Ultrasound Flashcards

1
Q

What is Ultrasound

A

accoustic energy due to alternating compressing and rarefying potential

> 20Mhz, inaudible to human ears

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2
Q

How is it generated: Generator

A

electric

Oscillator circuit produces high frequency

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3
Q

How is it generated: Crystal

A

synthetic
uniform beam
Transducer

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4
Q

Transducer

A

electric to accoustic energy
reverse pizoelectric effect
creates vibration @ frequency of oscillator circuit of generator
vibrating crystals causes sound head to vibrate

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5
Q

How is it generated: sound head

A

transfers accoustic tissue

ceramic, alum, stainless steel, must match crystal (not interchangeable)

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6
Q

Applicator

A

houses crystal and sound head
held by PT
hard insulated plastic

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7
Q

Electromagnetic vs. Mechanical

A

electromagnetic- protons move along wave

mechanical- molecules bump into neighbor, propagating energy

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8
Q

Mechanical longitudinal wave

A

microstreaming

along the direction the wave travels, liquid/gases

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9
Q

Mechanical transverse wave

A

perpendicular to the direction traveled

solid

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10
Q

Spatial

A

size of transducer

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11
Q

Spatial Average Intensity

A

power/ERA= W/cm2

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12
Q

Spatial Peak Intensity

A

generally over center

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13
Q

Spatial Average Temporal Peak

A

when SAI is on

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14
Q

Spatial Average Temporal Average

A

STAPx duty cycle, measures what is delivered to tissue

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15
Q

Beam Nonuniformity Ratio

A

spatial peak intensity: spatial average intensity

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16
Q

Frequency

A
  1. 75 Mhz up to 5 cm
  2. 3 Mhz up to 2 cm

higher frequency= higher absorption

17
Q

Absorption

A

mechanical to kinetic

decibals/cm

18
Q

Absorption depends on?

A

tissue type and intensity

collagen= more absorption
more intense= more absorption

19
Q

Absorption ranking

A

(most) bone, cartilage, tendon, skin, mm, nerve, fat, blood, (least)

20
Q

Reflection

A

reflected 100% in air

0.1% with couplant

21
Q

Refraction

A

wave enters @ 1 angle, continues @ another angle

22
Q

Attenuation

A

measures decrease in intensity as wave travels through tissue

23
Q

Standing wave

A

reflected wave interact with wave in opps. direction, summation occurs, leading to pain

24
Q

Cavitation

A

formation of bubbles
compression, bubbles compress
rarefaction, bubbles expand
stable cavitation- nonthermal effects of US
unstable cavitation not used therapeutically

25
Q

Contraindications of T.U.S

A
malignancy/tumor
pregnancy
CNS tissue
recently radiated tissue
cemented joint/replacement
pacemaker
thrombophlebitis
eyes, ear, genitals
infection
active hemorraging
26
Q

Factors that affect TTR

A

rate
duration
themal conductivity
rate of perfusion of blood to tissue

27
Q

Non thermal effects of T.U.S

A

increase in: histamine, calcium, phagocytosis of macrophages, protein synthesis, cap density of ischemic tissue

tissue regeneration
wound healing
altered cell membrane
white blood cell to injured site
inc in fibroblast
vascular regeneration
28
Q

T.U.S Clinical Uses

A
CT healing
superficial wound healing
pitting edema
bone healing
spasms
pain
ROM
29
Q

Precautions

A

acute inj
growth plates
breast implants
fractures

30
Q

Velocity depends on

A

properties of medium through it travels
fastest through collegen dense tissue
slowest through air