Are x-rays the ultimate? Proton (heavy ion) radiography in neurologic diagnosis

Radiations other than those of the electromagnetic spectrum or of sound may be used for neurologic diagnosis. These consist of beams of sub-atomic particles, particularly of protons and other heavy ions. With these beams radiographs of unusually high contrast are obtained for the visualization and differentiation of the soft body tissues at very low doses (down to approximately two orders of magnitude less than with x-rays). The method is practical for use in hospitals and has potential for screening purposes. The properties of these and other sub-atomic particles are reviewed for their diagnostic and basic research potential.