Improving the CT (140 kVp) to PET (511 keV) conversion in PET/MR hardware component attenuation correction.
Hounsfield unit (HU)
PET/MR
attenuation correction (AC)
linear attenuation coefficient (LAC)
Journal
Medical physics
ISSN: 2473-4209
Titre abrégé: Med Phys
Pays: United States
ID NLM: 0425746
Informations de publication
Date de publication:
Jun 2020
Jun 2020
Historique:
received:
22
07
2019
revised:
10
02
2020
accepted:
10
02
2020
pubmed:
14
2
2020
medline:
2
3
2021
entrez:
14
2
2020
Statut:
ppublish
Résumé
Today, attenuation correction (AC) of positron emission tomography/magnetic resonance (PET/MR) hardware components is performed by using an established method from PET/CT hybrid imaging. As shown in previous studies, the established mathematical conversion from computed tomography (CT) to PET attenuation coefficients may, however, lead to incorrect results in PET quantification when applied to AC of hardware components in PET/MR. The purpose of this study is to systematically investigate the attenuating properties of various materials and electronic components frequently used in the context of PET/MR hybrid imaging. The study, thus, aims at improving hardware component attenuation correction in PET/MR. Overall, 38 different material samples were collected; a modular phantom was used to for CT, PET, and PET/MR scanning of all samples. Computed tomography-scans were acquired with a tube voltage of 140 kVp to determine Hounsfield Units (HU). PET transmission scans were performed with 511 keV to determine linear attenuation coefficients (LAC) of all materials. The attenuation coefficients were plotted to obtain a HU to LAC correlation graph, which was then compared to two established conversions from literature. Hardware attenuation maps of the different materials were created and applied to PET data reconstruction following a phantom validation experiment. From these measurements, PET difference maps were calculated to validate and compare all three conversion methods. For each material, the HU and corresponding LAC could be determined and a bi-linear HU to LAC conversion graph was derived. The corresponding equation was An optimized method for the conversion of CT to PET attenuation coefficients has been derived by systematic measurement of 38 different materials. In contrast to established methods, the new conversion also considers highly attenuating materials, thus improving attenuation correction of hardware components in PET/MR hybrid imaging.
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
2116-2127Informations de copyright
© 2020 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.
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