An ultrasound uses sound waves to examine organs and abnormalities inside the body. It has various clinical applications in areas like cardiology, obstetrics, and neurology. The document discusses the physical principles of ultrasound including how sound waves propagate as longitudinal waves, and how an ultrasound machine works using components like a transducer, receiver, and display to produce images. It explains techniques like Doppler effect and how ultrasounds are used in different medical specialties to diagnose conditions.

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2. Introduction
 An ultrasound is machine that uses high
frequency sound waves and their echoes to
help determine the size, shape and depth of an
abnormality.
 It allow various organs in the body to be
examined right in the doctor's office or clinic.
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3. Physical principles of
sound wave
 A wave is a repeating disturbance or movement
that transfers energy through matter or space
 Mechanical waves are waves which require a
medium.
 A medium is a form of matter through which
the wave travels (such as water, air, glass, etc.)
 Waves such as light, x-rays, and other forms of
radiation do not require a medium.
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4. They are two kinds of
mechanical waves
 Transverse
 In a transverse wave the matter in the wave
moves up and down at a right angle to the
direction of the wave
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5. They are two kinds of
mechanical waves
 Longitudinal Waves (Compression Waves)
 In a longitudinal wave the matter in the wave
moves back and forth parallel to the direction
of the wave
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6. Sound wave
 Sound is a compressional wave which travels
through the air through a series of
compressions and rarefactions.
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7. Compressio
nal
Longitudinal
wave
On a compressional
wave the area squeezed
together is called the
compression. The areas
spread out are called the
rarefaction.
The wavelength is the
distance from the center of
one compression to the
center of the next
compression.
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8. The parts of a wave
Transverse wave The crest is the highest point
on a transverse wave. The trough
is the lowest point on a
transverse wave.
The rest position of the wave is
called the node or nodal line.
The wavelength is the distance
from one point on the wave to
the next corresponding adjacent
point.
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9. Wavelength and
frequency
 Wavelength is a measure of distance, so the
units for wavelength are always distance units,
such as meter, centimeters, millimeters, etc.
 Frequency is the number of waves that pass
through a point in one second.
 The unit for frequency is waves per second or
Hertz (Hz). One Hz = One wave per second.
 Wavelength and frequency are inversely related
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10. Wavelength and
frequency
 The smaller the wavelength, the more times it
will pass through a point in one second. The
larger the wavelength, the fewer times it will
pass through a point in one second.
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11. Period
 Period is the time it takes for one full
wavelength to pass a certain point.
 Frequency is waves per second.
 Period is seconds per wave.
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T
f
period
frequency
1 1
 
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12. Speed
 A wave moving through a medium travels at a
certain speed. This is Wave Speed.
 Wave speed is usually measured in
meters/second, but may be measured using
other distance units (such as centimeters per
second).
 Wave speed is calculated as the product of a
waves frequency and wavelength.
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13. Amplitude
 The amplitude of a wave is directly related to
the energy of a wave.
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14. Amplitude
 The amplitude of a transverse wave is
determined by the height of the crest or depth
of the trough
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15. The Behavior of sound
waves
 Reflection
 When a wave bounces off an object and changes
direction, this is reflection.
 Refraction
 Is the bending of a wave as it passes from one medium
to another.
 A wave travels at different speeds in different things.
 When a wave traveling a certain speed moves into
another medium, it will either increase in speed or
decrease in speed, resulting in a change in direction
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16. Diffraction
 diffraction occurs when passing through a
small opening, they diffract and spread out as
they pass through the hole.
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17. Sound travels through
different media
 We hear sound which usually travels through
air.
 Sound travels through other media as well,
such as water and various solids.
 Sound travels different speeds in different
media.
 Sound typically travels faster in a solid that a
liquid and faster in a liquid than a gas.
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18. Sound travels through
different media
 The denser the medium,
the faster sound will
travel.
 The higher the
temperature, the faster
the particles of the
medium will move and
the faster the particles
will carry the sound.
