Bone material analogues for PET/MRI phantoms

Dharshan Chandramohan, Peng Cao, Misung Han, Hongyu An, John J. Sunderland, Paul E. Kinahan, Richard Laforest, Thomas A. Hope, Peder E.Z. Larson

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


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 68Ge 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.

Original languageEnglish
Pages (from-to)2161-2170
Number of pages10
JournalMedical physics
Issue number5
StatePublished - Jun 1 2020


  • attenuation correction
  • bone materials
  • doped plaster


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