us physics

A mechanical wave in which particles in a medium move. Sound travels in a stright line. Sound waves are longitudinal wave

The effects of the cound wave upon the biological tissue through which it passes.

Pressure ( pascals), density (kg/cm^3), and distance (cm,mm)

Help describe the waves features

Period, frequency, amplitude, power, intensity, wavelegnth, propogation speed.

Particles move in a direction that is perpendicular (right angles) to the direction that the wave popagates.(string shakeing up/down)

particles move in the same direction that the wave propagates. (example sound).

Peaks occur at the same time and at the same location

Peaks occur at different times. (out of step)

When multiple beans arrive at same location and the waves loose their individual characteristic at that moment to combine to form a single wave

Intereferance of a pair of inphase waves results in the formation of a single wave of greater amplitude than either of its componets

Interference of a pair of out of phase waves resulting in the formation of a single wave of lesser amplitude than either of its componets.

Describe features of a sound wave

Time it takes a wave to vibrate a single cycle/ time from start of one cycle to the start of the next cycle.

untis of time: seconds, ms, hours, days

Sound source. It is not adjustible by sonographer

The number of events that occurs in a sepcific duration of time.

units per second, 1/second,hertz(per second).

Sound source/ It is not adjustible by spnpgrapher

less than 20Hz.

between 20Hz and 20kHz.

Greater than 20kHz.

Reciprocals of each other

Amplitude, power, intensity

Is the bigness of a wave.

Pressure(pascals), density(g/cm^3), particle motion(cm,inches,any)

The sound source. It is adjustible by the sonographer

If the difference between maxium and minimun values of an acoustic variable.

Is the rate of energy transfer or th rate at which work is performed

Watts

Sound source. It is adjustable by sonographer

Power is porportional to amplitude squared

The concentration of energy in a sound beam.

Intensity(W/cm^2)= power(w)/area(cm^2).

Watts/square centimeter, or W/cm^2

Sound source.It is adjustable by sonographer

Poroprtional to power and amplitude squared.

The distance or legnth of one complete cycle.

mm,meters, any other unit of legnth.

Both the source and the medium. It is not adjustable by sonographer.

1.54mm/us(wavelegnth of sound in soft tissue)/ frequency(MHz).

The distance that a sound wave travels through a medium in 1 second.

meters per second, mm/us, or any dstance divided by time

The medium in which it is traveling. It is not adjustable by sonograpger

1,540 m/s

Fastest in solids(bone, tendon, muscle), Slower in liquids( blood,liver,soft tissue), slowest in gases(fat,lung,air).

stiffness, density.

The ability of an object to resist compression. Higher stiffness faster speed.

The relative weight of a meterial. Higher the density the lower the speed.

Period, frequency, amplitude, power ,intensity. Pulse duration.PRP.PRF. Duty factor

Speed

Wavelegnth. Spatial pulse legnth.

Amplitude, power, intensity.

The actual time from the start of a pulse to the end of that pulse.

units of time, us,ms,seconds

The sound source. It is not adjustable by sonographer

pulse duration(us)= #cycles x period(us) pulse duration(us)=#cycles/frequency(MHz)

The distance that a pulse occupies in space from the start to the end of a pulse.

Units of distance, mm

Both the source and the medium. It is not adjustable by sonographer.

The time from the start of one pulse to the start of the next pulse.

time,ms.

The sound source. It is adjustable by sonographer

The number of pulses than an ultrasound system transmits into the body each second

Units of HZ or per second.

The sound source. It is adjestable by sonographer

The percentage or fraction of time that a system is transmitting a pulse.

A %.

Sound source. It is adjustable by sonographer

Refers to distance or space.

The maximun value.

The mathamatical middle

Refers to all time, transmit(pulse duration) and revieve

Refers to only to the trnasmit time only(pulse duration).

Intensity that is most revelant to tissue heating.

As sound travels in the body it weakens(attenuates

Is used to report chnges of attenuation

A method of rating numbers. Log represents the number of 10's that are multiplied to create the origional number

Means the intensity was doubled its origional value

Means the intensity has become ten times larger than its origional value.

Means the intensity has become half its origional value.

Means the intensity has become 1/10 its origional value.

The decrease in intensity, power, and amplitude as sound travels .

Path legnth and frequency of sound.

The number of decibels of attenuation that occurs when sound travels one centimeter

dB/cm

attenuation coeffieient(db/cm) x distance(cm)

one half of the frequency.

Is the distance that sound travels in a tissue that reduced the intensity of sound to one half its origional value

centimeters

the medium, the frequency of sound

is the acoustic resistance to sound traveling in a medium

density(kg/m^3 x prop. speed (m/s)

rayls, Z

Medium only.

acute(less than 90degrees), right(90degrees),obtuse(greater than 90 degrees), oblique(any other than 90degrees

oblique incidance and propogation speeds of the two media are different.

The elapsed time from pulse creation to pulse reception

depth.

for every 13us of go return time, the object creating the reflection is 1 centimeter deeper ins oft tissue. ez 13us has a depth of 1 cm and the total distance traveled would be 2cm

Imaging depth(cm) x 13us/cm.

describes the measure of detail in a image

describes the property of certain materials to create a voltage when they are mechanically deformed