Comparison between new-generation SiPM-based and conventional PMT-based TOF-PET/CT

Wagatsuma, Kei; Miwa, Koichi; Sakata, Muneyuki; Oda, Kazuhiro; Ono, Haruka; Kameyama, Masashi; Toyohara, Jun; Ishii, Kenji

doi:10.1016/j.ejmp.2017.09.124

Cited by 84 publications

(91 citation statements)

References 41 publications

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“…The NEMA NU 2-2012 parameters measured for the 4-ring DMI system (AFOV = 20 cm) were compared with results obtained at Stanford and Uppsala Universities [2] and Tokyo [3] for the same system and with results from Brugge [4] obtained for the system in its 3-ring configuration (AFOV = 15 cm). For the DMI-DR system, results were compared with those obtained at Southampton-Poole-Plymouth [5].…”

Section: Comparisons With Other Studiesmentioning

confidence: 99%

“…It is noteworthy that the results for the two systems are similar with, for instance, a spatial resolution for DMI and DMI-DR of 4.62 vs 4.58 for FBP, 3.85 vs 4.13 for VPHD (3D OSEM) and 2.70 vs 2.84 for VPHD-S (3D OSEM + PSF) at 1-cm radial offset. For the DMI evaluation, the results obtained at our institution are compared with previous results from Stanford and Uppsala Universities [2], Tokyo [3] and Brugge [4] in Fig. 1a-c.…”

Section: Spatial Resolutionmentioning

confidence: 99%

“…The purposes of this work were to evaluate the physical performances of the SiPM-based 4-ring DMI and PMT-based DMI-DR PET/CT systems according to these standards and to compare their performance using the NEMA measurements. In addition, a comparison of NEMA data at our site with publicly available data for the 4-ring DMI system at Stanford and Uppsala Universities [2] and Tokyo [3] will be provided. A comparison with the 3-ring DMI system installed at Brugge [4] will be also presented.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of NEMA characterizations for Discovery MI and Discovery MI-DR TOF PET/CT systems at different sites and with other commercial PET/CT systems

Chicheportiche

Marciano²,

Orevi

2020

EJNMMI Phys

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Background: This article compares the physical performance of the 4-ring digital Discovery MI (DMI) and PMT-based Discovery MI-DR (DMI-DR) PET/CT systems. Physical performance was assessed according to the NEMA NU 2-2012 standards. Performance measures included spatial resolution, image quality, scatter fraction and count rate performance, and sensitivity. Energy and timing resolutions were also measured. Published DMI and DMI-DR performance studies from other centers are reviewed and compared. Results: 4-ring DMI spatial resolution at 1-cm radial offset in the radial, tangential and axial directions was 4.62, 4.18 and 4.57 mm, respectively, compared with the DMI-DR system values of 4.58, 4.52, and 5.31 mm. Measured sensitivity was 13.3 kcps/ MBq at the center of the FOV and 13.4 kcps/MBq 10 cm off-center for the SiPMbased DMI system. DMI-DR system sensitivity was 6.3 kcps/MBq at the center of the FOV and 6.8 kcps/MBq at 10 cm off-center. DMI measured noise equivalent count rate peak was 175.6 kcps at 20.1 kBq/ml; DMI-DR was 146.7 kcps at 31.7 kBq/ml. Scatter fraction was 40.5% and 36.6%, respectively. DMI image contrast recovery (CR) values ranged from 73.2% (10 mm sphere) to 91.0% (37 mm sphere); DMI-DR, values ranged from 68.4% to 91.4%. DMI background variability (BV) was 1.8%-6.5%; DMI-DR was 2.3%-9.1%. The Q.Clear algorithm improved image quality, increasing CR and decreasing BV in both systems. The photopeak energy resolution was 9.63% and 12.19% for DMI and DMI-DR, respectively. The time-of-flight (TOF) resolution was 377.26 ps and 552.71 ps, respectively. Compared with measurements in other centers, results were similar and showed an absolute mean relative deviation of 6% for DMI and 7% for DMI-DR overall performance results. Conclusions: Performance measures were higher for the 4-ring DMI than the DMI-DR system. The biggest advantages of the 4-ring DMI vs DMI-DR are improved sensitivity and count rate performance. This should allow a better image signal-tonoise ratio (SNR) for the same acquisition times or, similar SNR with lower acquisition times or injected activity. In its 3-ring configuration, the DMI showed worse performance results than the PMT-based system in terms of count rate scatter fraction and image quality (for similar axial FOV).

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Section: Comparisons With Other Studiesmentioning

confidence: 99%

Section: Spatial Resolutionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparison of NEMA characterizations for Discovery MI and Discovery MI-DR TOF PET/CT systems at different sites and with other commercial PET/CT systems

Chicheportiche

Marciano²,

Orevi

2020

EJNMMI Phys

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“…As a result, these detectors have seen over a decade of engineering 25,26 and broad applications in e.g. lidar 27 and medical imaging 28 .…”

