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Optimizing reconstruction parameters for quantitative (124)I-PET in the presence of therapeutic doses of (131)I
BACKGROUND: The goal of this work was to determine the quantitative accuracy and optimal reconstruction parameters for (124)I-PET imaging in the presence of therapeutic levels of (131)I. In this effort, images were acquired on a GE D710 PET/CT scanner using a NEMA IEC phantom with spheres containing...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer International Publishing
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8273044/ https://www.ncbi.nlm.nih.gov/pubmed/34250566 http://dx.doi.org/10.1186/s40658-021-00398-z |
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author | Fanchon, Louise M. Beattie, Bradley J. Pentlow, Keith Larson, Steven M. Humm, John L. |
author_facet | Fanchon, Louise M. Beattie, Bradley J. Pentlow, Keith Larson, Steven M. Humm, John L. |
author_sort | Fanchon, Louise M. |
collection | PubMed |
description | BACKGROUND: The goal of this work was to determine the quantitative accuracy and optimal reconstruction parameters for (124)I-PET imaging in the presence of therapeutic levels of (131)I. In this effort, images were acquired on a GE D710 PET/CT scanner using a NEMA IEC phantom with spheres containing (124)I and increasing amounts of (131)I activity in the background. At each activity level, two scans were acquired, one with the phantom centered in the field of view (FOV) and one 11.2 cm off-center. Reconstructions used an ordered subset expectation maximization algorithm with up to 100 iterations of 16 subsets, with and without time-of-flight (TOF) information. Results were evaluated visually and by comparing the (124)I activity relative to the scan performed in the absence of (131)I. RESULTS: (131)I within the FOV added to the randoms rate, to dead time, and to pile-up within the detectors. Using our standard clinical reconstruction parameters, the image quality and quantitative accuracy suffered at (131)I activities above 1.4 GBq. Convergence rates slowed progressively in the presence of increasing amounts of (131)I for both TOF and nonTOF reconstructions. TOF reconstructions converged more quickly than nonTOF but often towards erroneous concentrations. Iterating nonTOF reconstructions to convergence produced quantitatively accurate images except for the off-center phantom at the very highest level of background (131)I tested. CONCLUSIONS: This study shows that quantitative PET is feasible in the presence of large amounts of (131)I. The high randoms fractions resulted in slow reconstruction convergence and negatively impacted TOF corrections and/or the accuracy of TOF information. Therefore, increased iterations and nonTOF reconstructions are recommended. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40658-021-00398-z. |
format | Online Article Text |
id | pubmed-8273044 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Springer International Publishing |
record_format | MEDLINE/PubMed |
spelling | pubmed-82730442021-07-20 Optimizing reconstruction parameters for quantitative (124)I-PET in the presence of therapeutic doses of (131)I Fanchon, Louise M. Beattie, Bradley J. Pentlow, Keith Larson, Steven M. Humm, John L. EJNMMI Phys Original Research BACKGROUND: The goal of this work was to determine the quantitative accuracy and optimal reconstruction parameters for (124)I-PET imaging in the presence of therapeutic levels of (131)I. In this effort, images were acquired on a GE D710 PET/CT scanner using a NEMA IEC phantom with spheres containing (124)I and increasing amounts of (131)I activity in the background. At each activity level, two scans were acquired, one with the phantom centered in the field of view (FOV) and one 11.2 cm off-center. Reconstructions used an ordered subset expectation maximization algorithm with up to 100 iterations of 16 subsets, with and without time-of-flight (TOF) information. Results were evaluated visually and by comparing the (124)I activity relative to the scan performed in the absence of (131)I. RESULTS: (131)I within the FOV added to the randoms rate, to dead time, and to pile-up within the detectors. Using our standard clinical reconstruction parameters, the image quality and quantitative accuracy suffered at (131)I activities above 1.4 GBq. Convergence rates slowed progressively in the presence of increasing amounts of (131)I for both TOF and nonTOF reconstructions. TOF reconstructions converged more quickly than nonTOF but often towards erroneous concentrations. Iterating nonTOF reconstructions to convergence produced quantitatively accurate images except for the off-center phantom at the very highest level of background (131)I tested. CONCLUSIONS: This study shows that quantitative PET is feasible in the presence of large amounts of (131)I. The high randoms fractions resulted in slow reconstruction convergence and negatively impacted TOF corrections and/or the accuracy of TOF information. Therefore, increased iterations and nonTOF reconstructions are recommended. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40658-021-00398-z. Springer International Publishing 2021-07-12 /pmc/articles/PMC8273044/ /pubmed/34250566 http://dx.doi.org/10.1186/s40658-021-00398-z Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Original Research Fanchon, Louise M. Beattie, Bradley J. Pentlow, Keith Larson, Steven M. Humm, John L. Optimizing reconstruction parameters for quantitative (124)I-PET in the presence of therapeutic doses of (131)I |
title | Optimizing reconstruction parameters for quantitative (124)I-PET in the presence of therapeutic doses of (131)I |
title_full | Optimizing reconstruction parameters for quantitative (124)I-PET in the presence of therapeutic doses of (131)I |
title_fullStr | Optimizing reconstruction parameters for quantitative (124)I-PET in the presence of therapeutic doses of (131)I |
title_full_unstemmed | Optimizing reconstruction parameters for quantitative (124)I-PET in the presence of therapeutic doses of (131)I |
title_short | Optimizing reconstruction parameters for quantitative (124)I-PET in the presence of therapeutic doses of (131)I |
title_sort | optimizing reconstruction parameters for quantitative (124)i-pet in the presence of therapeutic doses of (131)i |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8273044/ https://www.ncbi.nlm.nih.gov/pubmed/34250566 http://dx.doi.org/10.1186/s40658-021-00398-z |
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