A Short History of the
Magnetic Resonance Imaging (MRI) Nikola
Tesla discovered the Rotating Magnetic Field in 1882 in Budapest, Hungary.
This was a fundamental discovery in physics. In
1956, the "Tesla Unit" was proclaimed in the Rathaus of Munich, Germany by
the International Electro-technical Commission-Committee
of Action. All MRI machines are calibrated in "Tesla Units".
The strength of a magnetic field is measured in Tesla or Gauss Units.
The stronger the magnetic field, the stronger the amount of radio signals
which can be elicited from the body's atoms and therefore the higher the
quality of MRI images. 1 Tesla =
10,000 Gauss Low-Field MRI=
Under .2 Tesla (2,000 Gauss)
Mid-Field MRI= .2 to 0.6 Tesla (2,000 Gauss to 6,000 Gauss)
High-Field MRI= 1.0 to 1.5 Tesla (10,000 Gauss to 15,000
Gauss) In 1937, Columbia University Professor
Isidor I. Rabi working in the Pupin Physic Laboratory in Columbia
University, New York City, observed the quantum phenomenon dubbed nuclear
magnetic resonance (NMR). He recognized that the atomic nuclei show
their presence by absorbing or emitting radio waves when exposed to a
sufficiently strong magnetic field. Professor Isidor
I. Rabi received the Nobel Prize for his work. He is one of 28 Nobel
Laureates from the Pupin Physics Laboratory in New York City.
Raymond Damadian, a physician and experimenter working at Brooklyn's
Downstate Medical Center discovered that hydrogen signal in cancerous
tissue is different from that of healthy tissue because tumors contain
more water. More water means more hydrogen atoms. When the MRI
machine was switched off, the bath of radio waves from cancerous tissue
will linger longer then those from the healthy tissue.
In 1973, Paul Lauterbur, a chemist and an NMR pioneer at the State
University of New York, Stony Brook, produced the first NMR image.
Mike Goldsmith, one of the graduate students cobbled a wearable antenna
coil to monitor the hydrogen broadcast detected by the coil.
On July 3, 1977, nearly five hours after the start of the first MRI
test, the first human scan was made as the first MRI prototype.
How MRI works?
Magnetic Resonance Imaging is a medical diagnostic technique that creates
images of the human body using the principle of nuclear magnetic
resonance. It can generate thin-section images of any part of the
human body - from any angle and direction. MRI is possible to make
such a picture of the human body when the body is exposed to an
electromagnetic field.
MRI creates a strong magnetic field and the small
biological "magnets" in the human body consisting of protons located in
the nucleus of the hydrogen atom are magnetized. The proton possess
fundamental magnetic properties. First, MRI creates
a steady state of magnetism within the human body by placing the body in a
steady magnetic field. Second, the MRI stimulates the body with
radio waves to change the steady-state orientation of protons.
Third, the MRI machine stops the radio waves and registers the body's
electromagnetic transmission. Fourth, the transmitted signal are
used to construct internal images of the body by computerized axial
tomography. An MRI image is not a photograph.
It is actually a computerized map or image of radio signals emitted by the
human body. MRI is superior to CAT scan because CAT scan is using
ionizing radiation, MRI uses harmless radio waves. The only unusual
preparation is that all removable metallic objects must be left outside
the scanning room, including removable hearing aids, dentures and other
prosthetic devices. Credit cards can be damaged by the MRI because
magnetic codes can be affected by the MRI magnet.
Magnetic Resonance Imaging is a powerful diagnostic tool in the medical
imaging market place as the procedure of choice for the visualization of
soft tissue. The MRI industry is producing over 2,000 units per
year. The United States is represented with 40% of the world
marketing and production of MRI. There is an emerging consensus that
the MRI has a broad application in smaller hospital and clinics.
Neurologists are one of medical specialty that depend a great deal on
MRI for accurate diagnostic of the central nerve system. Other
medical specialty that rely upon the MRI technology include neurosurgeons,
orthopedic surgeons and chiropractors. MRI is useful in diagnosis of
"pinched nerves" in the spinal column, heart disease, multiple sclerosis
and other diseases of the central nerve system. The
use of MRI technology will increase in the United States and the world
because of the tremendous significance in modern medical diagnosis.
The Tesla Unit is a label on every MRI machine signifying the strength of
the MRI Magnetic Field. The stronger the magnetic field, the
better the image of the MRI. Tesla's name connected with MRI
technology will be more and more widely known around the world. |