Physical and clinical performance of the mCT time-of-flight PET/CT scanner

Jakoby, Bjoern; Bercier, Y.; Conti, Maurizio; Casey, Michael; Bendriem, B.; Townsend, David W.

doi:10.1088/0031-9155/56/8/004

Cited by 454 publications

(435 citation statements)

References 10 publications

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“…The delineated lesion is also shown in green in the figure. Consistent with the previous findings (22)(23)(24)(25)(26), OSEM 1 TOF 1 PSF produced visually the best image among the chosen 4 reconstruction algorithms with their default settings. In addition, quantitative assessment supported the fact that OSEM 1 TOF 1 PSF produced the best image with an SNR of 9.1 in the liver, whereas the SNR of OSEM, OSEM 1 PSF, and OSEM 1 TOF were 5.2, 5.5, and 8.5, respectively.…”

Section: Change Of Image Features Over Default Reconstruction Settingssupporting

confidence: 87%

“…Thus, the impact of the partial-volume effect can be neglected. Previous studies (22)(23)(24)(25)(26) demonstrated that OSEM 1 PSF 1 TOF produced better image quality than other methods in terms of SNR, contrast, and lesion detectability. Therefore, in this study, the tumor VOIs were delineated on the image reconstructed by OSEM 1 PSF 1 TOF with default settings and then applied to the other methods.…”

Section: Tumor Segmentationmentioning

confidence: 97%

“…However, only filtered backprojection and ordered-subset expectation maximization (OSEM) were investigated. The techniques of time-of-flight (TOF) and point-spread function (PSF) modeling have been shown to clearly improve image quality in terms of signal-to-noise ratio (SNR), lesion contrast, and coefficient of variation (COV) on background and are now standard in most scanners (22)(23)(24)(25)(26). TOF improves SNR and thus reduces heterogeneity due to noise.…”

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confidence: 99%

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Impact of Image Reconstruction Settings on Texture Features in ¹⁸F-FDG PET

et al. 2015

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Evaluation of tumor heterogeneity based on texture parameters has recently attracted much interest in the PET imaging community. However, the impact of reconstruction settings on texture parameters is unclear, especially relating to time-offlight and point-spread function modeling. Their effects on 55 texture features (TFs) and 6 features based on first-order statistics (FOS) were investigated. Standardized uptake value (SUV) measures were also evaluated as peak SUV (SUV peak ), maximum SUV, and mean SUV (SUV mean ). Methods: This study retrospectively recruited 20 patients with lesions in the lung who underwent whole-body 18 F-FDG PET/CT. The coefficient of variation (COV) of each feature across different reconstructions was calculated. Results: SUV peak , SUV mean , 18 TFs, and 1 FOS were the most robust (COV # 5%) whereas skewness, cluster shade, and zone percentage were the least robust (COV . 20%) with respect to reconstruction algorithms using default settings. Heterogeneity parameters had different sensitivities to iteration number. Twenty-four parameters including SUV peak and SUV mean exhibited variation with a COV less than 5%; 28 parameters, including maximum SUV, showed variation with a COV in the range of 5%-10%. In addition, skewness, cluster shade, and zone percentage were the most sensitive to iteration number. In terms of sensitivity to full width at half maximum (FWHM), 15 TFs and 1 FOS had the best performance with a COV less than 5%, whereas SUV peak and SUV mean had a COV between 5% and 10%. Grid size had the largest impact on image features, which was demonstrated by only 11 features, including SUV peak and SUV mean , having a COV less than 10%. Conclusion: Different image features have different sensitivities to reconstruction settings. Iteration number and FWHM of the gaussian filter have a similar impact on the image features. Grid size has a larger impact on the features than iteration number and FWHM. The features that exhibited large variations such as skewness in FOS, cluster shade, and zone percentage should be used with caution. The entropy in FOS, difference entropy, inverse difference normalized, inverse difference moment normalized, low gray-level run emphasis, high gray-level run emphasis, and low gray-level zone emphasis are the most robust features.

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Section: Change Of Image Features Over Default Reconstruction Settingssupporting

confidence: 87%

Section: Tumor Segmentationmentioning

confidence: 97%

mentioning

confidence: 99%

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Impact of Image Reconstruction Settings on Texture Features in ¹⁸F-FDG PET

et al. 2015

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“…However, we observed that TOF did not improve quantification of SUV, as shown by Jacoby et al [4], who also observed that the use of TOF produced substantially higher image contrast and signal-to-noise ratios.…”

Section: Discussionsupporting

confidence: 71%

Effect of reconstruction parameters and ROI definition on standardized uptake value quantification in tumors

