Relative Acoustic Transmission of Topical Preparations Used With Therapeutic Ultrasound

Topical agents suspended in aqueous gels are generally more effective in transmitting US energy, while many cream-based agents are less effective, particularly at 1MHz frequency. Many agents that are commonly used to provide a sensory effect, such as topical analgesic creams, may block US transmission. Agents that reduce US transmission may lead to poor phonophoresis results and are likely to minimize the therapeutic effects of US.