Diathermy is a deep tissue heat treatment. High frequency current is generated through a coil to produce a rapidly reversing magnetic field. The coil is wound inside an applicator and is positioned directly over or next to the area to be treated. The rapidly reversing magnetic field induces circulating currents and electric fields into the body tissues, producing heat in the tissues. This heat is used to reduce pain, relieve muscle spasm, decrease soft-tissue contractors, resolve inflammation and promote healing.