Reynoso-Mejía

Rosas-Gozalez

Díaz-Meneses

et al. 2016

AIP Conference Proceedings

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Abstract. The purpose of this work was to evaluate the effect of reconstruction algorithms, reconstruction parameters and definition of region of interest (ROI) on the accuracy of standard uptake value (SUV) quantification. Measurements were performed on a Siemens Biograph mCT PET/CT using a Jaszczak phantom which contains spheres of different diameter filled with two sphere-to-background activity ratios. All data were reconstructed using FBP, OSEM, OSEM+PSF, OSEM+TOF and OSEM+PSF+TOF reconstruction algorithms. The variation of reconstruction parameters such as iteration numbers and FWHM of Gaussian filter was also evaluated. Different ROI definitions were used to measure SUV in each sphere: SUVave, SUVmax, SUV50 and SUVpeak. SUV accuracy was estimated with recovery coefficients (RC) for all settings. An increase in RCs of 40.7 ± 1.2% from sphere diameters of 10 mm to 28 mm and an increase of 6.3 ± 1.2% in RC values was obtained when PSF was applied. It was observed that RCs increased when iteration number increased; RCs decreased when FWHM increased. In ROI definition, SUVmax yielded an important overestimation of activity concentration (near 20%) when PSF was applied. SUV50 yielded similar values for all algorithms used, except for FBP. SUVpeak yielded values similar to the real ones (SUV~1) for all reconstructions, particularly when tumor size was > 17 mm. In conclusion, it was observed that the use of a higher iteration number, lower FWHM and the use of PSF reconstruction algorithm improved accuracy of SUV quantification. SUV50 and SUVpeak provided a more accurate quantification than SUVmax and could be proposed to replace it.

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“…We imaged four consenting patients under approved IRB (institutional review board) protocol, which followed patient imaging with whole‐body mCT PET/CT from Siemens (Jakoby et al., 2011). The patients (all male) were cancer patients requiring clinical whole‐body PET/CT.…”

Section: Methodsmentioning

confidence: 99%

Concept of an upright wearable positron emission tomography imager in humans

et al. 2016

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BackgroundPositron Emission Tomography (PET) is traditionally used to image patients in restrictive positions, with few devices allowing for upright, brain‐dedicated imaging. Our team has explored the concept of wearable PET imagers which could provide functional brain imaging of freely moving subjects. To test feasibility and determine future considerations for development, we built a rudimentary proof‐of‐concept prototype (Helmet_PET) and conducted tests in phantoms and four human volunteers.MethodsTwelve Silicon Photomultiplier‐based detectors were assembled in a ring with exterior weight support and an interior mechanism that could be adjustably fitted to the head. We conducted brain phantom tests as well as scanned four patients scheduled for diagnostic F18‐ FDG PET/CT imaging. For human subjects the imager was angled such that field of view included basal ganglia and visual cortex to test for typical resting‐state pattern. Imaging in two subjects was performed ~4 hr after PET/CT imaging to simulate lower injected F18‐ FDG dose by taking advantage of the natural radioactive decay of the tracer (F18 half‐life of 110 min), with an estimated imaging dosage of 25% of the standard.ResultsWe found that imaging with a simple lightweight ring of detectors was feasible using a fraction of the standard radioligand dose. Activity levels in the human participants were quantitatively similar to standard PET in a set of anatomical ROIs. Typical resting‐state brain pattern activation was demonstrated even in a 1 min scan of active head rotation.ConclusionTo our knowledge, this is the first demonstration of imaging a human subject with a novel wearable PET imager that moves with robust head movements. We discuss potential research and clinical applications that will drive the design of a fully functional device. Designs will need to consider trade‐offs between a low weight device with high mobility and a heavier device with greater sensitivity and larger field of view.

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Physical and clinical performance of the mCT time-of-flight PET/CT scanner

Cited by 454 publications

References 10 publications

Impact of Image Reconstruction Settings on Texture Features in ¹⁸F-FDG PET

Impact of Image Reconstruction Settings on Texture Features in ¹⁸F-FDG PET

Effect of reconstruction parameters and ROI definition on standardized uptake value quantification in tumors

Concept of an upright wearable positron emission tomography imager in humans

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Physical and clinical performance of the mCT time-of-flight PET/CT scanner

Cited by 454 publications

References 10 publications

Impact of Image Reconstruction Settings on Texture Features in 18F-FDG PET

Impact of Image Reconstruction Settings on Texture Features in 18F-FDG PET

Effect of reconstruction parameters and ROI definition on standardized uptake value quantification in tumors

Concept of an upright wearable positron emission tomography imager in humans

Contact Info

Product

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Impact of Image Reconstruction Settings on Texture Features in ¹⁸F-FDG PET

Impact of Image Reconstruction Settings on Texture Features in ¹⁸F-FDG PET