The Physics of an MRI Machine.
The Physics of an MRI Machine
There are many physical concepts used in a Magnetic Resonance Imaging, also known as MRI, machine. There are many physical concepts used when an MRI is taken of the body, such as; radio waves, resonance and pulse sequences, magnetic fields being produced and lastly, magnets.
Radio waves much stronger than the magnetic field of the Earth are sent through the body which causes the nuclei in the body to move to a different position. When the nuclei move back to the place they originated from, they send back radio waves that the scanner on the machine picks up and turns them into a picture.
Resonance is very common within multiple branches of physics, without resonance we wouldn’t have television, music or radio. Resonance is also one of the most unexplained phenomenons in physics; it causes glass to break with a high pitched voice, bridges to collapse and also earthquakes causing buildings to collapse. Within the MRI, nuclear magnetic resonance is used, this is when magnetic fields and radio waves cause the atoms in the body to give off tiny radio waves (Bellis). The explanation of Pulse sequences are defined in a basic way by the article “MRI Physics: pulse sequences” as ‘the pulse sequences define the manner in which the radiofrequency pulses, which generate the detectable signals, and magnetic field gradients, which provide the spatial encoding of the signals’ (Sharma). When the pulse sequences are used a sequence diagram is used to show how the sequences will occur during the MRI. There are many different sequences available; each used for creating certain images, the most commonly used is the spin echo sequence.
When magnetic fields are produced, it means an electron has moved along a wire creating a magnetic field around that electron. When the wire is in the form of a loop, or multiple loops in this...
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Cluett, Jonathan. "MRI: What is a MRI?." About.com, Orthopedics. New York Times Company, 15 Aug. 2011. Web. 5 June 2012. .
Sharma, Harish, and Jim Lagopoulos. "MRI physics: pulse sequences." Acta Neuropsychiatrica 22.2 (2010): 90. EBSCOhost. Web. 5 June 2012. .
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