biophysics Sgl quiz

What is the definition of ultrasound waves?

They are sound waves of frequencies above the audible sound that can penetrate deeply in the body.

What does SONAR stand for?

Sound Navigation and Ranging.

Who was the first important successful application of sonar in medical diagnosis?

Karl Theodore Dussik.

How does the velocity of ultrasound transmission depend on tissue?

It depends primarily on the physical makeup of the tissue.

What is a sonogram?

A computer picture of the intended object inside the body created by high energy ultrasound waves.

What are the main components involved in performing a sonogram?

Generation, transmission, reflection, reception, processing.

What two tissue characteristics significantly affect ultrasound velocity?

Compressibility and density of the tissue material.

What is the ultrasound velocity in bones?

4080 m/s.

How is ultrasound beam intensity defined?

The sound power per unit area normal to the direction of propagation.

What is defined as beam attenuation?

The reduction in the beam intensity by reflection, refraction, and absorption.

What are some applications of medical sonography?

Creating images, diagnosing diseases, examining internal organs.

What is the advantage of using sonography over other imaging techniques?

It does not use harmful ionizing radiation.

What factor greatly affects the amount of reflected ultrasound beam from the skin?

Acoustic impedance.

What is the role of lubricating gel in ultrasound procedures?

It minimizes reflection by having similar acoustic impedance to that of the skin.

How does the angle of incidence affect ultrasound transmission?

A larger angle of incidence results in less transmitted beam and more reflected beam.

How is echo in ultrasound defined?

Reflected ultrasound waves from the intended object back to the transducer.

What is Doppler sonography primarily used for?

To monitor the movement of blood, fluids, and tissues and their relative velocities.

What is the difference between Continuous Wave Doppler and Pulsed Wave Doppler?

CW Doppler uses two sets of crystals for continuous signals, while PW Doppler uses one set that emits short pulses.

What frequency range is typically used in sonographic instruments?

1 - 20 MHz.

What are piezoelectric and ferroelectric crystals?

Materials used in ultrasound transducers to convert electrical energy into ultrasonic waves.

What is the fundamental resonance frequency of a crystal?

The frequency at which the crystal oscillates based on its thickness and speed of sound in the material.

How does viscosity affect ultrasound absorption?

Higher viscosity increases energy absorption and reduces ultrasound intensity.

What is the impact of frequency on ultrasound absorption in soft tissues?

Absorption is nearly doubled when the frequency is doubled.