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PET performance evaluation of the small-animal Hyperion II(D) PET/MRI insert based on the NEMA NU-4 standard
The Hyperion II(D) PET insert is the first scanner using fully digital silicon photomultipliers for simultaneous PET/MR imaging of small animals up to rabbit size. In this work, we evaluate the PET performance based on the National Eletrical Manufacturers Association (NEMA) NU 4-2008 standard, whose...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
IOP Publishing
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6329443/ https://www.ncbi.nlm.nih.gov/pubmed/30675384 http://dx.doi.org/10.1088/2057-1976/aae6c2 |
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author | Hallen, Patrick Schug, David Weissler, Bjoern Gebhardt, Pierre Salomon, André Kiessling, Fabian Schulz, Volkmar |
author_facet | Hallen, Patrick Schug, David Weissler, Bjoern Gebhardt, Pierre Salomon, André Kiessling, Fabian Schulz, Volkmar |
author_sort | Hallen, Patrick |
collection | PubMed |
description | The Hyperion II(D) PET insert is the first scanner using fully digital silicon photomultipliers for simultaneous PET/MR imaging of small animals up to rabbit size. In this work, we evaluate the PET performance based on the National Eletrical Manufacturers Association (NEMA) NU 4-2008 standard, whose standardized measurement protocols allow comparison of different small-animal PET scanners. The Hyperion II(D) small-animal PET/MR insert comprises three rings of 20 detector stacks with pixelated scintillator arrays with a crystal pitch of 1 mm, read out with digital silicon photomultipliers. The scanner has a large ring diameter of 209.6 mm and an axial field of view of 96.7 mm. We evaluated the spatial resolution, energy resolution, time resolution and sensitivity by scanning a (22)Na point source. The count rates and scatter fractions were measured for a wide range of (18)F activity inside a mouse-sized scatter phantom. We evaluated the image quality using the mouse-sized image quality phantom specified in the NEMA NU4 standard, filled with (18)F. Additionally, we verified the in-vivo imaging capabilities by performing a simultaneous PET/MRI scan of a mouse injected with (18)F-FDG. We processed all measurement data with an energy window of 250 keV to 625 keV and a coincidence time window of 2 ns. The filtered-backprojection reconstruction of the point source has a full width at half maximum (FWHM) of 1.7 mm near the isocenter and degrades to 2.5 mm at a radial distance of 50 mm. The scanner’s average energy resolution is 12.7% (ΔE/E FWHM) and the coincidence resolution time is 609 ps. The peak absolute sensitivity is 4.0% and the true and noise-equivalent count rates reach their peak at an activity of 46 MBq with 483 kcps and 407 kcps, respectively, with a scatter fraction of 13%. The iterative reconstruction of the image quality phantom has a uniformity of 3.7%, and recovery coefficients from 0.29, 0.91 and 0.94 for rod diameters of 1 mm, 3 mm and 5 mm, respectively. After application of scatter and attenuation corrections, the air- and water-filled cold regions have spill-over ratios of 6.3% and 5.4%, respectively. The Hyperion II(D) PET/MR insert provides state-of-the-art PET performance while enabling simultaneous PET/MRI acquisition of small animals up to rabbit size. |
format | Online Article Text |
id | pubmed-6329443 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | IOP Publishing |
record_format | MEDLINE/PubMed |
spelling | pubmed-63294432019-01-21 PET performance evaluation of the small-animal Hyperion II(D) PET/MRI insert based on the NEMA NU-4 standard Hallen, Patrick Schug, David Weissler, Bjoern Gebhardt, Pierre Salomon, André Kiessling, Fabian Schulz, Volkmar Biomed Phys Eng Express Paper The Hyperion II(D) PET insert is the first scanner using fully digital silicon photomultipliers for simultaneous PET/MR imaging of small animals up to rabbit size. In this work, we evaluate the PET performance based on the National Eletrical Manufacturers Association (NEMA) NU 4-2008 standard, whose standardized measurement protocols allow comparison of different small-animal PET scanners. The Hyperion II(D) small-animal PET/MR insert comprises three rings of 20 detector stacks with pixelated scintillator arrays with a crystal pitch of 1 mm, read out with digital silicon photomultipliers. The scanner has a large ring diameter of 209.6 mm and an axial field of view of 96.7 mm. We evaluated the spatial resolution, energy resolution, time resolution and sensitivity by scanning a (22)Na point source. The count rates and scatter fractions were measured for a wide range of (18)F activity inside a mouse-sized scatter phantom. We evaluated the image quality using the mouse-sized image quality phantom specified in the NEMA NU4 standard, filled with (18)F. Additionally, we verified the in-vivo imaging capabilities by performing a simultaneous PET/MRI scan of a mouse injected with (18)F-FDG. We processed all measurement data with an energy window of 250 keV to 625 keV and a coincidence time window of 2 ns. The filtered-backprojection reconstruction of the point source has a full width at half maximum (FWHM) of 1.7 mm near the isocenter and degrades to 2.5 mm at a radial distance of 50 mm. The scanner’s average energy resolution is 12.7% (ΔE/E FWHM) and the coincidence resolution time is 609 ps. The peak absolute sensitivity is 4.0% and the true and noise-equivalent count rates reach their peak at an activity of 46 MBq with 483 kcps and 407 kcps, respectively, with a scatter fraction of 13%. The iterative reconstruction of the image quality phantom has a uniformity of 3.7%, and recovery coefficients from 0.29, 0.91 and 0.94 for rod diameters of 1 mm, 3 mm and 5 mm, respectively. After application of scatter and attenuation corrections, the air- and water-filled cold regions have spill-over ratios of 6.3% and 5.4%, respectively. The Hyperion II(D) PET/MR insert provides state-of-the-art PET performance while enabling simultaneous PET/MRI acquisition of small animals up to rabbit size. IOP Publishing 2018-11 2018-10-24 /pmc/articles/PMC6329443/ /pubmed/30675384 http://dx.doi.org/10.1088/2057-1976/aae6c2 Text en © 2018 IOP Publishing Ltd http://creativecommons.org/licenses/by/3.0/ Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence (http://creativecommons.org/licenses/by/3.0/) . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
spellingShingle | Paper Hallen, Patrick Schug, David Weissler, Bjoern Gebhardt, Pierre Salomon, André Kiessling, Fabian Schulz, Volkmar PET performance evaluation of the small-animal Hyperion II(D) PET/MRI insert based on the NEMA NU-4 standard |
title | PET performance evaluation of the small-animal Hyperion II(D) PET/MRI insert based on the NEMA NU-4 standard |
title_full | PET performance evaluation of the small-animal Hyperion II(D) PET/MRI insert based on the NEMA NU-4 standard |
title_fullStr | PET performance evaluation of the small-animal Hyperion II(D) PET/MRI insert based on the NEMA NU-4 standard |
title_full_unstemmed | PET performance evaluation of the small-animal Hyperion II(D) PET/MRI insert based on the NEMA NU-4 standard |
title_short | PET performance evaluation of the small-animal Hyperion II(D) PET/MRI insert based on the NEMA NU-4 standard |
title_sort | pet performance evaluation of the small-animal hyperion ii(d) pet/mri insert based on the nema nu-4 standard |
topic | Paper |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6329443/ https://www.ncbi.nlm.nih.gov/pubmed/30675384 http://dx.doi.org/10.1088/2057-1976/aae6c2 |
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