Ultrasound Basic Physics Principles

Question 1

a mathemamatical relationship whereby two phyical are related; increasing or decreasing together, and with a constant ratio

Answer 1

Directly Proportional

Question 2

Describes a relative relationship between two variables

Answer 2

Related or Proportional

Question 3

Implies an opposite relationship between two variables.

Answer 3

Inversely Proportional

Question 4

the absolute inverse of a quantity.

Answer 4

Reciprocal Relationship

Question 5

The term for sound energy travel from one thing to another through a medium

Answer 5

Acoustic Propagation Properties

Question 6

An undesired biological change to tissues as a result of interaction with the ultrasound beam (ex. heat)

Answer 6

Biologic Effects

Question 7

concentration of force, units: lb/sq inch, Pascals Pa

Answer 7

Pressure

Question 8

concentration of mass or weight, units: kg/cubic cm

Answer 8

Density

Question 9

measure of particle motion, units: cm, feet, miles

Answer 9

Distance

Question 10

A wave that oscillates perpendicular to the axis along which the wave travels.

Answer 10

Transverse Wave

Question 11

waves that molecules vibrate in the same direction as the energy travels

Answer 11

Longitudinal Wave

Question 12

Two waves with the same frequency, therefore line up everywhere

Answer 12

In-phase wave

Question 13

Waves with the same frequency but different phases

Answer 13

Out-of-phase wave

Question 14

Greater wave interference +

Answer 14

Constructive Interference

Question 15

Lesser wave interference -

Answer 15

Destructive Interference

Question 16

transducer

Answer 16

Source

Question 17

The material through which a mechanical waves propagate

Answer 17

Medium

Question 18

The time of a cycle

Answer 18

Period

Question 19

How many cycles per second

Answer 19

Frequency

Question 20

Strength of the beam

Answer 20

Amplitude

Question 21

Rate that work is performed; rate of energy transfer

Answer 21

Power

Question 22

Concentration of energy in certain areas of the sound beam

Answer 22

Intensity

Question 23

The distance of one cycle

Answer 23

Wavelength

Question 24

The speed at which the cycles travel

Answer 24

Propagation speed

Question 25

The concentration of matter (mass per unit volume)

Answer 25

Density

Question 26

The resistance of material to compression

Answer 26

Stiffness

Question 27

Collection of cycles that travel together

Answer 27

Pulsed Sound

Question 28

``` Time from the start of one pulse to the end of the pulse, # of cycles in the pulse x period or # of cycles in pulse/frequency ```

Answer 28

Pulse Duration

Question 29

The distance a pulse occupies in space from the start of one pulse to the end of the pulse, units: meter, mm, any unit of distance, # of cycles in the pulse x wavelength

Answer 29

Spatial Pulse Length

Question 30

Time from the start of one pulse to the start of the next, units: seconds, microseconds

Answer 30

Pulse Repetition Period

Question 31

Number of pulses that occur in a single second, units: Hz or per second

Answer 31

Pulse Repetition Frequency

Question 32

Percentage of time that the system is transmitting a pulse (or ‘on’ / not listening)

Answer 32

Duty Factor

Question 33

space related (physical dimension)

Answer 33

Spatial

Question 34

the highest intensity area or time of the sound beam (maximum value)

Answer 34

Peak

Question 35

take peak, low, and medium intensities and average them together to get average intensity (mean value)

Answer 35

Average

Question 36

(time related) variations

Answer 36

Temporal

Question 37

a collection of cycles that travel together

Answer 37

Pulsed

Question 38

1/10th of a Bel, Bel is a logarithmic ratio of the relative power in two acoustic beams

Answer 38

Decibel

Question 39

reduction in intensity as wave travels through a medium

Answer 39

Attenuation

Question 40

When some of the energy of the beam is reflected back to form an echo, while the remainder of the beam carries on traveling forward through the tissue

Answer 40

Reflection- Specular

Question 41

When the interface is rough and the undulations are approximately one wavelength or less then sound is reflected in all directions

Answer 41

Reflection- Diffuse

Question 42

the random redirection of sound waves in multiple directions

Answer 42

Scattering

Question 43

sound scatters symmetrically in all directions

Answer 43

Rayleigh Scattering

Question 44

Transfer of energy from the sound beam to the medium (tissue) through which it is traveling.

Answer 44

Absorption

Question 45

attenuation occurring per/cm sound travel

Answer 45

Attenuation Coefficient

Question 46

The distance the sound beam penetrates into the tissue when its intensity is reduced to half the original value

Answer 46

Half Value Layer Thickness

Question 47

a material’s resistance to sound traveling through it (unit is Rayl

Answer 47

Impedance

Question 48

Perpendicular, Orthogonal, Right Angle, Ninety Degrees (PORN) – Occurs when the sound beam strikes a boundary between 2 media at exactly 90 degrees

Answer 48

Normal Incidence

Question 49

sound beam strikes at any angle other than 90 degrees

Answer 49

Oblique Incidence

Question 50

When the beam encounters an interface between two different tissues at an oblique angle, the beam will be deviated as it travels through the tissue.

Answer 50

Refraction

Question 51

formula which gives the relationship between the angle of incidence and the angle of refraction when beam of sound passes through an interface between two tissues where the speed of sound is different

Answer 51

Snell's Law

Question 52

Relationship between round trip pulse-travel time (sound to interface and echo coming back from it), propagation speed, and distance to a reflector.

Answer 52

Range Equation

Question 53

In soft tissue, every 13 microsec of go-return time means the reflector is 1 cm deeper in the body.

Answer 53

13 Microsecond Rule