A High-Resolution Time-of-Flight Clinical PET Detection System Using a Gapless PMT-Quadrant-Sharing Method

Wong, Wai-Hoi; Li, Hongdi; Zhang, Yuxuan; Ramirez, Rocio; An, Shaohui; Wang, Chao; Liu, Shitao; Dong, Yun; Baghaei, H.

doi:10.1109/tns.2015.2455511

Cited by 11 publications

(9 citation statements)

References 28 publications

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“…For the Philips Vereos TOF-PET/CT scanner, which is based on arrays of 4 mm × 4 mm LYSO:Ce crystals coupled to the same DPC sensors as used in this work, an energy resolution of 11.1% FWHM has been reported (Miller et al 2015). Similar values have been reported for other prototype detectors and scanners based on pixelated crystals coupled to DPC sensors (Degenhardt et al 2012, Marcinkowski et al 2014, Schug et al 2015 or PMTs (Wong et al 2015), which achieved energy resolutions between 10.7% FWHM and 11.4% FWHM. The slightly improved energy resolution of monolithic scintillator detectors compared to pixelated detector, when the same type of photosensor is used, can be explained by the more efficient light collection process due to the favorable aspect ratio of monolithic crystals.…”

Section: Energy Resolution and Coincidence Resolving Timesupporting

confidence: 86%

Sub-3 mm, near-200 ps TOF/DOI-PET imaging with monolithic scintillator detectors in a 70 cm diameter tomographic setup

et al. 2018

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Recently, a monolithic scintillator detector for time-of-flight (TOF)/depth-of-interaction (DOI) positron emission tomography (PET) was developed. It has a detector spatial resolution of ~1.7 mm full-width-at-half-maximum (FWHM), a coincidence resolving time (CRT) of ~215 ps FWHM, and ~4.7 mm FWHM DOI resolution. Here, we demonstrate, for the first time, the imaging performance of this detector in a 70 cm diameter PET geometry. We built a tomographic setup representative of a whole-body clinical scanner, comprising two coaxially rotating arms, each carrying a detector module, and a central, rotating phantom table. The fully automated setup sequentially acquires all possible lines of response (LORs) of a complete detector ring, using a step-and-shoot acquisition approach. The modules contained 2 × 2 detectors, each detector consisting of a 32 mm × 32 mm × 22 mm LYSO crystal and a digital silicon photomultiplier (dSiPM) array. The system spatial resolution was assessed using a Na-22 point source at different radial distances in the field-of-view (FOV). Using 2D filtered back projection (2D FBP, non-TOF), tangential and radial spatial resolutions of ~2.9 mm FWHM were obtained at the center of the FOV. The use of DOI information resulted in almost uniform spatial resolution throughout the FOV up to a radial distance of 25 cm, where the radial and tangential resolution are ~3.3 mm FWHM and ~4.7 mm FWHM, respectively, whereas without DOI the resolution deteriorates to ~9 mm FWHM. Additional measurements were performed with a Na-22 filled Derenzo-like phantom at different locations within the FOV. Images reconstructed with a TOF maximum-likelihood expectation-maximization (TOF ML-EM) algorithm show that the system is able to clearly resolve 3 mm diameter hot rods up to 25 cm radial distance. The excellent and uniform spatial resolution, combined with an energy resolution of 10.2% FWHM and a CRT of ~212 ps FWHM, indicates a great potential for monolithic scintillators as practical high-performance detectors in TOF/DOI-PET systems.

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Section: Energy Resolution and Coincidence Resolving Timesupporting

confidence: 86%

Sub-3 mm, near-200 ps TOF/DOI-PET imaging with monolithic scintillator detectors in a 70 cm diameter tomographic setup

et al. 2018

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“…To demonstrate that the proposed algorithm can be applied to fully 3D PET data, GATE simulations were performed to generate fully 3D TOF emission and Lu‐176 background data based on a uMI510 TOF PET scanner (United Imaging Healthcare, Shanghai, China) and the 3D NCAT phantom (Fig. ).…”

Section: Methodsmentioning

confidence: 99%

Maximum likelihood activity and attenuation estimation using both emission and transmission data with application to utilization of Lu‐176 background radiation in TOF PET

