Physics and Instrumentation Flashcards
5 functions of a ultrasound receiver
- Amplification
- Compensation
- Compression
- Demodulation
- Rejection
In that order
Spatial Resolution: LARD stands for
longitudinal, axial, radial, range, and depth resolution
The length of a single pulse is called the _____ ______ _______
Spacial Pulse Length
Axial (or LARD) resolution is dependent on the 1/2 the _____ ______ _____
1/2 the spacial pulse length
Axial (or LARD) resolution occurs in which axis? (X / Y / Z)
Z-Axis
Spatial Resolution: LATA stands for
Lateral, Angular, Transverse and Azimuthal
Lateral (or LATA) resolution occurs in which axis? (X / Y / Z)
X- Axis
Elevation resolution occurs in which axis? (X / Y / Z)
Y-Axis
The time required to complete one cycle is the __________
Period
The length of a single cycle measured as a distance is called the __________
Wavelength
The amount of time it take to complete a single pulse is the ________ __________
Pulse duration
The Length of a single pulse is the _______ _________ _________
Spatial Pulse Length
The amount of TIME from the begining of one pulse to the begining of the next pulse is the ______ ______ ______
Pulse repetition period
How is pulse repetition period related to pulse repetition frequency?
The inverse:
PRF = 1 / PRP
How is the Nyquist limit related to the pulse repetition frequency
Nyquist limit is 1/2 the PRF
Pulse repetition frequency is important to what type of resolution?
Temporal resolution
How is axial resolution related to spatial pulse length?
Axial resolution is 1/2 SPL
The number of cycles per second is the __________
Frequency
The _______ layer reduces reflection at the tissue/transducer interface
matching layer
The maximum spatial peak temporal average intensity to avoid thermal injury for unfocused US beam is _______
1W/cm^2
The maximum spatial peak temporal average intensity to avoid thermal injury for a FOCUSED US beam is _______
100mW/cm^2
=0.1W/cm^2
Amplitude is plotted on the Y axis and depth on the X axis in (A/B/M/2-D)-Mode Ultrasound
A-Mode ultrasound
Returning echos are plotted according to depth and amplitude with stronger echos appearing brighter in (A/B/M/2-D)-Mode Ultrasound
B-Mode ultrasound
Amplitude of returning echos are plotted as brightness on the and graphed at their distance on the Y axis vs time on the X axis in (A/B/M/2-D)-Mode Ultrasound
M-Mode ultrasound
(Density) * (Velocity) = ______ _______
(Z) Acoustic Impedance
The backing material improves _______ _______ by decreasing spacial pulse length
Axial Resolution
V/2T =
Resonant Frequency
As bandwidth increases, quality factor (increases/decreases)
decreases
Resonant Frequency / Bandwidth =
Quality Factor
The fraction of time that the ultrasound crystal is producing a pulse is known as the ______ _______
Duty Factor
Pulse Duration / Pulse Repetition Period
Duty Factor
(Radius of the transducers face)^2 / Wavelength =
Focal length
Damping material decreases the _______ _______ ________
Spacial pulse length
What is the frequency of an ultrasound probe with a wavelength of 0.308mm?
5 MHz
Velocity = (Frequency) x (Wavelength)
The ideal matching layer has a thickness _______ that of the wavelength
1/4
The optimal thickness of the piezoelectric crystal is _______ that of the wavelength
1/2
