Synthesized tissue‐equivalent dielectric phantoms using salt and polyvinylpyrrolidone solutions. Issue 1 (20th November 2017)

• Record Type: Journal Article
• Authors: Ianniello, Carlotta; de Zwart, Jacco A.; Duan, Qi; Deniz, Cem M.; Alon, Leeor; Lee, Jae‐Seung; Lattanzi, Riccardo; Brown, Ryan
• Is Part Of: Magnetic resonance in medicine. Volume 80:Issue 1(2018)
• Page Start: 413
• Page End: 419
• Publication Date: 2017-11-20
• Subjects: High‐field MRI -- MR phantoms -- tissue equivalent materials -- electrical conductivity -- relative permittivity; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.27005
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: To explore the use of polyvinylpyrrolidone (PVP) for simulated materials with tissue‐equivalent dielectric properties. Methods: PVP and salt were used to control, respectively, relative permittivity and electrical conductivity in a collection of 63 samples with a range of solute concentrations. Their dielectric properties were measured with a commercial probe and fitted to a 3D polynomial in order to establish an empirical recipe. The material's thermal properties and MR spectra were measured. Results: The empirical polynomial recipe (available athttps://www.amri.ninds.nih.gov/cgi-bin/phantomrecipe ) provides the PVP and salt concentrations required for dielectric materials with permittivity and electrical conductivity values between approximately 45 and 78, and 0.1 to 2 siemens per meter, respectively, from 50 MHz to 4.5 GHz. The second‐ (solute concentrations) and seventh‐ (frequency) order polynomial recipe provided less than 2.5% relative error between the measured and target properties. PVP side peaks in the spectra were minor and unaffected by temperature changes. Conclusion: PVP‐based phantoms are easy to prepare and nontoxic, and their semitransparency makes air bubbles easy to identify. The polymer can be used to create simulated material with a range of dielectric properties, negligible spectral side peaks, and long T2 relaxation time, which are favorable in many MR applications. Magn Reson Med 80:413–419, 2018. © 2017 International Society for Magnetic Resonance in Medicine.