Performance evaluation of a new high-sensitivity time-of-flight clinical PET/CT system

Huo, Li; Li, Nan; Wu, Heyu; Zhu, Wenjia; Xing, Haiqun; Ba, Jiantao; Wang, Tong; Li, Fang; Zhang, Hui

doi:10.1186/s40658-018-0229-4

Cited by 15 publications

(16 citation statements)

References 17 publications

(17 reference statements)

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“…Currently, a clinical evaluation of the whole-body PoleStar m660 TOF-PET/CT scanner is carried out [ 51 ]. The system is based on 3.63×3.63×20 mm 3 LYSO scintillators arranged into detector modules (14×14 crystals).…”

Section: Reviewmentioning

confidence: 99%

Recent developments in time-of-flight PET

et al. 2016

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While the first time-of-flight (TOF)-positron emission tomography (PET) systems were already built in the early 1980s, limited clinical studies were acquired on these scanners. PET was still a research tool, and the available TOF-PET systems were experimental. Due to a combination of low stopping power and limited spatial resolution (caused by limited light output of the scintillators), these systems could not compete with bismuth germanate (BGO)-based PET scanners. Developments on TOF system were limited for about a decade but started again around 2000. The combination of fast photomultipliers, scintillators with high density, modern electronics, and faster computing power for image reconstruction have made it possible to introduce this principle in clinical TOF-PET systems. This paper reviews recent developments in system design, image reconstruction, corrections, and the potential in new applications for TOF-PET. After explaining the basic principles of time-of-flight, the difficulties in detector technology and electronics to obtain a good and stable timing resolution are shortly explained. The available clinical systems and prototypes under development are described in detail. The development of this type of PET scanner also requires modified image reconstruction with accurate modeling and correction methods. The additional dimension introduced by the time difference motivates a shift from sinogram- to listmode-based reconstruction. This reconstruction is however rather slow and therefore rebinning techniques specific for TOF data have been proposed. The main motivation for TOF-PET remains the large potential for image quality improvement and more accurate quantification for a given number of counts. The gain is related to the ratio of object size and spatial extent of the TOF kernel and is therefore particularly relevant for heavy patients, where image quality degrades significantly due to increased attenuation (low counts) and high scatter fractions. The original calculations for the gain were based on analytical methods. Recent publications for iterative reconstruction have shown that it is difficult to quantify TOF gain into one factor. The gain depends on the measured distribution, the location within the object, and the count rate. In a clinical situation, the gain can be used to either increase the standardized uptake value (SUV) or reduce the image acquisition time or administered dose. The localized nature of the TOF kernel makes it possible to utilize local tomography reconstruction or to separate emission from transmission data. The introduction of TOF also improves the joint estimation of transmission and emission images from emission data only. TOF is also interesting for new applications of PET-like isotopes with low branching ratio for positron fraction. The local nature also reduces the need for fine angular sampling, which makes TOF interesting for limited angle situations like breast PET and online dose imaging in proton or hadron therapy. The aim of this review is to introduce the reader i...

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Section: Reviewmentioning

confidence: 99%

Recent developments in time-of-flight PET

et al. 2016

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“…All imaging was performed on a clinical PET-CT system [ 18 ] (PoleStar m660, Sinounion Healthcare Inc., Beijing, China) at PUMCH. 11 C-acetate was synthesized as described in literature [ 19 , 20 ].…”

Section: Methodsmentioning

confidence: 99%

Comparison among Reconstruction Algorithms for Quantitative Analysis of ¹¹C-Acetate Cardiac PET Imaging