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19. Sound intensity
 Sound intensity is the energy that the sound
wave possesses.
 The greater the intensity of sound the farther
the sound will travel and the louder the sound
will appear.
 Loudness is very closely related to intensity.
 Loudness is the human perception of the sound
intensity.
 The unit for loudness is decibels.
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20. Doppler Effect
 The Doppler effect is the apparent change in
frequency detected when the sound is moving
relative to the hearer.
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21. Principles of
instrumentation in
ultrasonography
 All ultrasound scanners consist of similar
components that perform the same key
functions.
 One of these is a transmitter that sends pulses
to the transducer, a receiver and a processor
that detects and amplifies the backscattered
energy.
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22. The Transmitter
 Although the transducer is itself the transmitter of the
ultrasound pulses into the body,
 It must be energized initially by the transmitter,
which applies precisely timed, high-amplitude
voltage to the transducer.
 The length of an ultrasound pulse is determined by
the number of alternating voltage changes applied to
the transducer.
 Transducers have a range of frequencies which they
are able to produce.
 This is known as the bandwidth.
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23. Receiver
 The receiver not only detects, but differentially
amplifies weak signals emanating from
different depths.
 Different tissue thicknesses attenuate the
ultrasound variably, and the difference in echo
strength is compensated by time gain
compensation (TGC).
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24. Time Gain Compensation
 TGC is an amplification technique to increase
ultrasound echoes from tissue interfaces that
are deeper within the body.
 This is to compensate for the increasing
attenuation of the echoes returning from these
deeper areas.
 This is one of the manual controls available to
the sonographer to achieve a more uniform
grey-scale image.
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25. Display
 The ultrasound machine use 3 types of display
A-Mode or Amplitude Mode
B-Mode (Brightness Mode)
M-Mode (Motion Mode)
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26. A-Mode
 Each pulse produces a
new a one-dimensional
display or image
 Line of information on
the display
 An uncommon display,
except in
ophthalmologic
sonography used
for precise intraocular
length measurements
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27. B-Mode (Brightness Mode)
 Basis for gray scale,
two-dimensional (2D)
imaging
 US unit tracks the position
of the transducer to place a
dot on the screen
corresponding to the
transducer position (X, Y
locations), creating a 2D
image
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28. M-Mode (Motion Mode)
 One-dimension image
used to investigate
moving structures with
respect to time
 Evaluates motion pattern
of moving structures
such as in the heart
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29. Different components of
US machine
 the following parts:
1. Transducer (probe)
The probe is the mouth and ears of the
ultrasound machine.
 In the probe, there are one or more quartz
crystals called piezoelectric crystals.
When an electric current is applied to these
crystals, they change shape rapidly.
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30. Different components of
US machine
The rapid shape changes, or vibrations, of the
crystals produce sound waves that travel
outward.
The sound waves travel into the patient being
scanned.
 The sound waves bounce back at various
intervals depending on the type of material
they pass through.
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31. Different components of
US machine
2. Central Processing Unit (CPU)
The CPU is the brain of an ultrasound machine.
The CPU is a computer that contains the
microprocessor, memory, amplifiers and power
supplies for the microprocessor and transducer
probe.
The transducer receives electrical currents from
the CPU and sends electrical pulses that are
created by returning echoes.
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32. Different components of
US machine
3. Transducer pulse controls
The operator, called the ultrasonographer,
changes the amplitude, frequency and duration
of the pulses emitted from the transducer probe
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33. Different components of
US machine
4. Display
 Displays the image from the ultrasound data
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processed by the CPU.
 This image can be either in black-and-white
or color, depending upon the model of the
ultrasound machine
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34. Different components of
US machine
5. Keyboard/Cursor
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 Ultrasound machines have a keyboard and
a cursor.
 The keyboard allows the operator to add
notes and to take measurements of the
image.
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35. Different components of
US machine
6. Disk Storage
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 The processed data and/or images can be
stored on disks.
 These disks can be hard disks, floppy disks,
compact disks (CDs), or digital video disks
(DVDs).
