A Window into Anatomy and Physiology

What is different about biomedical NMR The title of this section says it all As chemists, we are used to having rela- 

Let us examine some of these issues in more detail. 

Often the question is asked, Is NMR harmful There is a story told by Nobel Prize winner and Professor of Physics Edward Purcell of Harvard that about the time the university s cyclotron was being constructed, he wondered whether a person could sense the tipping and forced precession of proton spins in his or her own brain. The perfect opportunity arose just as the huge cyclotron magnets had been completed but before the vacuum chamber had been inserted into the magnet gap. He and a colleague constructed an rf coil in the gap one of them placed his head in the coil, while the other connected an oscillator and tuned it to the proton Larmor frequency. Purcell reports that neither physicist could tell when his brain passed in and out of resonance. That undoubtedly marks the first NMR experiment on human subjects, and no untoward 

As discussed above, NMR uses no ionizing radiation, so that particular element of risk to subjects is eliminated. Just as it is possible to damage a sample (and the probe ) by 

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