Shi

Li²,

Ding

et al. 2018

Contrast Media & Molecular Imaging

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Objective Kinetic modeling of dynamic 11C-acetate PET imaging provides quantitative information for myocardium assessment. The quality and quantitation of PET images are known to be dependent on PET reconstruction methods. This study aims to investigate the impacts of reconstruction algorithms on the quantitative analysis of dynamic 11C-acetate cardiac PET imaging. Methods Suspected alcoholic cardiomyopathy patients (N = 24) underwent 11C-acetate dynamic PET imaging after low dose CT scan. PET images were reconstructed using four algorithms: filtered backprojection (FBP), ordered subsets expectation maximization (OSEM), OSEM with time-of-flight (TOF), and OSEM with both time-of-flight and point-spread-function (TPSF). Standardized uptake values (SUVs) at different time points were compared among images reconstructed using the four algorithms. Time-activity curves (TACs) in myocardium and blood pools of ventricles were generated from the dynamic image series. Kinetic parameters K1 and k2 were derived using a 1-tissue-compartment model for kinetic modeling of cardiac flow from 11C-acetate PET images. Results Significant image quality improvement was found in the images reconstructed using iterative OSEM-type algorithms (OSME, TOF, and TPSF) compared with FBP. However, no statistical differences in SUVs were observed among the four reconstruction methods at the selected time points. Kinetic parameters K1 and k2 also exhibited no statistical difference among the four reconstruction algorithms in terms of mean value and standard deviation. However, for the correlation analysis, OSEM reconstruction presented relatively higher residual in correlation with FBP reconstruction compared with TOF and TPSF reconstruction, and TOF and TPSF reconstruction were highly correlated with each other. Conclusion All the tested reconstruction algorithms performed similarly for quantitative analysis of 11C-acetate cardiac PET imaging. TOF and TPSF yielded highly consistent kinetic parameter results with superior image quality compared with FBP. OSEM was relatively less reliable. Both TOF and TPSF were recommended for cardiac 11C-acetate kinetic analysis.

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“…According to the Figure 9: Setup for the detection efficiency measurement. From left to right : the PbF 2 detection module (black squared block) with amplifiers PCB (green plate); the 22 Na radioactive source (transparent plastic disk); YAP spectrometer (black cylinder with the metallic ring).…”

Section: Efficiency Measurementmentioning

confidence: 99%

“…Measured and simulated spectra, produced by a 22 Na radioactive source in the YAP spectrometer. The pink histogram is the measured spectrum.…”

Section: Figure 10mentioning

confidence: 99%

Fast and efficient detection of 511 keV photons using Cherenkov light in PbF₂ crystal, coupled to a MCP-PMT and SAMPIC digitization module

et al. 2019

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A: We study the possibility to use the Cherenkov light for the efficient detection of 511 keV photons with the goal to use it in TOF-PET. We designed and tested two detection modules consisting of PbF 2 crystals attached to Planacon MCP-PMT XP85012. Amplified PMT signals are digitized by the SAMPIC module with high readout rate, up to 10 5 events/s, and a negligible contribution to the time resolution, below 20 ps (FWHM). We developed a fast 2D scanning system to calibrate the PMT time response and studied in details the timing characteristics of the Planacon PMT.Using a radioactive 22 Na source we measured a detection efficiency of 24% for 511 keV photons in a 10 mm thick crystal and a coincidence resolving time of 280 ps. We analyzed the main factors limiting the time resolution of the large-surface detection module and proposed solutions to improve it, which will be tested in our future project.

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Performance evaluation of a new high-sensitivity time-of-flight clinical PET/CT system

Cited by 15 publications

References 17 publications

Recent developments in time-of-flight PET

Recent developments in time-of-flight PET

Comparison among Reconstruction Algorithms for Quantitative Analysis of ¹¹C-Acetate Cardiac PET Imaging

Fast and efficient detection of 511 keV photons using Cherenkov light in PbF₂ crystal, coupled to a MCP-PMT and SAMPIC digitization module

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Performance evaluation of a new high-sensitivity time-of-flight clinical PET/CT system

Cited by 15 publications

References 17 publications

Recent developments in time-of-flight PET

Recent developments in time-of-flight PET

Comparison among Reconstruction Algorithms for Quantitative Analysis of 11C-Acetate Cardiac PET Imaging

Fast and efficient detection of 511 keV photons using Cherenkov light in PbF2 crystal, coupled to a MCP-PMT and SAMPIC digitization module

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Comparison among Reconstruction Algorithms for Quantitative Analysis of ¹¹C-Acetate Cardiac PET Imaging

Fast and efficient detection of 511 keV photons using Cherenkov light in PbF₂ crystal, coupled to a MCP-PMT and SAMPIC digitization module