Intro Quiz 1 Physics Flashcards Preview

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Flashcards in Intro Quiz 1 Physics Deck (140)
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91
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"Bigness" of wave

dofference between peak and avg value of the wave

amplitude of wave

92
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force

rate of energy transfer or rate which work is preformed

power

93
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concentration of strength of a wave

Intensity = watts/cm^2

intensity

94
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distance from one peak to the next

wavelength

95
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speed wave travels through medium (avg 1540 soft tissue)

propagation speed

96
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measurement of frequency

Hertz

97
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sound below the human hearing level

Infrasound

98
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20-20kHz

Audible sound

99
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2mHz-12mHz

DMS frequency

100
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any damage to tissue

ALARA as low as reasonably achievable

Bio effects

101
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30MHz-40MHz

asses vessel walls characterize plaque morphology

transducer contained in a sheath attached to catheter

no air means high preq usable

Intravascular Ultrasound

102
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.5MHz-3MHz

beam intensity result in tissue temperature increases

4°C as deep as 5cm

increases blood flow

treats muscle spasms, tendonitis and bursitis

joint swelling

Therapeutic Ultrasound

103
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used for selective destruction of tissue volumes

cancerous lesions  in liver, kidney, breast and prostate

focusing the beam allows energy concentration on affected area while sparing surround tissue

High Intensity Focused Ultrasound

HIFU

104
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Worse in Gas

better in liquid

best in solids

Wave Propagation

105
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sound traveling pressure variation

regions of compression and rarefraction

particles vibrate back and forth

parallel to the directoin of travel

 

Sound wave propagation

106
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needs physical interaction

must have medium

longitudinal 

transverse

Mechanical Wave

107
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travel in medium or vacuum

light, heat, X-rays, gamma rays TV rays

transer of energy through a varying electrical and magnetic field

Electromagnetic Waves

108
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Pressure

Density

Temperature

particle motion

Acoustic variables

109
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concentration of force

Pascals

varies cyclically as sound wave propagates

Pressure

110
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p=mass/volume

compression increases

rarefraction decreases

non linear imaging Harmonic Imaging

units kg/m3

Density

111
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any mechanical movement produces heat

sound wave vibrate the tissue and some wave energy is lost to heat with tissue

important in Bioeffects

Celcius

Kelvin

Fahrenheit

Temperature

112
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particels of tissue being imparted with momentum and traveling into the locale of the nearest neighbors

osscillate back and forth about their original location allowing energy to propagate along the wave p[ath

particles DO NOT travel with the wave

 

Particel Motion

113
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As Low As Resonably Achievable

short scan time

low power settings

short use of color and spectral

ALARA

114
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decrease in wave amplitude due to mechanical wave interaction wiht mnedium

units dB

absorption

reflection

refraction

Attenuation

115
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conversion of energy from wave to heat within medium

as Freq increases amount of energy lost increases

 

Absorption

116
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sound wave changes direction and does not continue to travel forward

returns to source

foundtation for diagnostic ultrasound

Ultrasound based on processing these refelctions

Reflection

117
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bending of wave

change in propagation velocity when angle of incidence is other than 0

Refraction

118
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without echoes

cysts

fluid filled organs

Anechoic

119
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low level reflected signals

Hypoechoic

120
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highly echogenic tissues

moderate to high reflected signals

Hyperechoic