SPI review

Question 1

typical values for period

Answer 1

0.06-0.5 micro sec

Question 2

typical values of frequency

Answer 2

2-15 MHz

Question 3

Amplitude can have units of:

Answer 3

pascals, grams/cm^3, cm, dB

Question 4

typical values for intensity

Answer 4

.001-100 watts/cm^2

Question 5

typical value for wavelength

Answer 5

0.1-0.8mm

Question 6

typical values for propagation speed

Answer 6

1500-1600 m/s

Question 7

equation for wavelength

Answer 7

wavelength (mm)= 1.54 (mm/micro sec)/ frequency (MHz)

Question 8

typical values for pulse duration

Answer 8

.5-3 micro sec

2-4 cycles

Question 9

pulse duration=

Answer 9

cycles in pulse x period

Question 10

typical values for PRP

Answer 10

100 micro sec to 1 msec

Question 11

typical values of PRF

Answer 11

1000 to 10000 Hz

Question 12

typical value of duty factor

Answer 12

0.1 % to 1 %

.001 to .01

Question 13

Duty factor =

Answer 13

pulse duration/ PRP

Question 14

What typ of imaging has high PRF, high duty factor, and short PRP?

Answer 14

shallow

Question 15

typical values of spatial pulse length

Answer 15

0.1 to 1 mm

Question 16

spatial pulse length=

Answer 16

number of cycles x wavelength

Question 17

what type of imaging has low PRF, low duty factor, and long PRP?

Answer 17

deep

Question 18

intensity most relevent to tissue heating?

Answer 18

SPTA

Question 19

decibles have what type of scale?

Answer 19

relative

Question 20

units for attenuation coefficient

Answer 20

dB/cm

Question 21

attenuation coefficient in soft tissue

Answer 21

.5 dB/cm/MHz

Question 22

impedance is ______ not _________.

Answer 22

calculated, not measured

Question 23

typical values for impedance

Answer 23

1,250,000 and 1,750,000 rayls

Question 24

refraction requires?

Answer 24

oblique incidence and different speeds

Question 25

snells law

Answer 25

sine (transmission angle)=prop speed 2 \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ sine (incident angle)=prop speed 1

Question 26

A property of certain materials to create a voltage when pressure is applied?

Answer 26

piezoelectric effect

Question 27

Q factor =

Answer 27

resonant freq/bandwidth

Question 28

axial resolution equation in soft tissue

Answer 28

.77 x # cycles in pulse/ freq

Question 29

A-mode

Answer 29

xaxis: depth yaxis: amplitude

Question 30

B-mode

Answer 30

xaxis: depth zaxis: brightness

Question 31

m-mode

Answer 31

xaxis: time yaxis: depth

Question 32

sector mechanical steering fixed focusing 1 crystal image loss

Answer 32

mechanical

Question 33

rectangular no steering fixed focusing 200 rectangular crystals vert line dropout

Answer 33

linear switched

Question 34

sector electronic steering fixed focusing 200 rectangular crystals poor steering and focusing

Answer 34

linear phased array

Question 35

sector mechanical steering electronic focusing 5 ring crystals horiz line dropout

Answer 35

annular phased

Question 36

blunted sector no steering fixed focusing 200 rectangular crystals vert line dropout

Answer 36

convex sequential

Question 37

blunted sector electronic steering electronic focusing 200 rectangular crystals poor steering and focusing

Answer 37

convex phased

Question 38

flat top sector electonic steering electronic focusing 200 rectangular crystals poor steering and focusing

Answer 38

vector

Question 39

frame rate is determined by what two factors?

Answer 39

speed of sound in a medium and depth of view

Question 40

what is a beam former?

Answer 40

creates the firing patterns for phased array systems

Question 41

The science of identifying and measuring those characteristics of an US field which are especially relevent to its potential for producing biological effects?

Answer 41

Dosimetry

Question 42

Mechanistic approach is cause and effect, what is the emperical approach?

Answer 42

exposure and response

Question 43

\_\_\_\_\_\_\_ beams are less likely to cause temp elevation in tissues.

Answer 43

focused

Question 44

intesity limits for unfocused sound and focused sound?

Answer 44

unfocused: 100 mW/cm^2 focused: 1000 mW/cm^2

Question 45

microbubbles get _______ during rarefractions. cavitation is more likely to occur in ______ than other tissues.

Answer 45

bigger lung

Question 46

Mechanical index is higher, more likely to produce cavitation with:

Answer 46

peak rarefraction pressure and lower frequency

Question 47

bulk modulus also means what?

Answer 47

stiffness