Walk-through flat panel total-body PET: a patient-centered design for high throughput imaging at lower cost using DOI-capable high-resolution monolithic detectors.
Vandenberghe, Stefaan; Muller, Florence M; Withofs, Nadiaet al.
2023 • In European Journal of Nuclear Medicine and Molecular Imaging
BGO; Cost-lifetime analysis; L(Y)SO; Monolithic detector; Patient throughput; Positron emission tomography; Total-body PET; Walk-through PET; Radiology, Nuclear Medicine and Imaging; General Medicine
Abstract :
[en] [en] PURPOSE: Long axial field-of-view (LAFOV) systems have a much higher sensitivity than standard axial field-of-view (SAFOV) PET systems for imaging the torso or full body, which allows faster and/or lower dose imaging. Despite its very high sensitivity, current total-body PET (TB-PET) throughput is limited by patient handling (positioning on the bed) and often a shortage of available personnel. This factor, combined with high system costs, makes it hard to justify the implementation of these systems for many academic and nearly all routine nuclear medicine departments. We, therefore, propose a novel, cost-effective, dual flat panel TB-PET system for patients in upright standing positions to avoid the time-consuming positioning on a PET-CT table; the walk-through (WT) TB-PET. We describe a patient-centered, flat panel PET design that offers very efficient patient throughput and uses monolithic detectors (with BGO or LYSO) with depth-of-interaction (DOI) capabilities and high intrinsic spatial resolution. We compare system sensitivity, component costs, and patient throughput of the proposed WT-TB-PET to a SAFOV (= 26 cm) and a LAFOV (= 106 cm) LSO PET systems.
METHODS: Patient width, height (= top head to start of thighs) and depth (= distance from the bed to front of patient) were derived from 40 randomly selected PET-CT scans to define the design dimensions of the WT-TB-PET. We compare this new PET system to the commercially available Siemens Biograph Vision 600 (SAFOV) and Siemens Quadra (LAFOV) PET-CT in terms of component costs, system sensitivity, and patient throughput. System cost comparison was based on estimating the cost of the two main components in the PET system (Silicon Photomultipliers (SiPMs) and scintillators). Sensitivity values were determined using Gate Monte Carlo simulations. Patient throughput times (including CT and scout scan, patient positioning on bed and transfer) were recorded for 1 day on a Siemens Vision 600 PET. These timing values were then used to estimate the expected patient throughput (assuming an equal patient radiotracer injected activity to patients and considering differences in system sensitivity and time-of-flight information) for WT-TB-PET, SAFOV and LAFOV PET.
RESULTS: The WT-TB-PET is composed of two flat panels; each is 70 cm wide and 106 cm high, with a 50-cm gap between both panels. These design dimensions were justified by the patient sizes measured from the 40 random PET-CT scans. Each panel consists of 14 × 20 monolithic BGO detector blocks that are 50 × 50 × 16 mm in size and are coupled to a readout with 6 × 6 mm SiPMs arrays. For the WT-TB-PET, the detector surface is reduced by a factor of 1.9 and the scintillator volume by a factor of 2.2 compared to LAFOV PET systems, while demonstrating comparable sensitivity and much better uniform spatial resolution (< 2 mm in all directions over the FOV). The estimated component cost for the WT-TB-PET is 3.3 × lower than that of a 106 cm LAFOV system and only 20% higher than the PET component costs of a SAFOV. The estimated maximum number of patients scanned on a standard 8-h working day increases from 28 (for SAFOV) to 53-60 (for LAFOV in limited/full acceptance) to 87 (for the WT-TB-PET). By scanning faster (more patients), the amount of ordered activity per patient can be reduced drastically: the WT-TB-PET requires 66% less ordered activity per patient than a SAFOV.
