You are using a 4 MHz transducer and have adjusted the time gain compensation (TGC) perfectly, as represented by the red TGC line, You are given a new transducer with an unknown frequenncy. The TGC is then adjusted to create the same image as that obtained by using the 4 MHz transducer--this new TGC setting is the purple dotted line. Is the frequency of the new transducer greater or less than 4 MHz? Why?
less than 4 MHz because the delay is deeper with the new transducer and at any point in the slope, less compensation is applied with the new transducer
You are using a 4 MHz transducer and have adjusted the time gain compensation (TGC) perfectly, as represented by the red TGC line, You are given a new transducer with an unknown frequenncy. The TGC is then adjusted to create the same image as that obtained by using the 4 MHz transducer--this new TGC setting is the green dotted line. Is the frequency of the new transducer greater or less than 4 MHz? Why?
higher than 4 MHz, because the TGC curve is shifted upward and toward the right. the delay is shallower.
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 system's compensation
Which of the following choices is best when the image on your ultrasound system is saturated (too bright everywhere)?
C. decrease the output power
Which of the following choices is best when the image of your ultrasound system displays only bright reflectors but no weak reflectors throughout the image?
B. adjust the reject level
Which of the following choices is best when the image on your ultrasound system displays only reflectors in a region close to the transducer but no reflectors that are deep?
A. adjust the systems compensation
All of the following are components of an ultrasound system except: A. transducer
B. pulser
C. alternator
D. synchronizer
E. display
F. receiver
C. alternator
This type of pulser generates a constant electrical signal in the form of a sine wave:
A. continuous wave
This type of pulser generates a single electrical spike, which ultimately creates a single sound pulse:
C. pulsed wave, single crystal
This type of pulser generates numerous electrical spikes, which ultimately create a single sound pulse:
A. pulsed wave, phased array
The acoustic power of a sound beam emitted from a transducer is determined by the ___________ of the pulser's signal.
B. voltage
All of the following are functions of the receiver except:
D. attenuation
Place these functions in the order in which the ultrasound system performs them:
A. reject
B. demodulation
C. amplificaiton
D. compression
E. compensation
C, E, D, B, A
True or False.
Amplification processes all reflected signals in a similar manner.
True
True or False.
Compensation processes all reflected signals in a similar manner.
False
What is the number of shades that can be represented by 3 bits?
8
2 X 2 X 2 = 8
What is the number of shages that can be represented by 8 bits?
256
2x2x2x2x2x2x2x2= 256
How many bits are needed to store:
10 shades of gray?
11 shades of gray?
15 shades of gray?
4 bits are required to store from 9 to 16 shades of gray
All of the following are true of ordinary cathode ray tubes except: A. it contains large vacuum tubes with a phosphor-coated screen
B. Electrons are emitted by a gun and swept across the screen by varying magnetic fields
C. There are 600 horizontal scan lines from top to bottom, painted in order from 1 to 600
D. There are 60 fields generated each second that combine into 30 frames per second
C.
a normal CRT creates images by using 525 horizontal scan lines
Which of the following correctly describes a typical television display?
C. interlaced
Which electronic component is required for grayscale imaging?
A.
All of the following are disadvantages of analog scan converters except: A. image fade
B. low-resolution image
C. image flicker
D. deterioration
B.
Which of the following scan converters will provide the best spatial resolution?
C.
Which of the following statements regarding a bit of computer memory is false?
D.
How many gray shades can be represented by a group of:
4 bits?
2 bits?
4 bits represents 16 shades
2 bits represents 4 shades
Which of the following statements regarding a pixel is false?
C.
Are the following prodecures usually pre- or postprocessing?
A. modifying a frozen image
B. read zoom
C. write zoom
D. adjusting the brightness on the CRT
E. increasing the receiver gain
A. post
B. post
C. pre
D. post
E. pre
Are the following forms of information usually digital or analog?
A. the signal from teh transducer to the receiver
B. the input signal to the digital-to-analog converter
C. the output signal from the analog-to-digital converter
D. the input signal to the analog-to-digital converter
E. the output signal from the digital-to-analog converter
F. a typical video signal
A. analog
B. digital
C. digital
D. analog
E. analog
F. analog
All of the following are characteristis of write magnification except: A. preprocessing function
B. more pixels in the region of interest
C. identical regions stored in the scan converter before and after zooming
D. it is the preferred method of image magnification
C.
What is the primary disadvantage of video tape and computer disc methods of image archiving?
C.
All of the following are advantages of PACS systems except: A. data will not deteroriate over time
B. images can be delivered to distant locations on the imaging network
C. older, archieved studies and reports can be reviewed easily
D. images have higher resolution than what appears on the systems display
D.
Author
aprilh4485
ID
116862
Card Set
Physics-Pulsed Echo Instrumentation/Displays and Image Storage
Description
Pulsed Echo Instrumentation/Displays and Image Storage
You are using a 4 MHz transducer and have adjusted the time gain compensation (TGC) perfectly, as represented by the red TGC line, You are given a new transducer with an unknown frequenncy. The TGC is then adjusted to create the same image as that obtained by using the 4 MHz transducer--this new TGC setting is the purple dotted line. Is the frequency of the new transducer greater or less than 4 MHz? Why?