69. ULTRASOUNDS: PULSED WAVES Flashcards
1
Q
- What is the speed of sound in Soft Tissue?
A
- 1540 m / s
2
Q
- What characteristics determine the Speed of Sound of the medium?
A
- the density of the medium
- the stiffness of the medium
3
Q
- What is Stiffness?
A
- this is the ability of an object to resist compression
4
Q
- What is Density?
A
- this is the relative weight of the material
5
Q
- What does an increase in Stiffness result in?
A
- it increases the speed of sound of the medium
6
Q
- What does an increase in Density result in?
A
- it decreases the speed
7
Q
- What do Continuous Wave sounds fail to do in Diagnostic Ultrasounds?
A
- they fail to create Anatomic Images
8
Q
- What do Imaging systems produce?
A
- they produce short bursts (pulses) of acoustic energy
- these create a picture of anatomy
9
Q
- Define the Pulse of an Ultrasound?
A
- it is the collection of cycles that travel together
10
Q
- What two components do Pulsed Ultrasounds have?
A
- Transmitting
- this is considered on time
- Receiving
- this is considered off time
11
Q
- What are the 5 parameters that describe Pulsed Sounds completely?
A
- Pulse Duration
- Spatial Pulse Length
- Pulse Repetition Period
- Pulse Repetition Frequency
- Duty Factor
12
Q
- How do we calculate the Duty Factor?
A
13
Q
- Label this image.
A
- Pulse Duration (µs)
- this could also be the Spatial Pulse Length (mm)
- Pulse Repetition Period (µs)
- Transmit time of the sound waves
- Receive time of the echoes
14
Q
- What is the depth of view?
A
- this describes the maximum distance into the body
- that an ultrasound system is imaging
15
Q
- What indicated depth in an Ultrasound?
A
- the markers along the edge of the image
17
Q
- What does this image show?
A
- this shows Deep Imaging
- the structure that is being images is far inside the body
18
Q
- What does this image show?
A
- this shows Shallow Imaging
- there is a shorter Pulse Repetition period
- the structure being images is closer to the surface
