PennPET Explorer: Design and Preliminary Performance of a Whole-Body Imager

Karp, Joel S.; Viswanath, Varsha; Geagan, Michael; Muehllehner, G.; Pantel, Austin R.; Parma, Michael J.; Perkins, Amy E.; Schmall, Jeffrey P.; Werner, Matthew E.; Daube-Witherspoon, Margaret E.

doi:10.2967/jnumed.119.229997

Cited by 156 publications

(138 citation statements)

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“…The general design of the PennPET whole-body imager has been previously described (9,10). Our companion paper provides additional details and describes initial testing of the system, performance measurements, and optimization for human imaging (6). Here, we briefly summarize the salient characteristics.…”

Section: Scanner Characteristicsmentioning

confidence: 99%

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PennPET Explorer: Human Imaging on a Whole-Body Imager

et al. 2019

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The PennPET Explorer, a prototype whole-body imager currently operating with a 64-cm axial field of view, can image the major body organs simultaneously with higher sensitivity than that of commercial devices. We report here the initial human imaging studies on the PennPET Explorer, with each study designed to test specific capabilities of the device. Methods: Healthy subjects were imaged with FDG on the PennPET Explorer. Subsequently, clinical subjects with disease were imaged with 18 F-FDG and 68 Ga-DOTATATE, and research subjects were imaged with experimental radiotracers. Results: We demonstrated the ability to scan for a shorter duration or, alternatively, with less activity, without a compromise in image quality. Delayed images, up to 10 half-lives with 18 F-FDG, revealed biologic insight and supported the ability to track biologic processes over time. In a clinical subject, the PennPET Explorer better delineated the extent of 18 F-FDG-avid disease. In a second clinical study with 68 Ga-DOTATATE, we demonstrated comparable diagnostic image quality between the PennPET scan and the clinical scan, but with one fifth the activity. Dynamic imaging studies captured relatively noise-free input functions for kinetic modeling approaches. Additional studies with experimental research radiotracers illustrated the benefits from the combination of large axial coverage and high sensitivity. Conclusion: These studies provided a proof of concept for many proposed applications for a PET scanner with a long axial field of view.

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Section: Scanner Characteristicsmentioning

confidence: 99%

“…To overcome these limitations, we have come together as the EXPLORER consortium to develop whole-body PET imaging devices (4,5). As part of this effort, we have developed the PennPET Explorer, a whole-body PET imager (6).…”

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PennPET Explorer: Human Imaging on a Whole-Body Imager

et al. 2019

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“…(7), is performed in the image space and not in the projection space. One of the benefits of processing in the image space is the possibility to include the information from Time of Flight (TOF) measurement [1,23]. Hence, a presented approach may be extended to PET scanners that provide TOF measurement.…”

Section: Total Variation Regularizationmentioning

confidence: 99%

“…Positron Emission Tomography (PET) is currently a key technique in the medical imaging area, which allows to diagnose functions of the organism and to track tumor changes. PET scanner consists of detector elements mounted on one or more rings, positioned so that it surrounds the patient [1][2][3]. Those detectors are used to register pairs of gamma quanta emitted back-to-back from patient's body.…”

Section: Introductionmentioning

confidence: 99%

Introduction of Total Variation Regularization into Filtered Backprojection Algorithm

Raczyński¹,

Wiślicki²,

Klimaszewski³

et al. 2017

Acta Phys. Pol. B

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In this paper we extend the state-of-the-art filtered backprojection (FBP) method with application of the concept of Total Variation regularization. We compare the performance of the new algorithm with the most common form of regularizing in the FBP image reconstruction via apodizing functions. The methods are validated in terms of cross-correlation coefficient between reconstructed and real image of radioactive tracer distribution using standard Derenzo-type phantom. We demonstrate that the proposed approach results in higher cross-correlation values with respect to the standard FBP method.

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“…developed a 70-cm long AFOV PET prototype, Penn-PET Explorer, by aligning three PET gantries interleaved by 7.6 cm axial gaps; no effect of the axial gaps on the image quality was shown. 20 In this study, we propose and validate, using realistic MC simulations, a cost-effective PET scanner prototype, Ex-mCT, with an AFOV of 43.6 cm, double that of the mCT scanner (21.8 cm). In contrast to the previous studies where detector sparsity was emulated by retrospectively zeroing the counts in selected detector elements within the PET gantry, here, the longer AFOV is attained by uniformly spacing out the detector rings over a larger axial distance.…”

Section: Introductionmentioning

confidence: 99%

Physical performance of a long axial field‐of‐view PET scanner prototype with sparse rings configuration: A Monte Carlo simulation study

et al. 2020

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Purpose: There is a growing interest in extending the axial fields-of-view (AFOV) of PET scanners. One major limitation for the widespread clinical adoption of such systems is the multifold increase in the associated material costs. In this study, we propose a cost-effective solution to extend the PET AFOV using a sparse detector rings configuration. The corresponding physical performance was validated using Monte Carlo simulations. Methods: Monte Carlo model of the Siemens Biograph TM mCT PET/CT, with a 21.8 cm AFOV and a set of compact rings of LSO crystals was developed as a gold standard. The mCT configuration was then modified by interleaving the LSO crystals in the axial direction within each detector block with 4 mm physical gaps (equivalent to the LSO crystal axial dimension) thus extending the AFOV to 43.6 cm (Ex-mCT). The physical performances of the two MC models were assessed and then compared using NEMA NU 2-2007 standards. Results: Ex-mCT showed <0.2 mm difference in transaxial spatial resolution, and, 0.8 mm and 0.3 mm deterioration in axial spatial resolution, compared to the mCT, at 1 and 10 cm off-center of the transaxial field-of-view respectively. The system sensitivities for the mCT and Ex-mCT models were 9.4 AE 0.2 and 10.75 AE 0.2 cps/kBq respectively. The higher sensitivity of Ex-mCT was due to four additional detector rings required to double the mCT AFOV. PET images of the NEMA Image Quality (IQ) phantom showed no artifacts due to detector rings sparsity, and all spheres were visible in both configurations. Ex-mCT achieved percent contrast recoveries within 5.6% of those of the mCT for all spheres and a maximum of 36% higher background variability at the center of the AFOV. The Ex-mCT, however, showed a more uniform noise distribution over an axial range of almost twice the length of the mCT AFOV. Conclusions: Using the proposed sparse detector-ring configuration, the AFOV of current generation PET systems can be doubled while maintaining the original number and volume of detector crystal elements, and without jeopardizing the system's overall physical performance. Despite an increase in the noise level, the Ex-mCT exhibited an improved noise uniformity.

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PennPET Explorer: Design and Preliminary Performance of a Whole-Body Imager

Cited by 156 publications

References 32 publications

PennPET Explorer: Human Imaging on a Whole-Body Imager

PennPET Explorer: Human Imaging on a Whole-Body Imager

Introduction of Total Variation Regularization into Filtered Backprojection Algorithm

Physical performance of a long axial field‐of‐view PET scanner prototype with sparse rings configuration: A Monte Carlo simulation study

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