In nMRIs the strong magnetic field plus the radio wave aligns protons. 1). Which protons? Just the proton ions (actually H3O+) from water; or protons in all molecules that contain hydrogen atoms such as water, fats, carbohydrates, proteins? 2). The relaxation phase does what? As the protons go back to equilibrium there is an emission of radio waves? 3). Isn't that a form of γ radiation? Doesn't it have inherent risks? HELP!