Principles of Physics in Ultrasound

Principles of Physics in Ultrasound

Physics has become an important part of medicine allowing specialist

doctors and radiographers to rapidly access a patient’s condition and

to help in long-term diagnosis.

This enables doctor’s to treat patients before their condition

deteriorates.

This procedure would not be possible without the use of X-rays, CAT

scans, MRI scans, ultrasound and endoscopes, which allow doctors to

see inside the body with little or no surgery.

Without such equipment doctors would be forced to use invasive

techniques, which could cause patients more harm as it increases the

risk of infection.

A sound or ultrasound wave consists of a mechanical disturbance of a

medium (gas, liquid or solid) which passes through the medium at a

fixed speed.

Sound waves consist of a disturbance of air molecules, the vibrations

which pass from molecule to molecules from the speaker to the ear of

the listener.

The rate at which particles in the medium vibrate in the disturbance

is the frequency or pitch of the sound measured in hertz

(cycles/sound).

As the pitch increases there comes a frequency at about 20kHz when the

sound is no longer audible and above the frequency disturbance, this

is know as ultrasound.

The first major breakthrough in the evolution of high frequency

echo-sounding techniques came when the piezo-electric effect in

certain crystals was discovered by Pierre and Jacques Curie in Paris

in 1880.

The turn of the century saw the invention of the Diode (component that

restricts the direction of movement, allows an electric current to

flow in one direction) and the Triode (type of vacu...

... middle of paper ...

... abnormalities of blood vessels such as

aneurysms

It can help to look for blockages of blood flow in blood vessels, such

as a deep vein thrombosis, abnormalities of the heart valves or other

heart structures (this type of examination is called echocardiography)

Without the use of physics the medical equipment, such as X-rays,

ultrasounds and endoscopes, would not exist.

This would cause diagnosis of patients to be a long and complex

procedure.

This equipment has revolutionised medical practise and will continue

doing so for years to come.

References

http://www.nelh.nhs.uk/screening/fasp/history.htm.

Physics for medical imaging, RF Farr and PJ Allisy Roberts.

Basic physics for medical imaging, Edwin GA Aird.

Physics and Instrumentation of Diagnostic Medical Ultrasound, Peter

Fish.