Physics Quiz 1 Flashcards
What is the technique where multiple sound beams are emitted from the transducer from different angles to create one image?
Compound imaging
An increase in (blank) would reduce image noise.
Persistence
Assuming all of these were in use, which scan converter matrix would have the best memory spatial resolution?
8 bit
12 bit
2 bit
5 bit
12 bit
How many shades of gray is a four bit digital scan converter capable of storing?
16 shades
The process of smoothing (spatial averaging) is a technique…
Where values in the surrounding pixels are used to calculate a new value for the pixel of interest.
Which instrument component can usually handle the widest range of echo signal amplitudes?
Receiver
(Also called the signal processor)
The binary number 1001001 represents what number?
73
What technique is used to fill in missing data?
Interpolation
If there were no attenuation in tissue, what would not be needed?
Compensation
When comparing gray scale and bistable imaging systems, what does a gray scale imaging system display when not seen with a bistable system?
A range of reflection amplitudes
True/False
Dynamic range of the receiver is the ratio of the largest to smallest intensity the machine can handle.
False
(Largest to smallest AMPLITUDE)
This function in the receiver takes the negative half of a signal and turns it into a positive voltage
Rectification
What would the number 392 be represented as in the binary system?
110001000
Which zoom method improves spatial resolution?
Write magnification
True/False
Interlaced monitors yield higher frame rates than the non-interlaced monitors.
False
The maximum frame rate permitted for a 15-cm penetration depth, three focuses, and 200 scan lines per frame is approximately ____
8.5
A change of the shape of the electrical signal into a video form is termed ______________.
Demodulation
What is the term used to describe the picture elements?
Pixel
PACS stands for (blank)
Picture archiving and communications system
The ability of a gray-scale display to distinguish between echoes of slightly different intensities is called (blank)
Contract resolution
The ______ carries out filtering, detection, and compression.
Signal processor
At a distance of two near zone lengths, the beam diameter is ______ the transducer diameter
Equal to
Ultrasound transducers operate according to ______________.
The piezoelectric principle.
Axial resolution is:
The minimum reparation necessary to resolve reflectors along the scan line.
The (blank) determines how amplification is accomplished in the amplifier.
Gain control
Pixel interpolation, persistence, and panoramic imaging are examples of (blank)
Preprocessing functions
True/False
A highly compressed signal will have greater contrast resolution.
True
True/False
If the penetration is increased the PRF must be increased.
False
What is the function of compression in an ultrasound unit?
Reduce the signal amplitude differences
The advantage of the super VHS format compared with the standard VHS format is that:
Spatial detail is improved
True/False
Teleradiology is the electronic transfer of images via coaxial cables, email, or telephone lines.
False
(Images are not sent via email)
True/False:
Ultrasound images printed using a thermal processor have poorer resolution and fewer shades of gray compared to an x-ray film.
True
(Blank) is the number of complete cycles per second
Frequency
Sound requires a _____________ through which to travel
Medium
If frequency increases, period will (blank)
Decrease
Wavelength is the (blank) over which one cycle occurs
Distance
Propagation speed is the speed at which a wave (blank) through a medium
Travels
Stiffer media have (blank) sound speeds
Higher
Ultrasound pulses contain a range of frequencies called the (blank)
Bandwidth
Pulsed ultrasound consists of (blank) separated by (blank) of time
Pulses ; gaps
All of the following are acoustic variables except:
- density
- particle motion
- compression
- pressure
Compression is not an acoustic variable
