Physics Review- Waves And Formulas

Front 1

Is ultrasound a mechanical or longitudinal wave?

Back 1

Both

Hint 1

Explaination: Ultrasound is a mechanical longitudinal wave the

Front 2

_______ is a wave that requires a medium in which to travel.

Back 2

Longitudinal wave

Front 3

A longitudinal wave can not travel in a ________

Back 3

Vacum

Front 4

What is the term for the maximum speed with which an acoustic wave can move through a medium?

Back 4

Propagation speed

Front 5

What two things determine propagation speed?

Back 5

Density and stiffness

Front 6

As the stiffness increases the prop speed _______

Back 6

increases (so the stiffer an object the faster the speed)

Front 7

Density is _______ proportional to Propigation speed

Back 7

Inversly ( so they are oposite. If one goes up the other goes down)

Front 8

__________ is the oposite of stiffness

Back 8

Compressibility

Front 9

Name the 4 acoustic Variables

Back 9

1. Pressure
2. Temperature
3. Density
4. Particle Motion

Front 10

A ________wave travels parallel to the energy source

Back 10

Longitudinal Wave

Front 11

_______ is the distance a wave must travel in 1 cycle.

Back 11

Wavelenth (it is the length of 1 wave)

Front 12

What two things determind wavelength

Back 12

1. Source
2. Medium

Front 13

What is the formula for wavelength?

Back 13

prop speed
wavelenth = --------------------------
frequency

Front 14

If the frequency increases the wavelength will ________.

Back 14

decrease

Front 15

If the propagation speed increases, but the frequency remains the same, what will happen to wavelength

Back 15

It will increase

Front 16

If period increases what will happen to frequency?

Back 16

decrease

Front 17

If one number increases, and cases another number to decrease they are ______

Back 17

inversley proportional

Front 18

If one number increases and this causes another number to increase, the two numbers are ________

Back 18

directly proportional (or just proportional)

Front 19

_______ is the maximum (or biggest) variation that occurs in an accoustic variable.

Back 19

Amplitude

Front 20

What is the formula for power?

Back 20

Amplitude^2

Front 21

_________ is the rate of energy transferred.

Back 21

Power

Front 22

What is the pulse duration equal to?

Back 22

Period multiplied by the number of cycles in a pulse

Front 23

What determines the spatial pulse length?

Back 23

Source and the medium

Front 24

What happens to the pulse duration when the sonographer decreases the maximum imaging depth in an ultrasound scan?

Back 24

The time that a transducer is 'pulsing' does not change with alterations in depth of view

Front 25

What happens to pulse repetition period if the sonographer decreases the maximum imaging depth in an ultrasound scan?

Back 25

It decreases
Because as the maximum imaging depth or depth of view is decreased, the interval of time during which the ultrasound machine listens for returning echoes is diminished. As a result of this shorter listening time, the pulse repetition is shortened

Front 26

The number of pulses that are produced by the ultrasound system in one second

Back 26

PRF

Front 27

What determines the PRF

Back 27

Sound Source

Front 28

When you increase the maximum imaging depth during an exam what happens to the frequency?

Back 28

Remains unchanged

Front 29

What determines PRP

Back 29

Sound Source

Front 30

What is a typical value for the duty factor of pulsed sound wave used in diagnostic imaging?

Back 30

0.001

Front 31

What is the value of the duty cycle for continuous wave ultrasound?

Back 31

1.0 or 100%

Front 32

What happens to the duty factor when the depth of view increases?

Back 32

Decreases
it is equal to the pulse duration divided by the pulse repetition period.

Front 33

What is the formula for duty factor?

Back 33

pulse duration divided by pulse repetition

Front 34

number of cycles per second

Back 34

frequency

Front 35

used to describe the angel of transmission at an interface based on the angle of incidence and the propagation speeds of the two media

Back 35

Snell's Law

Front 36

the time taken for a pulse to occur

Back 36

pulse repetition period

Front 37

1/frequency

Back 37

period

Front 38

1/period

Back 38

frequency

Front 39

propagation speed/wavelength

Back 39

frequency

Front 40

propagation speed/frequency

Back 40

wavelength

Front 41

pulse duration =

Back 41

# of cycles x period

Front 42

formula for duty factor

Back 42

PD/PRP

Front 43

What sound wave parameters are determined by the sound source?

Back 43

Period
Frequency
Amplitude, power, intensity

Front 44

What sound wave parameters are determined by the Medium?

Back 44

Propagation Speed
Impedance

Front 45

What sound wave parameters are determined by the Sound Source and the Medium?

Back 45

Wavelength

Front 46

What pulsed sound wave parameters are determined by the Sound Source?

Back 46

Pulse Duration
Duty factor
Pulse Repetition Period
Pulse Repetition Frequency

Front 47

What pulsed sound wave parameters are determined by the Source and Medium?

Back 47

Spatial pulse length

Front 48

Spatial pulse length =

Back 48

# cycles in a pulse x wavelength

Front 49

formula for attenuation coefficient

Back 49

Frequency/2

Front 50

formula for total attentuation

Back 50

AC x path length

Front 51

List the intensities from lowest to highest

Back 51

SATA
SPTA
SAPA
SPPA
SATP
SPTP

Front 52

the minimum distance two reflectors can be, parallel to the beam, and still appear on the screen as two dots

Back 52

Axial Resolution

Front 53

LARRD

Back 53

Longitudinal
Axial
Range
Radial
Depth
akas for axial

Front 54

the ability to accurately identify reflectors that are arrange perpendicular to the ultrasound beam

Back 54

Lateral Resolution

Front 55

LATA

Back 55

Lateral
Angular
Transverse
Azimuthal
akas for lateral

Front 56

Axial resolution =

Back 56

1/2 SPL

Front 57

shapes and steers the beam on the transmit end

Back 57

beam former

Front 58

the function of the receiver that changes the brightness of the echo amplitudes to compensate for attenuation with depth

Back 58

compensation

Front 59

the function of the receiver that decreases the range of the signal amplitudes present with the machines receiver; opposite of dynamic range

Back 59

compression

Front 60

the function of the receiver that makes the signal easier to process by performing rectification and smoothing

Back 60

demodulation

Front 61

part of the beam former that controls the amount of energy in the beam pulse

Back 61

pulser

Front 62

the part of the receiver that inverts the negative voltages to positive

Back 62

rectification

Front 63

the component of the machine that processes the signals coming back from the patient

Back 63

receiver

Front 64

Directly controls the amount of power entering the patient

Back 64

pulser

Front 65

increases or decreases all echoes equally

Back 65

amplification

Front 66

adjusts brightness of echoes to correct for attentuation with depth

Back 66

compensation

Front 67

decreases the range of amplitudes present within the system (opposite of dynamic range)

Back 67

compression

Front 68

makes signal easier for system to process includes rectification and smoothing

Back 68

demodulation

Front 69

eliminates low level echoes that do not contribute to useful information on the image

Back 69

reject