Physics I

Question 1

Strength of the reflected and transmitted pulses are determined by what?

Answer 1

The impedances of the two mediums at the boundary

Question 2

What is the formula for direct linear proportional relationship?

Answer 2

y = 3x

Question 2

What is the formula for indirect linear proportional relationship?

Answer 2

y = 3/x^2

Question 2

Attenuation is an example of what tpye of relationship?

Answer 2

nonlinear and exponential relationship

Question 2

What is the formula for non-linear proportionality?

Answer 2

y = x^2

Question 2

In a wave, what are compressions?

Answer 2

Areas of high pressure and density

Question 3

In a wave, what are rarefactions?

Answer 3

Low pressure and density

Question 4

What are 4 acoustic variables in a sound wave?

Answer 4

• pressure
• density
• particle motion
• temperature

Question 5

Sound wave terms:

What is frequency?

Answer 5

How often something happens, number of cycles per second
units: hertz, kilohertz, and megahertz (m/c for US)

Question 6

Sound wave terms:

What is a cycle?

Answer 6

One complete variation in pressure or acoustic variable

Question 7

Sound wave terms:

What is frequency? (f)

Answer 7

1Hz = 1 cycle per second

Number of occurrences over a repeating event

Question 8

Sound wave terms:

What is the formula for frequency?

Answer 8

propagation speed (m/s)
__________________________
wavelength (mm)

Question 9

Sound wave terms:

What is period? (T)

Answer 9

Time it takes for once cycle to occur
units: seconds, microseconds

Question 10

Sound wave terms:

What is the formula for period?

Answer 10

T (μs) = 1
_______
frequency (MhZ)

Question 11

Sound wave terms:

What is a wavelength?

Answer 11

The length of space one cycle takes up
unit: millimeter (mm)

Question 12

Sound wave terms:

What is the formula for wavelength?

Answer 12

wavelength (mm) = propagation speed (m/s)
__________________________
frequency (MHz)

Question 13

Sound wave terms:

What is propagation speed?

Answer 13

The speed at which a wave moves through a medium
unit: meter/second; millimeter/microsecond

Question 14

What is the average propagation speed in soft tissue in m/s and mm/μs?

Answer 14

1540m/s
1.54 mm/μs

Question 15

What is the bulk modulus?

Answer 15

The stiffness is the resistance to compression, also called the hardness

Question 16

What are the two periods of Pulsed Ultrasound?

Answer 16

Ringing and listening period

Question 17

What is PRF? (pulse repetition frequency)

Answer 17

Number of pulses created by the system per second

Question 18

What is PRP? (pulse repetition period)

Answer 18

Time from the start of one pulse to the start of the next
unit: milliseconds (ms)

Question 19

What is PD? (pulse duration)

Answer 19

Actual time the pulse is on
unit: microsecond (μs)

Question 20

What is Duty Factor?

Answer 20

Fraction of time that pulsed US is on

Question 21

What is spatial pulse length?

Answer 21

Length of space occupied by a pulse

Question 22

What is bandwidth?

Answer 22

Range of frequencies contained within a pulse

Question 23

PRF and PRP have a relationship - describe it.

Answer 23

If PRF decreases, PRP increases.

Question 24

What unit does PRF use?

Answer 24

- kilohertz

Question 25

Adjusting depth affects which: PRP or PRF?

Answer 25

Both!

Question 26

What controls PRP in soft tissue?

Answer 26

Depth & speed of sound

Question 27

What is the formula for Pulse Duration?

Answer 27

PD = n x T (number of cycles in the pulse x the period)

Question 28

Sonographic pulses are typically how many cycles long?

Answer 28

2 - 3 cycles

Question 29

Doppler pulses are typically how many cycles long?

Answer 29

5 - 30 cycles

Question 30

_______ pulses improve quality of US images. (shorter/longer)

Answer 30

shorter

Question 31

What is the Duty Factor formula?

Answer 31

DF = PD (μs) _____ x 100 PRP (μs)

Question 32

What is the equation for SPL?

Answer 32

SPL (mm) = wavelength (mm) x number of cycles in the pulse

Question 33

SPL _______ (increase/decrease) when # of cycles in pulse _______ (increase/decrease), SPL ________ (increases/decreases) when frequency increases.

Answer 33

increases increase decreases

Question 34

What is happening to Transducer Frequency when: Wavelength decreases Penetration Distance decreases Spatial Resolution improves

Answer 34

Frequency increases

Question 35

A higher transducer frequency = _____ (shorter/longer) wavelengths = ______ (more/less) penetration.

Answer 35

shorter less

Question 36

What is the range of ultrasound frequencies contained in a pulse called?

Answer 36

Bandwidth

Question 37

What is the bandwidth for the curvilinear probe used for abdomens?

Answer 37

1 - 6 MHz

Question 38

What is the bandwidth for the linear probe used for superficial structures?

Answer 38

2 - 9 MHz

Question 39

What is the bandwidth for the cardiac probe?

Answer 39

1 - 5 MHz

Question 40

What is the bandwidth for the ML 6-15 probe used for paeds and neonates?

Answer 40

4 - 15 MHz

Question 41

What are 2 indicators of the strength of the sound?

Answer 41

Amplitude and intensity

Question 42

What is the definition of: amplitude of sound?

Answer 42

How loud it is

Question 43

What is the definition of: power of sound?

Answer 43

The time required to transfer energy

Question 44

What is the definition of: the intensity of sound?

Answer 44

Rate at which energy passes through a unit area

Question 45

What is an acoustic variable?

Answer 45

Pressure Density Particle Motion Temperature

Question 46

What is the definition for a maximum variation that occurs in an acoustic variable?

Answer 46

Amplitude

Question 47

How is an amplitude of a pulse deteremined?

Answer 47

By how hard the crystals of the transducer are struck

Question 48

Power is the rate of what

Answer 48

The rate of energy transfer over time from one location to another (energy that travels along an ultrasound beam), measured in Watts

Question 49

If the transmit voltage (amplitude) is doubled, the power will be __________.

Answer 49

Quadrupled

Question 50

What is the formula for intensity?

Answer 50

power _______ area