- Ultrasound waves are produced by an ultrasound probe:
- An electric current is passed through a piezoelectric crystal:
- Act as transducers converting electrical energy into mechanical vibrations at high frequencies
- Generates ultrasound waves at the frequency of the voltage applied
- Ultrasound waves travel through a given medium
- When a structure is encountered some waves are reflected back towards the probe
- The probe detects returning waves:
- The pressure effect distorts the piezoelectric crystals producing an output voltage
- Converts the mechanical energy into electrical energy
- Output signals from the probe are then converted into an image:
- The time between the waves being sent out and returning is calculated
- Depth of a structure is determined by the time taken for a wave to return
- Pixels are created at the appropriate depth for returning waves
- The brightness of the pixel correlates with the strength of returning wave
- Multiple crystals are located within a probe:
- Positioned adjacent to each other in an “array”
- Connected electrically to generate a 2D image
- As the ultrasound probe both emits and receives the signal they are known as ‘transceivers’.
