"Due to the law of the conservation of energy, all of the sound energy attenuated by tissues must be converted to other forms of energy. The majority of this is turned into heat. As such, it is possible for ultrasound to raise tissue temperature by up to 1.5°C. For sensitive tissues (eg. fetal) this rise in temperature may have deleterious effects if present for an extended period of time."
"The thermal index (TI), is the ratio of the power produced by the transducer to the power required to raise a tissue in the beam by 1°C."
"The mechanical bioeffect of ultrasound refers to damage caused by the actual oscillation of the sound wave on tissue. The most common is referred to as cavitation and is caused by the oscillation of small gas bubbles within the ultrasound field. In certain circumstances, these bubbles may grow in size or collapse generating very high energies to adjacent tissue. This can increase tissue temperature by more than 1000°C."
"Due to the law of the conservation of energy, all of the sound energy attenuated by tissues must be converted to other forms of energy. The majority of this is turned into heat. As such, it is possible for ultrasound to raise tissue temperature by up to 1.5°C. For sensitive tissues (eg. fetal) this rise in temperature may have deleterious effects if present for an extended period of time."
Expected headings
"Thermal effects"
"Mechanical effects"