Relative Acoustic Transmission of Topical Preparations Used With Therapeutic Ultrasound

Difference in Tissue Temperature After Therapeutic Ultrasound Using Biofreeze Mixture and Ultrasound Gel as Coupling Media

“…Unfortunately, many of the topical analgesic gels or creams do not have similar transmission rates of ultrasound energy to ultrasound gel or water. 2,7 For example, another commonly used topical analgesic, Flexall (Ari-Med Pharmaceuticals, Tempe, Arizona), was compared with ultrasound gel at a 1:1 ratio of Flexall and ultrasound gel. 6 The Flexall mixture did not allow for the same level of intramuscular tissue temperature rise as the 100% ultrasound gel.…”

“…4,5 Although topical analgesics are used as coupling media, they are not always successful at allowing the transmission of ultrasound energy from the device into the tissues. Many topical analgesics have been shown to have poor transmission of ultrasound energy, 6,7 but some have qualities that may aid in the better transmission of ultrasound energy. First, aqueous gel-based analgesics have been shown to allow the transmission of ultrasound energy better than cream-based agents.…”

“…First, aqueous gel-based analgesics have been shown to allow the transmission of ultrasound energy better than cream-based agents. 7 Second, using a mixture of topical analgesic and ultra-sound gel has allowed for adequate transmission of ultrasound energy. 8,9 Biofreeze (Hygenic Corp, Akron, Ohio) is a menthol (4%)-based topical analgesic gel often used as a coupling medium during ultrasound treatments to create an additive effect for pain relief.…”

“…3 When Biofreeze has been used as a ultrasound coupling medium by itself, it has been shown to have poor transmission of ultrasound energy. 7 Although, by itself, Biofreeze has shown to be a poor transmitter of ultrasound energy, it may work well if mixed with ultrasound gel. The purpose of this study is to determine whether there is a difference in 1-part Biofreeze and 3-parts ultrasound gel compared with regular ultrasound gel in conduction ultrasound energy measured by intramuscular tissue temperature and whether there is a different perception of heat by the study participants when the Biofreeze mixture is used compared with ultrasound gel.…”

“…During our study, we used a frequency of 3 MHz, but previous studies using 1-MHz frequency have shown poor results when topical analgesics are used as a coupling medium. 6,8 When comparing Biofreeze's relative transmission of ultrasound energy to 100% ultrasound gel measured by a power meter, Cage et al 7 found that 3 MHz allowed for a greater transmission of ultrasound energy than 1 MHz. With Biofreeze, 3 MHz allowed for 79% of energy to be transmitted, whereas 1 MHz allowed for 60% of the energy to be transmitted.…”