Ultrasound

Ultrasound

1. Risks

   • Non-ionising
   • Safer than X-rays

2. Formula

   • S=V*T
     • T is the time taken in seconds
     • S is the distance travelled in metres
     • V is the speed of the ultrasound wave in metres per second

3. Uses

   • Soft tissue
     • Eye
   • Therapy
     • Shatter kidney stones into smaller pieces
   • Scan unborn babies

4. Human ear

   • Detects frequencies between 2Hz and 20,000Hz
     • Higher frequencies than this are called ultrasound waves

5. Electronic systems

   • Can produce ultrasound waves
   • When a wave meets a boundary between two materials part of the wave reflects
     • In the time between a transmitter to a boundary and back
       • Twice the distance to a boundary
     • The wave travels back to though the material to a detector
       • The time it takes to reach the detector can be used to calculate how far away the boundary is
         • The results may be processed by a computer to give an image

6. Ultrasound waves

   • Above 20,000 Hz
   • Ultrasounds are sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is no different from 'normal' (audible) sound in its physical properties, except in that humans cannot hear it.

7. Ultrasound waves in medicine

   • Destruction of kidney stones
   • Ultrasound scanning

8. How ultrasound scans work A small device called an ultrasound probe is used, which gives off high-frequency sound waves. You can't hear these sound waves, but when they bounce off different parts of the body, they create "echoes" that are picked up by the probe and turned into a moving image. This image is displayed on a monitor while the scan is carried out.

   • external ultrasound scan – the probe is moved over the skin internal ultrasound scan – the probe is inserted into the body endoscopic ultrasound scan – the probe is attached to a long, thin, flexible tube (an endoscope) and passed further into the body
     • Measuring the speed of blood flow in the body

Images and files in the map