Bone material analogues for PET/MRI phantoms.
Med Phys
; 47(5): 2161-2170, 2020 Jun.
Article
em En
| MEDLINE
| ID: mdl-32034945
ABSTRACT
PURPOSE:
To develop bone material analogues that can be used in construction of phantoms for simultaneous PET/MRI systems.METHODS:
Plaster was used as the basis for the bone material analogues tested in this study. It was mixed with varying concentrations of an iodinated CT contrast, a gadolinium-based MR contrast agent, and copper sulfate to modulate the attenuation properties and MRI properties (T1 and T2*). Attenuation was measured with CT and 68 Ge transmission scans, and MRI properties were measured with quantitative ultrashort echo time pulse sequences. A proof-of-concept skull was created by plaster casting.RESULTS:
Undoped plaster has a 511 keV attenuation coefficient (~0.14 cm-1 ) similar to cortical bone (0.10-0.15 cm-1 ), but slightly longer T1 (~500 ms) and T2* (~1.2 ms) MR parameters compared to bone (T1 ~ 300 ms, T2* ~ 0.4 ms). Doping with the iodinated agent resulted in increased attenuation with minimal perturbation to the MR parameters. Doping with a gadolinium chelate greatly reduced T1 and T2*, resulting in extremely short T1 values when the target T2* values were reached, while the attenuation coefficient was unchanged. Doping with copper sulfate was more selective for T2* shortening and achieved comparable T1 and T2* values to bone (after 1 week of drying), while the attenuation coefficient was unchanged.CONCLUSIONS:
Plaster doped with copper sulfate is a promising bone material analogue for a PET/MRI phantom, mimicking the MR properties (T1 and T2*) and 511 keV attenuation coefficient of human cortical bone.Palavras-chave
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Osso e Ossos
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Imageamento por Ressonância Magnética
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Imagens de Fantasmas
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Materiais Biomiméticos
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Tomografia por Emissão de Pósitrons
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Osso Cortical
Idioma:
En
Revista:
Med Phys
Ano de publicação:
2020
Tipo de documento:
Article