RT Book, Section A1 Post, Robert A1 Nolan Jr., Thomas P. A2 Bellew, James W. A2 Michlovitz, Susan L. A2 Nolan Jr., Thomas P. SR Print(0) ID 1180666938 T1 Electromagnetic Waves—Laser, Diathermy, and Pulsed Electromagnetic Fields T2 Modalities for Therapeutic Intervention, 6e YR 2016 FD 2016 PB McGraw-Hill Education PP New York, NY SN 9780803645639 LK fadavispt.mhmedical.com/content.aspx?aid=1180666938 RD 2024/04/23 AB The understanding of electromagnetic theory in the 19th century led to the development of the wireless telegraph and eventually to the development of radio, television, and cell phones. A whole new world of communication evolved that has profoundly changed the world we live in. The use of electromagnetic radiation, or waves, for therapeutic purposes began in the early 20th century when physicians began using high-frequency currents to heat muscles and joints.1 The penetration of electromagnetic waves through body tissues enabled deeper heating than superficial heating devices (such as hot packs applied to the skin). Eventually, the development of devices that produce electromagnetic waves popularized what became known as diathermy. Originally diathermy included "ultrasonic" therapy (ultrasound);2 however, the therapeutic effect of ultrasound is produced by mechanical vibrations, not electromagnetic waves (see Chapter 4). Today diathermy includes only therapeutic devices that produce electromagnetic waves from the microwave and radio frequency sections of the electromagnetic spectrum.