The applications of ultrasonics in the medical field have involved analysis and treatment. The developments in the medical field appear to be very promising. The effect of ultrasonics on tissues has been investigated. The heating and mechanical effects have been isolated. The conclusion is that there is an effect outside of the heating effect.
The effects of the changes produced by high intensity sound upon the central nervous system has been investigated. The results show that nerve cells are particularly sensitive to ultrasonics, while blood vessels and nerve fibers are much more resistant. A study of the therapeutic effect of ultrasonics shows that the heat which is produced plays the major role. However, ultrasonics also produces a mechanical effect. Ultrasonics has been used to produce deep-seated heating in the treatment of arthritis. The cerebral ventricular geometry has been portrayed by means of ultrasonic techniques. The head is immersed in water. An underwater projector sends an ultrasonic wave through the head. A hydrophone picks up the transmitted sound. A frequency of 2.5 megacycles was used. A scanning system together with a facsimile-type recorder presents the ultrasonogram in the form of a picture showing the cerebral ventricular geometry. This method provides a means for the detection of brain tumors similar to that of the X-ray.
Recent work on tumor detection employs ultrasonic waves and echo-ranging techniques with cathode-ray presentation. the pulses are sent into the body and the echos return in different intensities depending upon the difference in acoustical impedance of the malignant and nonmalignant tissues and in different times depending upon the depths of the reflecting boundaries.
A small version of the ultrasonic drill has been developed for use by dentists in drilling teeth. the advantages of the ultrasonic drill is reduction in pain and improved definition of the drilled area.