2. Interaction of ultrasound

Ultrasonic waves are mechanical waves, which propagate in a medium (such as liquid, gas, solid and biological tissue). The propagation of ultrasonic waves is related to the transport of energy.

2.1. Phenomena accompanying the ultrasound wave

The intensity of the ultrasound wave (the maximum pressure value) generated by the us4R™ should not constitute a hazard for test subjects. Nevertheless, it is important to understand how ultrasound interacts with tissues and realize the possible bioeffects caused by mechanical waves.

These bio-effects fall within two categories: mechanical – related to the possibility of cavitation, and thermal – related to the absorption of wave energy by the tissue, which is converted into heat. The amplitude of an ultrasound wave propagating in any absorbing medium, such as a soft tissue, decreases with distance. Damping caused by the absorption and dissipation of the wave leads to energy loss. In the absorption process, part of the energy is converted into heat.

For a detailed examination of ultrasound safety, please consult The Safe Use of Ultrasound in Medical Diagnosis, 3rd ed., edited by Gail ter Haar.

Attention

The user creating a new transmit schema for the us4R™ should always consider the mentioned effects of the ultrasonic wave in a given medium/propagation environment.