How Does an Ultrasound Machine Detect Reflected Waves?

In summary, an ultrasound machine detects reflected waves by using a piezoelectric crystal that converts electrical energy into sound waves and vice versa. This crystal acts as both a speaker and a microphone, producing sound waves when a voltage is applied to it and generating an electrical current when sound waves hit it. The crystal also plays a role in producing images by interpreting the vibrations and transmitting them through the machine's circuitry. The frequency of the wave can affect its absorption, with higher frequencies being more easily absorbed due to their shorter wavelengths.
  • #1
Mathysics
37
0
how does ultrasound machine detects the reflected wave?

i have read a bit of information and unfortunately I am still unsure how they detect the wave.

"The rapid shape changes, or vibrations, of the crystals produce sound waves that travel outward. Conversely, when sound or pressure waves hit the crystals, they emit electrical currents. Therefore, the same crystals can be used to send and receive sound waves."

I don't understand how the change in electric field can be related to the detection of the wave. please help
 
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  • #2
The speaker and microphone are the same thing.
If you put a voltage across the piezo crystal it changes shape and emits a sound, if you change it's shape, by a sound hitting it, it generates a voltage.

This is true of most microphones/speakers
 
  • #3
mgb_phys said:
The speaker and microphone are the same thing.
If you put a voltage across the piezo crystal it changes shape and emits a sound, if you change it's shape, by a sound hitting it, it generates a voltage.

This is true of most microphones/speakers
So when this happens this is the reverse of the piezoelectric effect? (from mechanical energy to electrical energy.)

And the transducer receives sound wave because of this reverse piezoelectric effect?

also there is the other bit that i don't understand

"the crystal will be changed in the same way as when crystal the crystal was generating ultrasound. In this case the changing crystal will cause a changing electric field to be produced across the crystal"

to be honest, I have no idea what they talk about at all. :(
 
Last edited:
  • #4
Oscillation of sound to produce an image. Instead of using gamma rays to produce material densities, you use sound to reflect surfaces. When sound is produced by a device and interpreted in a certain way, it can produce images.
 
  • #5
threadmark said:
Oscillation of sound to produce an image. Instead of using gamma rays to produce material densities, you use sound to reflect surfaces. When sound is produced by a device and interpreted in a certain way, it can produce images.
yes it calculates the time that takes to travel back to the transducer to produce an image.

but i don't really get this staement below "the crystal will be changed in the same way as when crystal the crystal was generating ultrasound. In this case the changing crystal will cause a changing electric field to be produced across the crystal"
 
  • #6
The crystal is a sensor, it creates vibrations and interprets vibrations. the change from sound to an electric signal is in the circuitry of the machine. The crystal interprets sound to be transmitted over the circuit.
 
  • #7
threadmark said:
The crystal is a sensor, it creates vibrations and interprets vibrations. the change from sound to an electric signal is in the circuitry of the machine. The crystal interprets sound to be transmitted over the circuit.

oops sorry i understand now thx!
 
  • #8
just wondering, would the change in amplitude (voltage) has any effect on this?
 
  • #9
yes?
 
  • #10
hey here is another question :S

When the frequency of the wave is too high it will be absorbed easily? I don't understand why. Is it because of the increase in wavelength?
 

FAQ: How Does an Ultrasound Machine Detect Reflected Waves?

What is an ultrasound machine?

An ultrasound machine is a medical device that uses high-frequency sound waves to produce images of structures inside the body.

How does an ultrasound machine work?

An ultrasound machine works by emitting high-frequency sound waves into the body and then detecting the echoes that bounce back from the internal structures. These echoes are then processed and translated into images by the machine.

What are the components of an ultrasound machine?

An ultrasound machine typically consists of a transducer, which emits and receives the sound waves, a computer, which processes the signals, and a monitor, which displays the images.

How does an ultrasound machine detect reflected waves?

An ultrasound machine uses a technique called pulse-echo imaging to detect reflected waves. The transducer emits a short burst of sound waves, which then bounce off internal structures and return to the transducer. The machine measures the time it takes for the waves to return and uses this information to create an image.

What are the uses of ultrasound imaging?

Ultrasound imaging is commonly used in medical settings to visualize internal structures such as organs, blood vessels, and fetuses. It can also be used for therapeutic purposes, such as breaking up kidney stones or helping guide medical procedures.

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