Diagnostic imaging refers to a variety of non-invasive methods for identifying and monitoring diseases or injuries via the generation of images representing internal anatomic structures and organs of the patient's body.
Sound waves travel fastest through a solid material. The second fastest medium is a liquid, and the slowest medium is a gas, because sound waves travel by vibrating molecules in a medium. In solids,... Sound waves travel fastest through a solid material.
Sound travels at around 330 meters a second; electromagnetic waves, at around 300,000,000 meters per second, almost a million times faster. Nonetheless, as I said before, if somehow you could turn your eardrums into effectively an antenna, you could hear radio waves just fine.