CONCLUSIONS: We propose a monolithic BGO or LYSO-based WT-TB-PET system with DOI measurements that departs from the classical patient positioning on a table and allows patients to stand upright between two flat panels. The WT-TB-PET system provides a solution to achieve a much lower cost TB-PET approaching the cost of a SAFOV system. High patient throughput is increased by fast patient positioning between two vertical flat panel detectors of high sensitivity. High spatial resolution (< 2 mm) uniform over the FOV is obtained by using DOI-capable monolithic scintillators.
Disciplines :
Radiology, nuclear medicine & imaging
Author, co-author :
Vandenberghe, Stefaan ; Medical Image and Signal Processing, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium. Stefaan.Vandenberghe@ugent.be
Muller, Florence M; Medical Image and Signal Processing, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium
Withofs, Nadia ; Centre Hospitalier Universitaire de Liège - CHU > > Service médical de médecine nucléaire et imagerie onco
Dadgar, Meysam; Medical Image and Signal Processing, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium
Maebe, Jens; Medical Image and Signal Processing, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium
Vervenne, Boris; Medical Image and Signal Processing, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium
Akl, Maya Abi; Medical Image and Signal Processing, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium
Xue, Song; Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
Shi, Kuangyu; Division of Nuclear Medicine and Oncological Imaging, Department of Medical Physics, CHU of Liege, Quartier Hôpital, Avenue de Hôpital, 1, 4000, Liège 1, Belgium
Sportelli, Giancarlo; Dipartimento Di Fisica "E. Fermi", Università Di Pisa, Italy and with the Instituto Nazionale Di Fisica Nucleare, Sezione Di Pisa, 56127, Pisa, Italy
Belcari, Nicola; Dipartimento Di Fisica "E. Fermi", Università Di Pisa, Italy and with the Instituto Nazionale Di Fisica Nucleare, Sezione Di Pisa, 56127, Pisa, Italy
Hustinx, Roland ; Centre Hospitalier Universitaire de Liège - CHU > > Service médical de médecine nucléaire et imagerie onco
Vanhove, Christian; Medical Image and Signal Processing, Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium
Karp, Joel S; Physics and Instrumentation, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
Walk-through flat panel total-body PET: a patient-centered design for high throughput imaging at lower cost using DOI-capable high-resolution monolithic detectors.
Publication date :
19 July 2023
Journal title :
European Journal of Nuclear Medicine and Molecular Imaging
ISSN :
1619-7070
eISSN :
1619-7089
Publisher :
Springer Science and Business Media Deutschland GmbH, Germany
Different total-body (TB) PET systems have been developed during the last years [] that was initiated through an NIH grant forming the EXPLORER consortium with UC Davis and UPenn. This resulted in development of a research scanner, the PennPET Explorer at UPENN with axial FOV ranging from 64 to 142 cm [, ] and a commercial product by United Imaging, the uEXPLORER with axial FOV of 194 cm []. A second commercial product was released soon after by Siemens, the Vision Quadra with axial FOV of 106 cm []. These TB-PET systems have now been installed in a reasonable number (> 25) of large centers in Europe, Asia, Australia, and the USA (mostly in academic sites of which some are supported by grant money). The acquisition and installation of most of these TB-PET scanners have at least partially been funded by grant money. This shows the large research potential of such long axial field-of-view (LAFOV) PET systems (e.g., studies on low radiation–dose imaging, TB dynamic imaging, new radiotracer development, delayed imaging, and brain–body interactions) [–]. For clinical routine imaging in more standard nuclear medicine (NM) centers (or for academic (research) centers with limited access to large grants), the high acquisition and service costs are, however, an obstacle as it is very hard to convince hospitals that these costs will be compensated (balanced) by an increased income for the NM department. These systems have about four to eight times the number of detectors of a standard PET-CT, which leads to an increase in system cost for the PET roughly linearly correlated with the increase in detectors []. At the time of writing, the sales price of a standard axial field-of-view (SAFOV) PET-CT is about 2–3 MEuro, resulting in a cost of about 8–12 MEuro for TB-PET scanners with 1–2 m LAFOVs.
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