intro to physics Flashcards
what is ultrasound
imaging method using high frequency sound waves to produce images of structures within the body.
what is the role of an ultrasound tech
provide interpretable images for diagnosis for radiologist
ultrasound is sound whose frequency is
above the range of human hearing
how is an ultrasound image formed
ultrasound energy is transmitted into the patients and internal structures reflect the sound and the returning echoes form the image of structure
diagnostic ultrasound uses frequencies of
greater than 1 million Hz ( 1 MHz)
ALARA
“as low as reasonably achievable” (power lowest setting)
types of transducers
linear, convex (curved), sector (phased), endovaginal
sound bouncing off structures, organs, fluid are called
echoes
anechoic/sonolucent
no internal echoes, fluid filled transmits sound easily (black) echogenic walls
echogenic/hyperechoic
echo producing structure reflects sound with a brighter intensity (white)
a structure that is cystic or fluid filled will be
sonolucent
low level echoes within a structure
hypoechoic (grey)
mass has a few low level echoes but is less echogenic than its surroundings
echopenic (white)
completely uniform in texture or composition
homogeneous
not uniform in texture or composition
heterogeneous
having the same echogenicity or brightness as the surrounding structure
isoechoic
sound beam in completely reflected or absorbed by the structure being imaged
shadowing
when the sound beam travels through fluid the echoes behind the fluid are exaggerated or brighter than the normal surrounding tissues
posterior enhancement (flashlight effect)
horizontal axis
x axis
vertical axis
y axis
two items that are not associated
ie. hair color is ______ to shoe size
unrelated
two items that are associated but have no relationship with each other
ie. Santa is ______ to Christmas
related/ proportional
two items that are related when one increases, the other increases
ie. clothing size is _________ to ones weight (LL-UR)
directly related/directly proportional
two items that are associated when one increases the other decreases.
ie. grades in school are _________to partying time.
inversely related/ inversely proportional
UL-LR
when two numbers are multiplied together and equal 1. _______ because when one increases the other decreases.
reciprocal relationship/ inverse relationship
what are the three units for numerical values?
units of length , area, volume
what are the units of length
distance or circumference : cm, feet
what are the units of volume
cm 3, feet 3
what are the units of area
cm 2, ft 2
multiply by that number means to
increase by a factor
divide by that number means to
decrease by a factor
number with a positive exponent
value greater than 10
number with a negative exponent
number less than one
number with a exponent of zero
in a number between 1 and 10
if you move the exponent to the left
the number on the exponent will me positive
if you move the exponent to the right
the number on the exponent will be negative
L - R +
standard notation
L + R -
scientific notation
period and frequency are
reciprocals, one increases the other decreases
metric system cheat
king henry died drinking cold milk
get me my nano
if its a metric prefix if the number gets larger the number must decrease
in a metric prefix if the number gets smaller the number must increase
the transducer creates ____ and its travels through _______
sound pulses , biological tissue media
waves carry what
energy
what are the different forms of waves
heat, sound, magnetic, light
sound wave is a
mechanical longitudinal wave
a sound wave needs to travel through a medium that is ______ and can be _______
compressed, rarefied
the effects of the medium upon the sound wave
acoustic propagation properties
the effects of the sound wave upon the biologic tissue 6
biologic effects
acoustic variables of sound waves
pressure, density, distance
concentration of force in an area
pressure (Pa, pascals)
concentration of mass in a volume
Density (kg/cm^3)
Measure of particle motion
Distance (cm, mm, ft, mile)
used to describe the features of the sound wave
acoustic parameters
what are the seven acoustic parameters
Power, Frequency , Amplitude, Propagation speed, Intensity, Wavelength, Period
wave that moves left to right and particles move up and down
transverse wave
particles that move in the same direction that the wave propagates
longitudinal wave
In step wave, peak and trough same time and place
in phase wave
out of step wave peak and trough different time and place
out of phase wave
the combination of multiple sound beams
interference
there are two types of interference
constructive and destructive
formation of a single wave with a bigger amplitude that either of components
constructive interphase
formation of a single wave that results in lesser amplitude than one of the waves
destructive interference
two out of phase waves are of equal amplitude
complete destructive interference cancel each other out
frequencies of waves differ both in phase and out of phase
both constructive and destructive interference
