¹⁸F-FDG PET for Lung Cancer Screening

et al. 2016

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“…PET data were acquired for 30 min, resulting in about 5 GB of raw data. PET datasets were reconstructed using an ordered-subset expectation maximization 3-dimensional (3D) algorithm (20). The attenuation maps were computed from 3D MRI datasets using an algorithm combining pattern recognition and atlas registration (21).…”

Section: Pet/mri Data Acquisitionmentioning

confidence: 99%

Hybrid PET/MRI of Intracranial Masses: Initial Experiences and Comparison to PET/CT

Boss¹,

Bisdas²,

Kolb³

et al. 2010

J Nucl Med

228

129

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Simultaneous PET and MRI using new hybrid PET/MRI systems promises optimal spatial and temporal coregistration of structural, functional, and molecular image data. In a pilot study of 10 patients with intracranial masses, the feasibility of tumor assessment using a PET/MRI system comprising lutetium oxyorthosilicate scintillators coupled to avalanche photodiodes was evaluated, and quantification accuracy was compared with conventional PET/CT datasets. Methods: All measurements were performed with a hybrid PET/MRI scanner consisting of a conventional 3-T MRI scanner in combination with an inserted MRI-compatible PET system. Attenuation correction of PET/MR images was computed from MRI datasets. Diagnoses at the time of referral were low-grade astrocytoma (n 5 2), suspicion of low-grade astrocytoma (n 5 1), anaplastic astrocytoma (World Health Organization grade III; n 5 1), glioblastoma (n 5 2), atypical neurocytoma (n 5 1), and meningioma (n 5 3). In the glial tumors, 11 C-methionine was used for PET; in the meningiomas, 68 Ga-DOTATOC was administered. Tumor-togray matter and tumor-to-white matter ratios were calculated for gliomas, and tracer uptake of meningiomas was referenced to nasal mucosa. PET/MRI was performed directly after clinically indicated PET/CT examination. Results: In all patients, the PET datasets showed similar diagnostic image quality on the hybrid PET/MRI and the PET/CT studies; however, slight streak artifacts were visible in coronal and sagittal sections when using the higher intrinsic resolution of the PET/MRI insert. Prefiltering of images with a 4-mm gaussian filter at a resolution comparable to that of the PET/CT system virtually eliminated these artifacts. Although acquisition of the PET/MR images started at 30-60 min after PET/CT (20.4-min half-life of 11 C) acquisition, the signal-to-noise ratio was good enough, thus underlining the high sensitivity of the PET insert, compared with whole-body PET systems. The computed tumor-to-reference tissue ratios exhibited an excellent accordance between the PET/MRI and PET/CT systems, with a Pearson correlation coefficient of 0.98. Mean paired relative error was 7.9% 6 12.2%. No significant artifacts or distortions were detected in the simultaneously acquired MR images using the PET/MRI scanner. Conclusion: Structural, functional, and molecular imaging in patients with brain tumors is feasible with diagnostic imaging quality using simultaneous hybrid PET/MR image acquisition.

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“…Emission data were acquired in list mode and histogrammed using axial compression of span 9, yielding noise -equivalent counts in the range of 3 Â 10 6 to 2.5 Â 10 7 , except in the first frame. Image estimates with isotropic voxel dimensions of 1.22 Â 1.22 Â 1.22 mm 3 were generated using speed-optimized version of OP-OSEM-3D (Ordinary Poisson-OSEM in full 3D) reconstruction (Comtat et al, 2004;Hong et al, 2007) with 16 subsets and 8 full iterations.…”

Section: Positron Emission Tomography Proceduresmentioning

confidence: 99%

Measurement of Striatal and Extrastriatal Dopamine Transporter Binding with High-Resolution PET and [¹¹C]PE2I: Quantitative Modeling and Test—Retest Reproducibility

Hirvonen

Johansson

Teräs

et al. 2008

J Cereb Blood Flow Metab

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PE2I is a novel positron emission tomography (PET) radiotracer for the dopamine transporter (DAT). The reproducibility and reliability of [ 11 C]PE2I measurements, especially in the small DAT-rich brain regions, is unknown and of critical importance to the interpretation of the data. Five healthy volunteers were scanned twice during the same day using [11 C]PE2I and the HRRT PET scanner. Methods based on metabolite-corrected arterial plasma curve and reference region were used to estimate distribution volumes (V T ) and binding potential (BP). Within-subject and between-subject variabilities were compared. [11 C]PE2I accumulated in the DAT-rich striatum and the midbrain. Equilibrium of specific binding appeared late in the striatum, whereas it was reached earlier in the midbrain. Plasma metabolite analysis showed that the potentially brain-penetrant 4-hydroxymethyl metabolite represented 15% to 20% of total plasma radioactivity. V T and BP measurements were associated with low within-subject variability. Measurement of DAT binding in small brain regions, including the substantia nigra, is reproducible and reliable using [11 C]PE2I and high-resolution research tomograph. A scanning time of more than 70 mins is required for the striatum, while less is sufficient for DAT quantification in the midbrain. The previously suggested involvement of the potentially brain-penetrant radioactive metabolite in the quantification should be further studied.

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OSEM-3D Reconstruction Strategies for the ECAT HRRT

Cited by 114 publications

References 6 publications

Quantitative Accuracy and Lesion Detectability of Low-Dose ¹⁸F-FDG PET for Lung Cancer Screening

Quantitative Accuracy and Lesion Detectability of Low-Dose ¹⁸F-FDG PET for Lung Cancer Screening

Hybrid PET/MRI of Intracranial Masses: Initial Experiences and Comparison to PET/CT

Measurement of Striatal and Extrastriatal Dopamine Transporter Binding with High-Resolution PET and [¹¹C]PE2I: Quantitative Modeling and Test—Retest Reproducibility

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OSEM-3D Reconstruction Strategies for the ECAT HRRT

Cited by 114 publications

References 6 publications

Quantitative Accuracy and Lesion Detectability of Low-Dose 18F-FDG PET for Lung Cancer Screening

Quantitative Accuracy and Lesion Detectability of Low-Dose 18F-FDG PET for Lung Cancer Screening

Hybrid PET/MRI of Intracranial Masses: Initial Experiences and Comparison to PET/CT

Measurement of Striatal and Extrastriatal Dopamine Transporter Binding with High-Resolution PET and [11C]PE2I: Quantitative Modeling and Test—Retest Reproducibility

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Quantitative Accuracy and Lesion Detectability of Low-Dose ¹⁸F-FDG PET for Lung Cancer Screening

Quantitative Accuracy and Lesion Detectability of Low-Dose ¹⁸F-FDG PET for Lung Cancer Screening

Measurement of Striatal and Extrastriatal Dopamine Transporter Binding with High-Resolution PET and [¹¹C]PE2I: Quantitative Modeling and Test—Retest Reproducibility