Physics 12-14 Final Flashcards
Lateral resolution does not improve with multi-focusing. Tor F
False
Imaging depth and frame rate are directly related. Tor F
True
On the annular phased array tranducer, which part of the beam is used for the information? A. all of it B. near zone C. far zone D. focal zone
D. focal zone
100 x 1/1000 second = 1/10 sec What is the frame rate? A. 1Hz B. .1Hz C. 10 Hz D. 100 Hz
C. 10 Hz
Temporal resolution pertains to
A. accuracy in time
B. the abilityto distinctly identify 2 structures that are very close together when they are sided by side
C. the ability to distinctly identify 2 structures when they are in front of each other
A. accuracy in time
Frame rate is determined by what 2 things?
A. depth of imaging and lateral resolution
B. sounds speed in the medium and the depth of imaging
C. sounds speed in the medium and sector size
B. sounds speed in the medium and the depth of imaging
Rendering creates an image from __________ data acquired during the US exam.
A. 3-D
B. 2-D
C. 4-D
A. 3-D
When you excite the innstals and progressively excite the outer crystals to diminish lobe artifact, this is called
A. side lobe artifact
B. apodization
C. subdicing
B. apodization
The sonographer can control the number of pulses in each picture. Tor F
True
Sector size is also called
A. multi-focusing
B. Field of view
C. line density
B. field of view
A sonographer increases the line density from line per degree of sector to 5 lines per degree of sector. What is the most likely consequence of the action? A. temporal resolution decreases B. imaging quality decreases C. frame rate increases D. temporal resolution increases
A. Temporal resolution decreases
The linear sequential array trnsducers have crystals that are \_\_\_\_\_\_ wavelength in width. A. 1 B. 1.5 C. 2 D. .5
A. 1
All the following decrease temporal resolution except: A. deeper imaging B. multi focus C. lower frame rate D. narrower sector
D. narrower sector
All the following will cause low line density except: A. fewer pulses per frame B. tightly packed lines C. higher frame rate D. shorter T frame
B. tightly packed lines
What is the unit for frame rate?
A. dB
B. cm
C. Hz
C. hz
Which of the following is best described as mechanically steered and multi-focus A. linear phased trans. B. mechanical trans. C. annular sequential array trans. D. annular phased array trans.
D. annular phased array trans.
The image shape for convex image will be rectangle. Tor F
False
Temporal resolution is reduced when few images are displayed per second. TorF
True
Is the sonographer able to change the spacing between sound beams. Tor F
True
With high line density, each image contains more detail, this known as A. improved temporal resolution B. improved line density C. improved spatial resolution D. improved sector size
C. improved spatial resolution
A linear phased array transducer has 128 crystals. How many of these crystals are fired to create a single sound beam?
A. 128
B. 1
C. a small group
A. 128
With vector array images, the top of the image is
A. flat
B. convex
A. flat
When one ring of the annular array transducer malfunctions, the entire image is lost. Tor F
False
Mechanical transducers have only one active element. The shape of the element resembles a
A. coin
B. bull’s eye
C. rectangle
A.coin
When one element in a linear sequential array is damaged, only the portion of the image extending directly below the damaged element is affected. Tor F
True
The image created by a linear phased array is a
A. fan shaped
B. rectangular shaped
C blunted sector shaped
A. fan shaped
Trendy way of describing real time 3-D imaging
A. 4-D
B. 2-D
C. 2-D array
A. 4-D
With annular phased array transducers, electronic steering creates the 2-D image. Tor F
False
If a spike pattern has a straight line on a linear phased array, is the beam Focused or Unfocused
Unfocused
Can linear sequential array sound beams be steered electronically?
Yes
In convex sequential arrays, all the crystals are fired simultaneously to create each sound beam. Tor F
False
Slice thickness is also called elevational resolution. Tor F
True
Side lobe artifact will
A. degrade lateral resolution
B. improve lateral resolution
A. degrade lateral resolution
When crystals are divided into a group of smaller crystals called sub-elements and are electrically joined and act as a single crystal to reduce grating lobes, this is called
A. subdicing
B. apodization
C. resolution
A. subdicing
Is patient exposure levels to ultrasound energy altered when the sonographer changes amplification?
No
Smoothing converts all negative voltages into positive voltages. Tor F
False
Which does not belong as a major component in the ultrasound system A. master synchronizer B. transducer C. switch D. pulser and beam former
Switch
When signal-to-noise ratio is high, the signal is much stronger than the noise and the image is of high quality. Tor F
True
In the amplification process, the typical values are measured in dB. The range is A. 50-80dB B. 60-100dB C.60-90dB D. 50-100dB
B 60-100dB
Compensation is performed twice. Tor F
False
This allows the sonographerto control whether the low-level gray scale information within the data will appear on the displayed imag. A. demodulation B. reject C. compression D. compensation
B. reject
What does ALARA mean
As low as reasonably achievable
Place these functions in the order in which the ultrasound system performs them A. Reject B. amplification C. demodulation D. compensation E. compression
B. amplification D. compensation E. compression C. demodulation A. reject
Receiver gain is called A. demodulation B. reject C. amplification D. spatial resolution
C. amplification
Can the sonographer change demodulation?
No
All electrical signals in the receiver are affected ______ by amplification
A. partially
B. identically
B. identically
Preamplification occurs as close to the active element as is practical, often
A. in the display
B. in the master synchronizer
C. in the transducer
C. in transducer
The pulser creates electrical signals that excite the PZT crystals and create sound beams. When pulser voltage is high, the transducer’ active element vibrates more forcefully and transmits stronger sound beams into the body. Tor F
True
Another name for pulser voltage is A. log compression B. threshold C. receiver gain D. transmitter output
D. transmitter output
Can output power alone make an image of uniform brightness from top to bottom. Tor F
No
Which of the following choices is best when the image on your ultrasound system is too bright everywhere? A. decrease the amplification or gain B. use a higher freq. transducer C. decrease the output power D. adjust the reject level
C. decrease the output power
Which of the following choices is best when the image on your ultrasound system displays reflectors only in a region far from the transducer but no reflectors in a region close to the transducer? a. adjust the systems compensation B. use a higher freq. transducer C. decrease the output power D. adjust the reject level
A. adjust the systems compensation
Both levels of reject can be adjusted by the sonographer. TorF
False
