APS March Meeting 2017
Volume 62, Number 4
Monday–Friday, March 13–17, 2017;
New Orleans, Louisiana
Session L29: FIAP Plenary: Physics that Changed the World
11:15 AM–2:15 PM,
Wednesday, March 15, 2017
Room: 292
Sponsoring
Unit:
FIAP
Chair: Eli Yablonovitch, University of California, Berkeley
Abstract ID: BAPS.2017.MAR.L29.3
Abstract: L29.00003 : Magnetic Resonance Medical Imaging (MRI)--from the inside
12:27 PM–1:03 PM
Preview Abstract
View Presentation
Abstract
Author:
Paul Bottomley
(Johns Hopkins University, Division of MR Research, Dept of Radiology)
There
are about 36,000 magnetic resonance imaging (MRI) scanners in the world,
with annual sales of \textasciitilde 2500. In the USA about 34 million MRI
studies are done annually, and 60-70{\%} of all scanners operate at 1.5
Tesla (T). In 1982 there were none. How MRI got to be--and how it got to1.5T
is the subject of this talk. Its an insider's view--mine--as a physics PhD
student at Nottingham University when MRI (almost) began, through to the
invention of the 1.5T clinical MRI scanner at GE's research center in
Schenectady NY.Before 1977 all MRI was done on laboratory nuclear magnetic
resonance instruments used for analyzing small specimens via chemical shift
spectroscopy (MRS). It began with Lauterbur's 1973 observation that turning
up the spectrometer's linear gradient magnetic field, generated a spectrum
that was a 1D projection of the sample in the direction of the gradient.
What followed in the 70's was the development of 3 key methods of 3D spatial
localization that remain fundamental to MRI today.As the 1980's began, the
once unimaginable prospect of upscaling from 2cm test-tubes to human
body-sized magnets, gradient and RF transmit/receive systems, was well
underway, evolving from arm-sized, to whole-body electromagnet-based systems
operating at \textless 0.2T. I moved to Johns Hopkins University to apply
MRI methods to localized MRS and study cardiac metabolism, and then to GE to
build a whole-body MRS machine. The largest uniform magnet possible--then, a
1.5T superconducting system--was required. Body MRI was first thought
impossible above 0.35T due to RF penetration, detector coil and
signal-to-noise ratio (SNR) issues. When GE finally did take on MRI, their
plan was to drop the field to \textasciitilde 0.3T. We opted to make MRI
work at 1.5T instead. The result was a scanner that could study both anatomy
and metabolism with a SNR way beyond its lower field rivals. MRI's success
truly reflects the team efforts of many: from the NMR physics to the
engineering of magnets, gradient and RF systems.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2017.MAR.L29.3