MAGNETIC RESONANCE IMAGING THEORY PHYSICS
Assignment Questions
You have been introduced to the concept of the magnetic moment of certain nuclei. Describe, with examples, what is meant by magnetic moment. Under what circumstances does a nucleus have a magnetic moment? (1 paragraph each)
For a hydrogen nucleus, what is the energy difference between the parallel and antiparallel states when placed in a 1.5 T magnetic field? What are the units of energy measured in? If one were to double the magnetic field strength, what happens to the energy difference? Given that the frequency of an x-ray is 2 x 1019 Hz, calculate the energy of the photon. Comment on the biological significance of the relative energies used in MRI and CT
Calculate the resonance frequencies of the following nuclides at 3T and 7T: 1H, 2H, 19F, 129Xe, and 31P.
The rf coil acquires signal in the laboratory frame. Why? What is “demodulation” and how does it relate to the rotating frame?