Zhang

et al. 2020

Medical Physics

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Purpose We present a new method for joint reconstruction of activity and attenuation images using both emission and transmission data and demonstrate its advantage over the standard maximum likelihood activity and attenuation (MLAA) reconstruction using emission data alone. Methods We define a joint likelihood function including both time‐of‐flight (TOF) emission data and transmission data. The latter can be obtained from an external source or from Lu‐176 background radiation. Activity and attenuation images are estimated jointly by maximizing the likelihood function. The proposed method solves the undetermined scale problem in the conventional MLAA. A monotonically convergent algorithm was derived to optimize the objective function. Furthermore, we present a theoretical analysis of the noise propagation in the joint reconstruction. Simulations and phantom experiments were conducted to validate the feasibility of the proposed method. Results Quantitatively correct and less noisy images were reconstructed with the proposed method. Artifacts in the attenuation map reconstructed from the standard MLAA were removed by incorporating transmission data. Noise analysis was validated with different transmission sources and transmission count levels. The theoretical prediction indicated that noise of activity map would not change in a large range of transmission count level and a very low transmission count level could result in good estimation. Conclusions The results demonstrate the feasibility of obtaining quantitatively correct images in TOF PET by using both emission and (weak) transmission data. The noise analysis also provides guidance for choosing a proper transmission source configuration to reduce noise propagation.

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“…Besides the conventional PET detector, in which one PMT is only used for decoding one crystal block, a PET detector using a PMT-Quadrant-Sharing (PQS) configuration was developed [31,32,33]. In the PQS configuration, only a quadrant of the PMT was used to decode the crystal block, resulting in higher decoding resolution (the ratio of numbers of crystals in the whole system to the numbers of PMTs in the whole system).…”

Section: Photomultiplier Tubes (Pmts)mentioning

confidence: 99%

“…Another PET detector made by coupling a 13 × 13 LYSO array of small size (1.4 × 1.4 × 10 mm 3 ) onto a small Photonis XP1912 PMT was measured to achieve a FWHM CRT of 551 ps. A whole PET system for human imaging using the PQS configuration was reported in [33]. The detector ring was made up of 24 detector panels with an axial field-of-view (FoV) of 27.6 cm and a ring diameter of 87 cm.…”

Section: Photomultiplier Tubes (Pmts)mentioning

confidence: 99%

Sensors for Positron Emission Tomography Applications

Jiang

Chalich

Deen

2019

Sensors

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Positron emission tomography (PET) imaging is an essential tool in clinical applications for the diagnosis of diseases due to its ability to acquire functional images to help differentiate between metabolic and biological activities at the molecular level. One key limiting factor in the development of efficient and accurate PET systems is the sensor technology in the PET detector. There are generally four types of sensor technologies employed: photomultiplier tubes (PMTs), avalanche photodiodes (APDs), silicon photomultipliers (SiPMs), and cadmium zinc telluride (CZT) detectors. PMTs were widely used for PET applications in the early days due to their excellent performance metrics of high gain, low noise, and fast timing. However, the fragility and bulkiness of the PMT glass tubes, high operating voltage, and sensitivity to magnetic fields ultimately limit this technology for future cost-effective and multi-modal systems. As a result, solid-state photodetectors like the APD, SiPM, and CZT detectors, and their applications for PET systems, have attracted lots of research interest, especially owing to the continual advancements in the semiconductor fabrication process. In this review, we study and discuss the operating principles, key performance parameters, and PET applications for each type of sensor technology with an emphasis on SiPM and CZT detectors—the two most promising types of sensors for future PET systems. We also present the sensor technologies used in commercially available state-of-the-art PET systems. Finally, the strengths and weaknesses of these four types of sensors are compared and the research challenges of SiPM and CZT detectors are discussed and summarized.

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A High-Resolution Time-of-Flight Clinical PET Detection System Using a Gapless PMT-Quadrant-Sharing Method

Cited by 11 publications

References 28 publications

Sub-3 mm, near-200 ps TOF/DOI-PET imaging with monolithic scintillator detectors in a 70 cm diameter tomographic setup

Sub-3 mm, near-200 ps TOF/DOI-PET imaging with monolithic scintillator detectors in a 70 cm diameter tomographic setup

Maximum likelihood activity and attenuation estimation using both emission and transmission data with application to utilization of Lu‐176 background radiation in TOF PET

Sensors for Positron Emission Tomography Applications

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