If the bubbles contract towards the point of collapsing, they can build up very high temperatures
and pressures for a few tens of nanoseconds. These high temperatures and high pressures can produce
highly reactive chemicals called free radicals, and other potentially toxic compounds which, although
considered unlikely, could theoretically cause genetic damage. The rapid contraction of bubbles in
cavitation can also cause microjets of liquid which can damage cells. When diagnostic ultrasound is
focused on the lung or intestine of laboratory animals, which contain gas bubbles, these cavitation effects
can cause ruptures in very small blood vessels.