The introductory physics classroom has long educated students about the properties of the atom and the nucleus. But absent from these lessons has been an informed discussion of magnetic resonance imaging (MRI) and its parent science nuclear magnetic resonance (NMR). Physics teachers should not miss the opportunity to instruct upon this highly relevant application of modern physics, especially with so many of our students planning to pursue a career in medicine. This article provides an overview of the physics of MRI and gives advice on how physics teachers can introduce this topic. Also included are some demonstration activities and a discussion of a desktop MRI apparatus that may be used by students in the lab or as a demo.

Topics
General relativity, Electromagnetic coils, Nuclear magnetic resonance, Magnetic resonance imaging, Stereoscopy, Atomic properties, Gyromagnetic ratio, Educational aids, Teaching, Careers and professions
1.
For example, this topic is covered on the MCAT exam, especially the resonance of hydrogen. For example, see
Kaplan’s
 
MCAT Organic Chemistry Review
,
2018-19
(
Simon & Schuster, Inc.
).
Google Scholar
 
2.
These are the only two directions that hydrogen nuclei can assume since they retain energy in two discrete quantum states and thus have only two possible energies.
3.
The authors strongly recommend
Catherine
Westbrook
 and
Carolyn
Kaut
 ,
MRI in Practice
(
Blackwell Scientific Publishers
,
1993
). This book is an excellent source with great figures. Also, see
Google Scholar
 
Hans H.
 
Schild
,
MRI Made Easy: (… Well Almost)
(
Berlex Laboratories
,
1999
), which is an easy read, and we also found helpful.
Google Scholar
 
4.
Readers might notice that there is disagreement between the units of our gyromagnetic ratios and the units for γ. We have elected to express the ratios in Hz (by dividing them by 2π). In practice, rad/s is not what you put into your machine. Just like your car radio, we work in hertz, not radians/second.
5.
There has been an easy, yet innovative experiment on teaching magnetic resonance:
Sytil
 
Murphy
,
Dyan L.
 
Jones
,
Josh
 
Gross
, and
Dean
 
Zollman
, “
Apparatus for investigating resonance with application to magnetic resonance imaging
,”
Am J. Phys.
 
83
,
942
(
Nov.
 
2015
). In this paper they use a set of compasses in a gradient field (produced by a bar magnet), and each compass resonates at a different frequency.
https://doi.org/10.1119/1.4928177
Google Scholar
Crossref
Search ADS
 
6.
The award-winning Dr. Paul Callaghan created a series of 10 videos in which he explains the basics of MRI and how to use the Terranova. In the series he also dissects the device into its three coils. See the first of these here: https://www.youtube.com/watch?v=7aRKAXD4dAg.
8.
For a good talk on medical applications with regards to diagnosing and treating brain tumors, see
Dr. Duma’s
 “
Fighting Glioblastoma
.” TEDx video: https://www.youtube.com/watch?v=hErXkeIadsY.
9.
Special thanks to Dr. Usha Sinha, Director of Medical Physics and Physics Department Chair, at San Diego State University.
© 2018 American Association of Physics Teachers.
2018
American Association of Physics Teachers
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