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| What are parameters of a sound wave? |
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Definition
| Parameters describe features of a sound wave |
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Term
| How many parameters are there for sound wave? |
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Definition
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| What are the 7 parameters of sound wave? |
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Definition
Period
Frequency
amplitude
power
intensity
wavelenght
speed |
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Term
| What is the source of the sound wave? |
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Definition
| the ultrasound system and the transducer |
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Term
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Definition
| Period is the time it takes a wave to vibrate a single cycle, or the time from the start of a cycle to the start of the next cycle |
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Term
| What is the unit of period? |
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Definition
| Period is reported in units of time, such as seconds, ms, hours, or days |
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Term
| What is the value of a period in diagnostic ultrasound? |
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Definition
1 X 10^-7 to 5 X 10^-7 seconds
0.1 to 0.5 microseconds
0.0000001 to 0.0000005 seconds |
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Term
| What is period determined by? |
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Definition
| Period is determined by the sound source only, not by the medium |
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Definition
| No the sonographer can't change the period |
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Definition
| Frequency is the number of particular events that occurs in a speicfic duration of time |
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Term
| In ultrasound how is frequency of a wave described? |
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Definition
| as the number of cycles hat occurs in one second |
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Term
| How is frequency reported in units? |
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Definition
Frequency is reported in units of per secon, 1/second, hertz or Hz
Hertz is another way to say "per second" |
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| Frequency ranges approximately from ___ MHz to _____ MHz |
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Definition
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Term
| What is frequency of a sound wave determinded by? |
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Definition
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Term
| Can frequency be adjusted? |
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Definition
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Term
| What is infrasonic sound waves? |
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Definition
| The frequency is a sound wave is less than 20 Hz. |
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Term
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Definition
| between 20 Hz and 20,000 Hz |
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Term
| What is ultrasonic sound waves? |
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Definition
| Frequency of sound wave is 20,000 Hz or more |
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Term
| Why is frequency important in diagnostic sonography? |
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Definition
| Frequency is improtant because it effects penetration and image quality |
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Term
| What is the relationship between period and frequency? |
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Definition
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Term
| What happens when period and frequency are multiplied? |
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Definition
| their product is 1 or they are reciprocal |
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Term
| What are the 3 bigness parameters? |
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Definition
amplitude
power
intensity |
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Term
| What changes the bigness parameters? |
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Definition
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Term
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Definition
It is the difference between the maximum value of a wave and the average or undisturbed value of an acoustic variable
It is also the difference between the minimum value and the average vaue of the acoustic variable |
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Term
| What is the units of amplitude? |
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Definition
Amplitude can have units of any of the acoustic variables
pressure - pascals
density - g/cm^3
partical motion - cm, inches any distance
it can also be expressed in decibels |
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Term
| What is amplitude determined by? |
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Definition
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Term
| What happens to the amplitude when sound propagates through the body? |
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Definition
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Term
| The rate at which amplitude decreases as sound propagates depends on what? |
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Definition
| on the characteristics of both the sound wave and the medium |
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Term
| Can amplitude be adjusted? |
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Definition
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Term
| What is the difference between amplitude and peak to peak amplitude? |
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Definition
Amplitude is measured from the middle value to the maximum value
Peak to peak amplitude is the difference between maximum and minimum values of an acoustic variable. Hence it is twice the value of the amplitude |
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Term
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Definition
| Power is the rae of energy transfered or the rate at which work is performed |
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Term
| What is the unit of power? |
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Definition
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Term
| What determines power initially? Then what happens? |
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Definition
Initially, power is determined only by the sound source, the ultrasound system
Power decreases as sound propagates through the body |
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Term
| What determines the rate at which power decreases as sound propagates? |
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Definition
| it depends on the characterisics of the medium and the wave |
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Definition
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Term
| How is power and amplitude related? |
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Definition
directly related
power is proportional to the wave's amplitude2 |
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Term
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Definition
| intensity is the concentration of energy in a sound beam |
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Term
| what does the intensity relate to? |
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Definition
how the power in a wave spreads or is disributed in space
Therefore intensity depends on both the power in the beam and the area over which the power is applied |
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Term
| What is the unit of intensity? |
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Definition
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Term
| what is intensity determined? |
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Definition
| intensity is determined only by the sound source, the ultrasound system |
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Term
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Definition
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Term
| What describes the magnitude or strength og a wave? |
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Definition
Amplitude
power
intensity |
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Term
| how is amplitude, power and intensity related? |
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Definition
they all are directly related
hence when intensity increases the amplitude and power also increase |
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Term
| how is intensity related to power and amplitude |
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Definition
intensity is proportional to power
intensity is proportional to the wave's amplitude seared |
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Term
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Definition
| Wavelength is the distance or length of one complete cycle |
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Term
| what are the units of wavelength? |
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Definition
| mm, meters, or any other unit of length |
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Term
| What is the typical value of wavelength in soft tissue? |
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Definition
| ranges from 0.15 to 0.8 mm |
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Term
| What determines the wavelength? |
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Definition
| both the source and the medium |
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Term
| can wavelength be adjusted |
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Definition
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Term
| What is the relationship between wavelength and frequency? |
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Definition
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Term
| what is the wavelength of 1MHz sound in soft tissue? |
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Definition
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Term
| What is the rule that defines the relationship between frequency and wavelength of sound in soft tissue? |
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Definition
| To find the wavelength of a sound wave in soft tissue divide 1.54 mm by the frequency in MHz |
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Term
| To get higher quality images with greater detail the wavelength must be - |
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Definition
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Term
| What is propogation speed? |
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Definition
| propogation speed is the distance that a sound wavae travels through a medium in 1 second |
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Term
| What is the units of speed? |
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Definition
m/s
any distance divided by time |
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Term
| What is the typical value of speed of sound |
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Definition
| ranges from 500 m/s to 4000m/s depending on the tissue through which it is travelling |
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Definition
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Definition
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Term
| What is the speed of sound in soft tissue? |
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Definition
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Term
| What is the speed of sound in lung? |
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Definition
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Term
| what is the speed of sound in bone |
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Definition
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Term
| What is the order of tissue how sound travels? |
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Definition
| lung, fat, soft tissue, liver, blood, muscle, tendon and bone |
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Term
| What is the speed of sound in air? |
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Definition
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Term
| what is the speed of sound in water? |
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Definition
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Term
| what the speed of sound in metals |
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Definition
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Term
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Definition
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Term
| what is the 2 characeristics of a medium that determin the speed of sound? |
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Definition
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Term
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Definition
| stiffness describes the ability of an object to resist compression |
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Term
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Definition
| density describes the relative weight of the material |
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Term
| how is stiffness and speed related |
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Definition
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Term
| how is speed and density related |
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Definition
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