Ultrasound is a therapeutic treatment using high-frequency sound waves in the region of soft tissue injuries. Sound vibrations penetrate deep into tissue, causing a heat response. These vibrations and heat break down and disperse calcium and other hard tissue accumulations. It uses gel to conduct the sound waves. This gel may momentarily feel cool, but otherwise, most patients feel nothing at the time of treatment. Relief comes a few minutes to hours later. The rise in temperature, increased blood flow, and relaxed muscle spasms speed the healing process.