Section: Introductionmentioning

confidence: 99%

Two-photon Imaging with Silicon Photomultipliers

Modi

Turner

Podgorski

2019

Preprint

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Silicon photomultipliers (SiPMs) are a class of inexpensive and robust single-pixel detectors with applications similar to photomultiplier tubes (PMTs). We performed side-by-side comparisons of recently-developed SiPMs and a GaAsP PMT for two-photon fluorescence imaging of neural activity. Despite higher dark counts, which limit their performance at low photon rates (<1/μs), SiPMs matched the signal-to-noise ratio of the GaAsP PMT at photon rates encountered in typical calcium imaging experiments due to their much lower pulse height variability. At higher photon rates and dynamic ranges encountered during high-speed two-photon voltage imaging, SiPMs significantly outperformed the GaAsP PMT.Photomultiplier tubes (PMTs) detect light using a photocathode, which emits electrons upon photon absorption 2 . Emitted electrons are accelerated under high voltage in vacuum to strike a series of dynodes coated in a secondary emission material 3 . Collisions with the dynodes release additional electrons, amplifying the photon signal into a detectable current pulse. The highestsensitivity PMTs available for visible imaging use Gallium-Arsenide-Phosphide (GaAsP) photocathodes with high quantum efficiencies (QE; >40%), although these photocathodes degrade with light exposure. Alkali photocathodes are also used, which do not degrade substantially but are less sensitive. PMT output pulses have highly variable amplitudes 4 because they rely on a series of low-gain stochastic amplification steps. PMTs are the most commonly used single-pixel light detectors in microscopy.Avalanche photodiodes (APDs) are light-sensitive semiconductor diodes to which a bias voltage is applied. Photon absorption generates electron-hole pairs, which are accelerated by the bias voltage, producing additional electron-hole pairs via impact ionization. At lower bias voltages, APDs operate in 'linear mode', in which each photon produces a pulse of current. At higher bias voltages, APDs operate in Geiger mode, in which runaway ionization produces a saturating signal, causing the APD to act as a photon-gated binary switch. In Geiger mode, additional simultaneously-arriving photons do not produce additional signal. The Geiger mode avalanche is quenched by active or passive circuits 5 , which cause the bias voltage to drop below breakdown then restore it, allowing another photon to be detected. Geiger mode APDs (also called SPADs) have excellent quantum efficiency (>80%) and lower pulse height variability than PMTs, but have small sensitive areas, making single SPADs inefficient for collecting the large etendue of emission light from scattering specimens.

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“…The physical performance of two PET systems [9], one based on new-generation detectors of digital silicon photomultipliers (SiPM) and the other one with PMT and TOF, were evaluated using NEMA NU 2 (published by the National Electrical Manufacturers Association (NEMA)), provided by the vendor for each PET/CT scanner, allowing reproducible and accepted measurement standards for evaluating the physical performance of PET systems [10]. The SiPM-PET/CT demonstrated higher sensitivity, better performance under high count-rate conditions and better image quality than the conventional PMT-PET/CT system.…”

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confidence: 99%

Digital PET/CT: a new intriguing chance for clinical nuclear medicine and personalized molecular imaging

Schillaci

Urbano

2019

Eur J Nucl Med Mol Imaging

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Clinical PET/CT is a well-known useful tool for the in vivo noninvasive quantitative imaging of physiologic and pathologic processes [1]. Actually, the key role of PET/CT in cancer staging and therapeutic responses to personalized treatments is well established; it is an essential imaging modality not only in oncology but also in neuroscience and in all the applications of molecular imaging. In recent years, there have been multiple advances in PET/CT scanners: new hardware, software, and acquisition methods to improve image quality [2]. Nevertheless, till now PET detectors have been mainly based on photomultiplier tubes (PMT), which have well-known advantages but also several limitations that affect, in particular, small lesions detection [3]. The introduction of digital detectors in PET/CT scanners may represent an important improvement in this diagnostic technology [4].In this issue of EJNMMI, Lopez-Mora et al.[5] present a step forward in this field, comparing image quality and lesion detection capability between a digital (d) and an analog (a) PET/CT system in 100 patients with oncologic diseases who were prospectively included in this study. The patients consecutively underwent a single day, dual imaging protocol (d and aPET/CT) after a i.v. injection of either FDG or fluorocholine. The first PET/CT was performed 60 min after the i.v. injection of the radiopharmaceutical, and the second imaging dataset was acquired with a mean time delay of 50 ± 14 min. In the patients referred for an initial assessment (n = 58), the dPET/CT was performed first, while in the patients who were evaluated for therapy monitoring, the aPET/CT was firstly acquired. Three nuclear medicine physicians evaluated image quality using a 4-point scale (−1, poor to 2, excellent) and detection capability by counting the number of lesions with increased uptake of the radiopharmaceutical. In 54% of patients, dPET/CT allowed a better image quality than aPET/ CT; in the remaining 46 patients, image quality did not significantly differ between both devices. Regarding lesion detection capability, dPET/CT was able to visualize lesions in three patients in whom the a system resulted negative; moreover, in 19 out of 80 cases which were positive at aPET/CT imaging, the dPET/CT detected more lesions. In these 22 patients, all the lesions visualized only by means of the dPET/CT were < 1 cm in size: eight were in the lungs, eight in lymph-nodes, six in the liver, four in bones, and one in seminal vesicles, in the breasts and in the skin, respectively. It is worth noting that dPET/CT changed staging in 32% of these patients (7 out of 22).In the same group of 100 oncological patients, another recent study was conducted to assess whether dPET/CT impact on the quantification of SUVmax in target lesions (the most metabolically active in each case) and in reference regions (liver and mediastinal blood pool) in comparison to aPET/CT [6]. The findings of this paper indicate that SUVmax of the target lesions and mediastinal blood pool measured by the d system w...

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Comparison between new-generation SiPM-based and conventional PMT-based TOF-PET/CT

Cited by 84 publications

References 41 publications

Comparison of NEMA characterizations for Discovery MI and Discovery MI-DR TOF PET/CT systems at different sites and with other commercial PET/CT systems

Comparison of NEMA characterizations for Discovery MI and Discovery MI-DR TOF PET/CT systems at different sites and with other commercial PET/CT systems

Two-photon Imaging with Silicon Photomultipliers

Digital PET/CT: a new intriguing chance for clinical nuclear medicine and personalized molecular imaging

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