Reflector Depth

Question 1

Shallow imaging (4)

Answer 1

Less off time
Short prp
High prf
High df

Question 2

Deep imaging (4)

Answer 2

More off time
Long prp
Short prf
Low df

Question 3

PRP and PRF are _______ of each other

Answer 3

Reciprocals

That means PRP x PRF = 1

Question 4

If the PRF is 3 Hz than the PRP would be

Answer 4

Because PRP is the reciprocal, the PRP would be 1/3 second

Question 5

Whats the speed of pulses in SOFT TISSUE

Answer 5

1.54 mm/microsecond

Question 6

How would you calculate the time it takes the beam to hit a reflector if this is all the info you’re given: the beam travels 10 centimeters before it hits the reflector

Answer 6

Well you would convert cm into mm, so 10 cm = 100mm. Knowing that time = distance / speed we would take 100mm and divide it by 1.54 mm/ms (microseconds) which would give us 65 microseconds ONE WAY. If the question asked for roundtrip you would multiply 65ms x 2 which would give you 130 microseconds to travel a total of 20 cm. This would be known as the PRP.

Question 7

In soft tissue the PRP is 13 microseconds per centimeter or 13 microseconds x depth… this is the PRP. The reciprocal, or PRF would be 1/13 MHz. ASE likes things in Hz so that would translate into 0.077 MHz which would be

Answer 7

77,000 Hz know this

Question 8

The final equation to calculate PRF (simplified) would be

Answer 8

77,000 cm/s divided by depth (cm)

Answer is in Hz :)

Question 9

Just because a NEW transducer is selected, that DOES NOT change

Answer 9

The PRP and PRF… the only thing that is affected is the imaging depth… them giving you the strength of the US beam is just fluff info

Question 10

Period is the reciprocal of

Answer 10

FREQUENCY…

Question 11

If the frequency is 12 MHz, the period would be

Answer 11

1/12…. Just divide 1 by 12 and you get 0.083 microseconds

Question 12

Wavelength is

Answer 12

The speed of sound in soft tissue divided by the frequency

Question 13

If the frequency is 12 MHz… what is the wavelength?

Answer 13

Wavelength is the speed of sound in soft tissue divided by the frequency of

So it would be 1.54 divided by 12

= 0.1283 mm

Question 14

What are the two ways in which you can calculate pulse duration

Answer 14

1. # of cycles in pulse x the period

OR

2. # of cycles in the pulse divided by the frequency

Units are microseconds

Question 15

How do you calculate the SPL?

Answer 15

It is the # of cycles x the wavelength

Answer is in mm

Question 16

How do you calculate the DF?

Answer 16

It is the pulse duration divided by the pulse repetition period

IT IS UNITLESS; answer is a %

Question 17

Intensity is inversely related to

Answer 17

Area

Question 18

When the machine is using CW, the the duty factor is

Answer 18

100%

Question 19

When talking about spatial and temporal pulse which TWO letter acronym is the strongest ?

Answer 19

TP or temporal peak

Question 20

The strongest 4 letter acronym for intensity is _________ and the weakest is _________

Answer 20

SPTP (strongest)
SATA (weakest)

SPTA - the one responsible for bioeffects

Question 21

_________ causes cavitation, or ______ (4-letter acronym)

Answer 21

Mechanical bioeffects, SPPA

Question 22

_________ causes heating bioeffects, or this 4-letter acronym

Answer 22

Thermal, SPTA