Ultrasound in medicine and industry

Ultrasound lets doctors see inside the body without cutting it — and even break up stones inside it.

Ultrasound scanning

Ultrasound sent from a transmitter on a patient's chest reflects from the walls inside the heart. The reflected waves give information on how much blood the heart pumps in one beat, the size of the heart and the heart rate.

Checking a baby

Ultrasound shows the condition of a pregnant mother's womb and of the baby inside it.

Breaking kidney stones

Ultrasound aimed at kidney stones — crystals of calcium oxalate — makes them vibrate until they break apart. The method is called lithotripsy.

Finding hidden flaws

High-frequency ultrasound in a solid does not pass into air, so an air gap reflects it. This finds dangerous cavities and cracks inside solid parts such as aircraft parts.

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Figures 4.37 and 4.38 — a pregnant mother having an ultrasound scan, and the ultrasound image of the baby in the womb.

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Figure 4.39 — a lithotripsy machine used to break up kidney stones with ultrasound.

Ultrasound is also used in aids that help blind people find their way.

Welding with ultrasound

Ultrasound is used to weld metal parts. The metals are held firmly in contact and ultrasound is made to strike them. The vibration rubs the two metal sheets together, producing a great deal of heat, and at the points of contact they melt and fuse together.