4589708
Descripción
Mapa Mental por Jack Willepotte, actualizado hace más de 1 año
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Creado por Jack Willepotte
hace casi 9 años
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Ultrasound
- sound with a higher frequency
than what humans can hear
(above 20,000 Hz)
- Specific electrical systems can
produce electrical oscillations of any
frequency these can then be
converted into mechanical vibrations
to produce sound waves with a
frequency above 20,000Hz, ultrasound
- Specific electrical systems can
produce electrical oscillations of any
frequency these can then be
converted into mechanical vibrations
to produce sound waves with a
frequency above 20,000Hz, ultrasound
- ultrasound waves get partially
reflected and refracted at a
boundary between media
- when a wave passes into different
media some of the wave is reflected
off the two medias boundary and
some is is sent through the media
and refracted, so partial reflection
- this means a pulse of ultrasound
can be pointed at an object and
wherever there are boundaries
between two medias some of the
ultrasound gets reflected back
- time taken for the
reflections to reach a
detector measure how far
away the boundary is
- this is how
ultrasound
imaging works
- finding distance between boundaries
may be required so this is the formula:
distance(m)=speed(m/s)*T(s)
- this is how
ultrasound
imaging works
- time taken for the
reflections to reach a
detector measure how far
away the boundary is
- this means a pulse of ultrasound
can be pointed at an object and
wherever there are boundaries
between two medias some of the
ultrasound gets reflected back
- when a wave passes into different
media some of the wave is reflected
off the two medias boundary and
some is is sent through the media
and refracted, so partial reflection
- USES
- ultrasound can be widely used in
medicine from investigating blood flow
in organs to diagnosing heart problems
- ultrasound can be used to break down
kidney stones, kidney stones are hard
masses which can block the urinary tract
an ultrasound beam concentrates high
energy waves at the kidney stone turning
it into sand like particles which exit the
body through urine its good as no surgery
is needed and relatively painless
- scanning of a foetus, ultrasound waves
pass through the body however reflect
and refact at boundaries (e.g boundary
between fluid in womb and skin of
fetus) some of the wave is reflected
back and detected the timing and
ditribution of these echoes are
processed by a computer to produce an
image of the fetus
- safety,
issues and
comprimises
- safety: ultrasound waves are non-ionising and safe compared to x-rays
which are ionising and very dangerous to a developing fetus as they cause
cancer in high doses. CT scans use allot more x-ray radiation than standard
x-rays so patient is exposed to even more ionising radiation, generally CT
scans arent used unless necessary due to the increased radiation dose
- image quality: ultrasound images are typically
fuzzy so it's harder to diagnose some conditions,
then x-rays produce good images of bone and
metal but not much else however CT scans
produce very detailed images making diagnoses
easy as they produce high resoloution images, 3D
images can be used to plan complicated surgery
- safety: ultrasound waves are non-ionising and safe compared to x-rays
which are ionising and very dangerous to a developing fetus as they cause
cancer in high doses. CT scans use allot more x-ray radiation than standard
x-rays so patient is exposed to even more ionising radiation, generally CT
scans arent used unless necessary due to the increased radiation dose
- ultrasound can be used to break down
kidney stones, kidney stones are hard
masses which can block the urinary tract
an ultrasound beam concentrates high
energy waves at the kidney stone turning
it into sand like particles which exit the
body through urine its good as no surgery
is needed and relatively painless
- ultrasound can be widely used in
medicine from investigating blood flow
in organs to diagnosing heart problems
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