What is the abbreviation for the radiographic procedure that produces a series of cross-sectional images?

The answer is MRI. The abbreviation stands for Magnetic Imaging Resonance.  The technique involves the use of powerful magnetic and radiowaves to induce nuclear spins in certain atoms of the object under study (mostly hydrogen in humans). As the nuclear spin decays (following the withdrawal of the powerful magnetic field), the atoms release radio waves hence their locations are read and interpreted by a computer into an image. This is done in cross-sections of the object until the whole image is rendered

The proton has a positive charge while the neutron has no charge they both make up the nucleus of the atom while the elections have a negative charge and surround the nucleus of the atom. the protons and electrons are used to calculate the atom's mass whereas the neutrons don't affect the mass