Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system.

Positron Emission Mammography (PEM) is a valuable molecular imaging technique for breast studies using pharmaceuticals labeled with positron emitters and dual-panel detectors. PEM scanners normally use large scintillation crystals coupled to sensitive photodetectors. Multiple interactions of the 511...

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Main Authors: Rahal Saaidi, Mercedes Rodríguez-Villafuerte, Héctor Alva-Sánchez, Arnulfo Martínez-Dávalos
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2024-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0297829
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author Rahal Saaidi
Mercedes Rodríguez-Villafuerte
Héctor Alva-Sánchez
Arnulfo Martínez-Dávalos
author_facet Rahal Saaidi
Mercedes Rodríguez-Villafuerte
Héctor Alva-Sánchez
Arnulfo Martínez-Dávalos
author_sort Rahal Saaidi
collection DOAJ
description Positron Emission Mammography (PEM) is a valuable molecular imaging technique for breast studies using pharmaceuticals labeled with positron emitters and dual-panel detectors. PEM scanners normally use large scintillation crystals coupled to sensitive photodetectors. Multiple interactions of the 511 keV annihilation photons in the crystals can result in event mispositioning leading to a negative impact in radiopharmaceutical uptake quantification. In this work, we report the study of crystal scatter effects of a large-area dual-panel PEM system designed with either monolithic or pixelated lutetium yttrium orthosilicate (LYSO) crystals using the Monte Carlo simulation platform GATE. The results show that only a relatively small fraction of coincidences (~20%) arise from events where both coincidence photons undergo single interactions (mostly through photoelectric absorption) in the crystals. Most of the coincidences are events where at least one of the annihilation photons undergoes a chain of Compton scatterings: approximately 79% end up in photoelectric absorption while the rest (<1%) escape the detector. Mean positioning errors, calculated as the distance between first hit and energy weighted (assigned) positions of interaction, were 1.70 mm and 1.92 mm for the monolithic and pixelated crystals, respectively. Reconstructed spatial resolution quantification with a miniDerenzo phantom and a list mode iterative reconstruction algorithm shows that, for both crystal types, 2 mm diameter hot rods were resolved, indicating a relatively small effect in spatial resolution. A drastic reduction in peak-to-valley ratios for the same hot-rod diameters was observed, up to a factor of 14 for the monolithic crystals and 7.5 for the pixelated ones.
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spelling doaj.art-4572c07396f14a63b84b365618f9605e2024-03-11T05:32:07ZengPublic Library of Science (PLoS)PLoS ONE1932-62032024-01-01193e029782910.1371/journal.pone.0297829Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system.Rahal SaaidiMercedes Rodríguez-VillafuerteHéctor Alva-SánchezArnulfo Martínez-DávalosPositron Emission Mammography (PEM) is a valuable molecular imaging technique for breast studies using pharmaceuticals labeled with positron emitters and dual-panel detectors. PEM scanners normally use large scintillation crystals coupled to sensitive photodetectors. Multiple interactions of the 511 keV annihilation photons in the crystals can result in event mispositioning leading to a negative impact in radiopharmaceutical uptake quantification. In this work, we report the study of crystal scatter effects of a large-area dual-panel PEM system designed with either monolithic or pixelated lutetium yttrium orthosilicate (LYSO) crystals using the Monte Carlo simulation platform GATE. The results show that only a relatively small fraction of coincidences (~20%) arise from events where both coincidence photons undergo single interactions (mostly through photoelectric absorption) in the crystals. Most of the coincidences are events where at least one of the annihilation photons undergoes a chain of Compton scatterings: approximately 79% end up in photoelectric absorption while the rest (<1%) escape the detector. Mean positioning errors, calculated as the distance between first hit and energy weighted (assigned) positions of interaction, were 1.70 mm and 1.92 mm for the monolithic and pixelated crystals, respectively. Reconstructed spatial resolution quantification with a miniDerenzo phantom and a list mode iterative reconstruction algorithm shows that, for both crystal types, 2 mm diameter hot rods were resolved, indicating a relatively small effect in spatial resolution. A drastic reduction in peak-to-valley ratios for the same hot-rod diameters was observed, up to a factor of 14 for the monolithic crystals and 7.5 for the pixelated ones.https://doi.org/10.1371/journal.pone.0297829
spellingShingle Rahal Saaidi
Mercedes Rodríguez-Villafuerte
Héctor Alva-Sánchez
Arnulfo Martínez-Dávalos
Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system.
PLoS ONE
title Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system.
title_full Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system.
title_fullStr Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system.
title_full_unstemmed Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system.
title_short Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system.
title_sort crystal scatter effects in a large area dual panel positron emission mammography system
url https://doi.org/10.1371/journal.pone.0297829
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