Meet Phannie, NIST's Standard 'Phantom' for Calibrating MRI Machines

Magnetic resonance imaging (MRI)--a widely used medical tool that relies on magnetic fields and radio waves to visualize the body's internal structures, especially soft tissues--may soon become even more useful.

Phannie is the first “phantom” for calibrating magnetic resonance imaging (MRI) machines that is traceable to standardized values. The plastic sphere is about the size of a person’s head and filled with 100 smaller spheres used as contrast-enhancing agents and measurement reference markers. NIST researchers in Boulder, Colo., built Phannie and tested it on an MRI scanner at the University of Colorado Brain Imaging Center.

The National Institute of Standards and Technology (NIST) has unveiled the first “phantom” for calibrating MRI machines that is traceable to standardized values. The prototype, named Phannie, was developed in collaboration with the standards committee of the International Society for Magnetic Resonance in Medicine (ISMRM).

Traceable MRI calibrations are expected to enable accurate, quantitative measurements of tumors and other disease markers that can be reproduced across many different patients, scanners and clinics over time—and potentially reduce medical costs.

Displayed at the annual ISMRM meeting this past week,* the NIST phantom is a plastic sphere about the size of a person’s head, filled with water-bathed grids of 100 small plastic spheres containing various salt solutions that become magnetized in a magnetic field. By making MRI scans of Phannie, users can evaluate the image contrast, resolution, and accuracy of distance and volume measurements. A machine’s performance can be compared to standards, to other MRI machines, and to itself over time.

source: NIST

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