Lecture 4 Flashcards
Different transducers/probes have different _________
Frequencies
Type of frequency set out from the probe is called
Fundamental frequency
Aka operational frequency
Aka transmit frequency
Fo
2 features of higher frequency
Better quality image
Less penetration/doesn’t go deep into body
2 qualities of low frequency
Worse quality image
Better penetration (think of how bass sounds go through walls)
One way to achieve higher frequency waves is the use of ____
Harmonics
As sound travels through tissue it changes ________
Shape
The change of sinusoidal waves to non sinusodial waveforms is called
Non-linear propagation
Sound moves ______ in more dense areas
Faster
Nonsinusidal waves contain additional _____
Frequencies
When the fundamental frequency is sent out, multiple _______ _______ are produced within the tissue
Harmonic frequencies
Less sinusoidal shape = ______ harmonics
Stronger
Harmonics send out one frequency and get back
Several higher frequencies
In a continuous wave, cycles repeat _______
Indefinitely
In ultrasound we use ________ ______ which are ______ _______
Pulsed ultrasound which are pulsed waves
What is a pulse
A few cycles of ultrasound then separated by gaps of no ultrasound
