Ultrasound Physics and Instrumentation

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Questions and Answers

What event spurred the advancement of SONAR technology?

The discovery of X-rays

The development of MRI

World War I's naval warfare (correct)

World War II

Who identified the piezoelectric effect?

Spallanzani

The Dussik brothers

The Curie brothers (correct)

Langevin

What was the focus of Dussik's pioneering study?

The brain (correct)

The liver

The heart

The kidneys

In what year did Spallanzani explore the discovery of sound beyond the audible spectrum?

1794 Signup and view all the answers

What was the development of in the 1940s?

Ultrasound technology Signup and view all the answers

Who created an early ultrasound device using piezoelectric principles?

Langevin Signup and view all the answers

What was developed in the 1930s?

Diagnostic uses for ultrasound Signup and view all the answers

What was the outcome of institutions worldwide developing pulsed ultrasound technology?

'B' Mode imaging Signup and view all the answers

What expansion occurred in ultrasound technology?

From 3D to 4D Signup and view all the answers

What type of energy do sound waves carry?

Mechanical energy Signup and view all the answers

What is the standard unit of power?

Watt Signup and view all the answers

How many milliwatts are in a single Watt?

1,000 Signup and view all the answers

What is intensity in the context of sound waves?

The rate at which energy passes through a unit area Signup and view all the answers

What is the unit of beam area in ultrasound?

Centimeters squared Signup and view all the answers

What happens to intensity when the area increases?

It decreases Signup and view all the answers

What is the effect of focusing on intensity?

It increases intensity Signup and view all the answers

What happens to an ultrasound pulse as it travels through a medium?

It becomes weaker Signup and view all the answers

What is the term for the weakening of an ultrasound pulse as it travels through a medium?

Attenuation Signup and view all the answers

What does the sonographer adjust to achieve optimal imaging depth?

PRF Signup and view all the answers

What is the relationship between PRP and PRF?

PRP is the reciprocal of PRF Signup and view all the answers

What happens to PRP when PRF increases?

PRP decreases Signup and view all the answers

What is the typical range of PRP values in clinical imaging?

100 microseconds to 1 millisecond Signup and view all the answers

What influences the determination of PRP?

The sound source Signup and view all the answers

What is pulse-repetition period (PRP)?

The time between two consecutive pulses Signup and view all the answers

What is the effect of increasing PRF on the time between pulses?

The time between pulses decreases Signup and view all the answers

What can the operator adjust to change the PRP?

The PRF Signup and view all the answers

What is the unit of PRP?

Milliseconds or any unit of time Signup and view all the answers

What is the formula for SPL?

SPL(mm) = n × wavelength(mm) Signup and view all the answers

What is the relationship between frequency and SPL?

SPL decreases with increasing frequency Signup and view all the answers

What is the axial resolution dependent on?

SPL Signup and view all the answers

What is the length of space over which a pulse occurs?

SPL Signup and view all the answers

What is the effect of increasing path length on attenuation?

Attenuation increases Signup and view all the answers

What is the effect of higher frequencies on attenuation?

Attenuation increases Signup and view all the answers

How does the attenuation coefficient change with frequency?

It increases by 0.5 dB/cm per MHz Signup and view all the answers

What is the average loss of attenuation per MHz frequency?

0.5 dB/cm per MHz Signup and view all the answers

What is the unit of measurement for acoustic impedance?

kg/(m²·s) Signup and view all the answers

What is the formula for calculating acoustic impedance?

Z = ρ x C Signup and view all the answers

What happens when there is a substantial difference in acoustic impedance between two tissues?

There is increased reflection of ultrasound Signup and view all the answers

What happens when the acoustic impedance of two tissues is similar?

There is greater transmission of ultrasound Signup and view all the answers

What is the density of air in kg/m³?

1.3 Signup and view all the answers

What is the speed of ultrasound in air in m/s?

330 Signup and view all the answers

What is the density of water in kg/m³?

1000 Signup and view all the answers

What is the speed of ultrasound in water in m/s?

1500 Signup and view all the answers

What is the density of blood in kg/m³?

1060 Signup and view all the answers

Study Notes

Evolution of Ultrasound Technology

Ultrasound technology evolved from SONAR technology, which was developed during World War I for naval warfare.
In 1880, Spallanzani discovered sound beyond the audible spectrum, leading to the development of ultrasound technology.
The Curie brothers, Pierre and Jacques, identified the piezoelectric effect in 1794, which is fundamental to later ultrasound technology.
In the 1930s, diagnostic uses for ultrasound started to emerge, marking a new era in medical imaging.
The real-time B-scan ultrasound was developed in the 1960s, and three-dimensional (3D) and four-dimensional (4D) ultrasound technology expanded in the following years.

Sound Wave Parameters: Power

Power is the capacity of a wave to displace particles within a medium.
The standard unit of power is the Watt (W), and in diagnostic ultrasound, power is commonly expressed in milliwatts (mW).
One milliwatt equates to one-thousandth of a Watt.

Sound Wave Parameters: Intensity

Intensity is the rate at which energy passes through a unit area.
Intensity is equal to the power in a wave divided by the area over which the power is spread.
Intensity units include milliwatts per centimeter squared (mW/cm2) and watts per centimeter squared (W/cm2).
An increase in area decreases intensity, while a decrease in area (focusing) increases intensity.

Attenuation

Attenuation is the progressive reduction in amplitude or intensity of ultrasound waves as they travel through a medium.
Attenuation is caused by the absorption of sound energy, the reflection and scattering of sound waves.
Factors influencing attenuation include path length, frequency, and tissue type.
Attenuation is measured in decibels (dB).

Pulse Repetition Period (PRP)

Pulse-repetition period (PRP) is the time from the beginning of one pulse to the beginning of the next one.
PRP is the reciprocal of Pulse Repetition Frequency (PRF), expressed in milliseconds or any unit of time.
PRP decreases while PRF increases because, when more pulses occur in a second, the time between them decreases.
Typical values for PRP in clinical imaging range from 100 microseconds to 1 millisecond.

Spatial Pulse Length (SPL)

Spatial pulse length (SPL) is the length of space over which a pulse occurs.
SPL is equal to wavelength multiplied by the number of cycles in the pulse.
SPL determines axial resolution.

Ultrasound Interaction with Tissue

Attenuation coefficient is half the frequency (MHz), resulting in an average loss of 0.5 dB/cm per MHz frequency.
Acoustic impedance (Z) is influenced by tissue density and the speed of ultrasound, and is calculated using the formula Z = ρ x C.
The transmission and reflection of ultrasound at tissue interfaces are influenced by acoustic impedance disparities.

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Description

Learn about the evolution of ultrasound technology, its discovery, and its applications in the medical industry. This quiz covers the basics of ultrasound physics and instrumentation.