In this section...
In the lab...
History Timeline
Pathologies
Drawbacks
MRI
In the lab...
Magnetic Amount: The magnetic amount of a MRI machine is from 0.5 to 2 tesla.
Safety Precautions: Due to the use of magnets, all metal items are removed from the area. Credit cards and other types of bank cards are also removed since magnets will erase the magnetic encoding embedded in the cards. In addition, people with pacemakers, dental or orthopedic implants or any such metallic implants are prohibited to be near the scanner at all times. Although there have been no known side effects, pregnant women are generally preferred not to be scanned; the effects on the developing fetus are currently unknown.
Orientation of Patient: Depending on the injury and type of MRI scanner, patients lay face up or down on a suspended bed. In a cardiac MRI, patients are typically placed in a supine manner. The patient feels nothing during the scan but may feel somewhat claustrophobic due to the limited amount of space. The patient must also lie still since movements may distort the images produced.
Length of Scan: MRI scanning is a long process requiring a patient to lie still anywhere from half an hour to an hour and a half.
History Timeline
1941 - Yevgeni K. Zavoisky discovers the electron spin resonance phenomenon. However, his attempts to detect and measure magnetic resonance fail.
1946 - Felix Bloch and Edward Purcell work independently and create the first instruments that could perform magnetic resonance imaging with bulk material.
1970 - Raymond Damadian demonstrates that the time taken by a proton to release energy differs between abnormal and normal tissues. In other words, the relaxation period, or the time it takes a proton to release its energy, would determine the normality of the tissues being studied.
1973 - Up until this point, the image produced lacks spatial information. The image is only one dimensional. Paul Lauterbur discovers a new imaging technique that was able to produce two-dimensional images. He coins his technique Zeugmatography.
1975 - Unlike Lauterbur’s technique, Richard Ernst discovers a new technique that is the basis of today’s magnetic resonance imaging scanners. Richard Ernst also used the Fourier transformation.
1977 - The first MRI images are presented. Peter Mansfield and Andrew Maudsley show a cross section through a finger. Also during this year Raymond Damadian founds the FONAR corporation that manufactures MRI scanners and receives FDA approval in 1981.
