Test Q's

Question 1

Mechanical Index

Answer 1

estimate of max amp of pressure pulse in tissue

Question 2

FDA regulations allow mechanical index of __ to be used for all applications except ophthalmic (max __)

Answer 2

1.9, 0.23

Question 3

The reciprocal of Mega is?

Answer 3

micro

Question 4

10 mm = how many cm?

Answer 4

1 cm

Question 5

10 cm = how many decimeter?

Answer 5

1 dm

Question 6

10 dm - how many meters?

Answer 6

1 m

Question 7

10 meters = how many decameters?

Answer 7

10 decameter

Question 8

10 decameters = how many hectometers?

Answer 8

1 hm

Question 9

10 hecometers = how many km?

Answer 9

1 km

Question 10

How many Hertz is 5MHz?

Answer 10

5,000,000 Hz

Question 11

How fast does sound travel in km/s?

Answer 11

1.54 km/s

Question 12

Bunching up and relaxation of energy?

Answer 12

Compression, Rarefaction

Question 13

Complete period of rarefaction?

Answer 13

Cycle

Question 14

What is wavelength?

Answer 14

Measurement of cycle and distance

Question 15

What is the symbol for wavelength?

Answer 15

Lambda

Question 16

Units for wavelength?

Answer 16

Meters

Question 17

Wavelength is inversely related to?

Answer 17

Frequency

Question 18

What components is an ultrasound wave made up of?

Answer 18

Wavelength, amplitude, frequency, period/time

Question 19

What is the amount of signal loss due to passage of sound through media?

Answer 19

Coefficient of attenuation

Question 20

What is cumulative and implies a loss of signal?

Answer 20

Tenuation

Question 21

If the frequency of a sound beam is increased, attenuation will?

Answer 21

Increase

Question 22

What type of transducer creates focusing in two dimensions, is mechanically moved and steered, but does not electronically beam steer?

Answer 22

Annular phased array

Question 23

Does an annular array probe have a dynamic aperture?

Answer 23

Yes

Question 24

Name at least two materials used to manufacture piezoelectric crystals?

Answer 24

pzt, pvdf, quartz

Question 25

What are a few major disadvantages of mechanical transducers in color doppler imaging?

Answer 25

Increased motion artifacts due to crystals movement; blood moving slower than the speed of the moving crystal will not be detected.

Question 26

As frequency increases, the attenuation coeffecient increases. True or False?

Answer 26

True

Question 27

If the frequency decreases, what will happen to the spatial pulse link?

Answer 27

The wavelength will increase. SPL will lengthen or increase. Lower frequencies have lower SPL. Longer SPL = less resolution

Question 28

If the frequency of the transducer is doubled, what will happen to the velocity of sound?

Answer 28

Remains the same

Question 29

The conversion of sound energy to heat is called?

Answer 29

Absorption

Question 30

Does attenuation for soft tissue increase or decrease with increased tissue thickness?

Answer 30

Increase

Question 31

What is the attenuation coefficient range in clinical imaging?

Answer 31

The attenuation per centimeter for each MHZ of frequency ranges from .5 to 1.1dB

Question 32

Does the spatial pulse length increase or decrease when selecting a higher frequency?

Answer 32

Decreases

Question 33

Name the most critical, technical factor in lateral resolution.

Answer 33

Probe aperture

Question 34

The minimal reflector separation perpendicular to the sound path needed to resolve separate signals describes...

Answer 34

Lateral resolution

Question 35

The beam width is reduced, lateral resolution will...

Answer 35

Improve

Question 36

Temporal resolution is dependent on what factor?

Answer 36

Time

Question 37

To eliminate image flicker, what frame rate is necessary in a real time system?

Answer 37

>15-20 frames per second or frame rate

Question 38

How many shades of gray have the human eye perceive?

Answer 38

700-900 on average

Question 39

How many shades of gray is considered state of the art?

Answer 39

256

Question 40

What purpose does the grayscale display have?

Answer 40

Range of reflection amplitudes from white to black and subtle changes in tissue compliance.

Question 41

What does dynamic range do?

Answer 41

< > insonative energy

Question 42

What is the log measurement term for insinuative energy?

Answer 42

dB

Question 43

In the average ultrasound system, the duty factor is always

Answer 43

1

Question 44

The same system is capable of receiving sound more than what percentage of time?

Answer 44

99%

Question 45

The same system is capable of receiving sound more than what percentage of time?

Answer 45

99%

Question 46

No independently confirmed significant biological affects in mammalian tissue have been reported below what intensity?

Answer 46

100 mw/cm2 SPTA

Question 47

What maximal intensity has been reported to have no significant affects on mammalian tissue?

Answer 47

100 mw/cm2 SPTA

Question 48

What are two bio effects of diagnostic ultrasound?

Answer 48

Heat (thermal) | Cavitations (mechanical)

Question 49

What appropriate time should be used when calculating SPTA intensities of PW and CW doppler?

Answer 49

Total exposure time

Question 50

If cavitation occurs and the bubbles aren't bursting, what time of cavitation is it?

Answer 50

Stable