Uses of Ultrasound
Echo Sounding
This technique is used to detect defects or flaws inside pieces of metal. It works on the principle of a pulse of ultrasound being transmitted into a metal component to be assessed. A receiver then picks up the echoes of the ultrasonic waves from different parts of the metal and shows the results on a cathode ray oscilloscope. The animation below shows how ultrasonic echo sounding works.
Pre Natal Scanning
Ultrasound waves are partially reflected at the boundaries between two different materials. Ultrasound reflects well at the boundaries between soft tissue and air or bone and air. The speed of ultrasound depends on the material in which it is travelling. Ultrasound waves travel faster in dense materials as the molecules a packed tightly together and slower in less dense materials. Thus in body tissue which is less dense ultrasound travels slowly with a corresponding decrease in wavelength and in dense material like bones it travels faster with a corresponding increase in wavelength. These properties of ultrasound are applied in pre natal scanners. The animation below explains how a pre natal scanner works.
Pre Natal Scanning |
---|
Ultrasound is used for pre-natal scanning to monitors the baby’s development in the uterus. Ultrasound is emitted from a transducer which also detects the echoes which are analysed by a computer to give a moving picture of the baby on a screen. Ultrasound is reflected at the boundaries between solid structures such as bones and muscles or tissues and body fluid present in the womb and displayed on the screen as grey and white areas. Hollow area like the eye sockets or heart chambers do not reflect the ultrasound as these appear as dark or black areas. This technique can also be used to analyse soft organs like the liver or gall bladder. |
Advantages and Disadvanges of Ultrasound Scanning
Advantages of Ultrasound Scanning |
|
Disadvantage of Ultrasound Scanning |
|