Physics 2 Test chapters 14 &15 Flashcards
Which component of an Ultrasound system is responsible for organization and time?
Master synchronizer
Pg 216
Which component of an Ultrasound system creates an electrical signal that excites the PZT?
Pulser
Pg 217
Know the anatomy of a TGC curve
Near gain Delay Slope Knee Far gain Pg 228
What part creates the firing pattern for a phased array system?
Beam Former
Pg 221
What are all of the receiver functions?
Amplification Compensation Compression Demodulation Reject Pg 223
Acoustic power of a sound beam is determined by what part of a pulser?
Voltage
Pg 237
What type of pulser generates constant electrical signal?
Continuous wave
Pg 236
What is the receiver function that will improve signal to noise?
increasing output power is the most common way to improve signal to noise. ???
pg 219
What is the receiver function that has t do with demodulization?
Rectification
Or
Smoothing
Pg 232
What is the receiver function that keeps ______ within range of the human eye?
Compression
Gray scale
Pg 230
What is the receiver function that is not adjustable by the sonographer?
Demodulation
Pg 232
When an image is too dark or too bright, what are your two options to adjust the image?
output power (if image is too bright) and receiver gain (if image is too dark)
Which receiver function treats signals differently depending on depth?
Compensation
Pg 226
What is the receiver function that affects the weak signals, leaving the strong signals unchanged?
Reject
Pg 233
When PRP is long, PRF will be?
Lower
Pg 220
Know all six components of an ultrasound system
Transducer Pulser and beam former Receiver Display Storage Master synchronizer Pg 216
What should you do if an ultrasound system displays reflectors only in the far region?
Adjust the systems compensation
pg 238
What is the best choice if the entire image is too bright?
Decrease the output power
pg 238
Which component will affect strength of every pulse transmitted into the body?
Amplification
Pg 224
What are some disadvantages of analog scan converters?
image fade image flicker instability deterioration pg 243
Which electronic component is required for gray scale imaging?
scan converter??
pg. 241
Analog Scan Converter? (Pg. 243
Read magnification
A part of a frozen image is zoomed up on and it makes the image distorted. Number of pixels stay the same they are just larger.
pg 250
Temporal resolution may be improved if the region of interest is _____ in comparison to the original?
if the bottom of the region of interest is shallower that the original image’s depth of view
pg. 252
Advantages of an analog scan converter
The spatial resolution (image detail) is excellent because of the large number of storage elements.
These numbers can be unlimited and continuous range of values.
pg 242 maybe more???
Real World Numbers
How to calculate how many shades of gray there are (pg. 246)
for example: how many possible shades of grey if you have 3 bits. (2x2x2=8)
pg 246
How many bits are needed to store certain amount of shades of gray (how to calculate this)
I bet the question is going to be like #9 on the Q&A
pg 262
What are the preprocessing functions?
All the changes made to an image before storage. * time gain compensation * log compression * write magnification * persistence * spatial compounding * edge enhancement * fill in interpolation pg 249
Know about pixels
Smallest building block of a digital picture; number of picture elements per inch
Low pixel density: few pixels/inch, larger pixels, less detailed image, lower spatial resolution
High pixel density: many pixels/inch, smaller pixels, more detailed image, higher spatial resolution
pg. 244
Know the diagram on pg. 247 about digital and analog
analog——->analog-to-digital converter ——-> digital memory (zeros and ones) ——-> digital-to-analog converter ——–> analog
pg. 247
Bistable imaging
Images are composed of black and white shades only.
pg 239
Spatial resolution of the CRT is determined by what? (Beth said “CRT” means “screen/monitor”)
Pixel density
Pg. 377
What function is related to the ability for us to see shades of gray?
Compression
pg 230
Real world vs. computer world
real world is analog and computer world is digital
242
While scanning, you increase your overall gain. Is this preprocessing or postprocessing?
Preprocessing
pg. 249
Preprocessing
The manipulation of image data before storage in the scan converter; sonographer controls this; alters image data forever and cannot be reversed/undone
pg. 249
Postprocessing
The manipulation of image data after storage in the scan converter; sonographer controls this; since this occurs after A-to-D conversion and storage, all changes can be reversed; any alterations to a frozen image must be postprocessing
Any change after freeze frame Black/white inversion Read magnification Contrast variation 3-D rendering pg. 249
What portion converts data into numbers?
Digital scan converter
Pg. 243
What are the advantages of coded excitation?
Higher signal-to-noise ratio Improved axial resolution Improved spatial resolution Improved contrast resolution Deeper penetration pg. 253
What is fill-in interpolation?
Fill in the gaps of missing data in a way that cannot be detected by the observer; form of preprocessing
pg. 257
What is coded excitation? (where does it occur)
Creates very long sound pulses containing a wide range of frquencies. Occurs in the pulser.
pg. 253
What is spatial compounding?
Using sonographic information from several different imaging angles to produce a single image
pg. 254
What is elastography?
Produces images from sound reflection. Theory of elastography is that tissue will deform differently following the application of a force. Estimates tissue stiffness.
pg 258
Which technology reduces speckle and improves spatial resolution?
Spatial compounding
pg. 254
What is speckle?
is noise resulting from constructive and destructive interference of small sound wavelets.
pg 374
Which technology provides a history of past frames that overlay on the present frames?
temporal compounding, persistence, or temporal averaging
pg 256