 Most of the time, ultrasound scans are
filled on floppy disks and stored with the
patient's medical records.
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36. Different components of
US machine
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 Printers
Most ultrasound machines have printers
which are thermal. These can be used to
capture a printed picture of the image from
the monitor.
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37. Images
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38. Clinical application of
ultrasound
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 Sonography is effective for soft tissues
imaging of many different systems
 Anesthesiology
 Ultrasound is commonly used by
anesthesiologists to guide injecting needles
when placing local anaesthetic solutions
near nerves
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39. Clinical application of
ultrasound
 Cardiology
Echocardiography is an essential tool in
cardiology, to diagnose e.g. dilatation of parts
of the heart and function of heart ventricles and
valves
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40. Clinical application of
ultrasound
 Emergency Medicine
Ultrasound has many applications in the
Emergency Department,
For ex. the focused assessment for Trauma
exam for assessing significant
hemoperitoneum.
Evaluation of right upper quadrant abdominal
pain for patients who may have gallstones or
cholecystitis
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41. Clinical application of
ultrasound
 Neonatology
For basic assessment of intracerebral structural
abnormalities, bleeds, ventriculomegaly or
hydrocephalus
For soft spots in the skull of a newborn infant
(Fontanelle) until these completely close at
about 1 year of age.
 Neurology
For assessing blood flow and stenoses in the
carotid arteries
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42. Clinical application of
ultrasound
 Gastroenterology
 In abdominal sonography, the solid organs of
the abdomen
 The pancreas, aorta, inferior vena cava, liver,
gall bladder, bile ducts, kidneys, and spleen are
imaged.
 The appendix can sometimes be seen when
inflamed (as in e.g.: appendicitis
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43. Clinical application of
ultrasound
 Obstetrics
Obstetrical sonography is commonly used
during pregnancy to check on the development
of the fetus.
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44. Clinical application of
ultrasound
 Urology
To determine, for example, the amount of fluid
retained in a patient's bladder.
In a pelvic sonogram, organs of the pelvic
region are imaged.
This includes the uterus and ovaries or urinary
bladder.
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45. Clinical application of
ultrasound
 Males are sometimes given a pelvic sonogram
to check on the health of their bladder, the
prostate, or their testicles (for example to
distinguish epididymitis from testicular
torsion).
 Musculoskeletal
Tendons, muscles, nerves, ligaments, soft
tissue masses, and bone surfaces
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46. Clinical application of
ultrasound
 Cardiovascular system
To assess patency and possible obstruction of
arteries Arterial sonography, diagnose DVT
(Thrombosonography) and determine extent
and severity of venous insufficiency
(venosonography
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47. Clinical application of
ultrasound
Gynecology
 Gynecologic sonography is used extensively:
To assess pelvic organs,
To diagnose and manage gynecologic problems
including, leiomyoma, ovarian cysts and
lesions,
To Identify ectopic Pregnancy,
To Diagnose Gynecologic Cancer
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48. Conclusion
 A basic ultrasound machine has 7 main parts:
transducer, CPU, keyboard, display, storage,
printer, and transducer control.
 Sonography is effective for soft tissues
imaging of many different systems.
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49. Conclusion
 Sound is a compressional wave which travels
through the air through a series of
compressions and rarefactions; it has different
interactions such as reflection, refraction,
doppler effect, diffraction.
 All ultrasound scanners consist of similar
components that perform the same key
functions, among them we have transmitter,
transducer, receiver and display
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50. References
 C.R.Hill, J.C.Bamber, G. R. ter Haar John Wiley &Sons
physical Principles of Medical Ultrasonics
, 2004
 K. Kirk Shung Taylor & Francis Diagnostic Ultrasound
Imaging and Blood Flow Measurements
2006
 F.A. Duck, A.C. Baker, H.C.Starritt Institute of Physics
Ultrasound in Medicine ,1997
 Principles of Medical Imaging K.K.Shung, M.B.Smith,
B.M.W. Tsui Academic Press 1992
 http://en.wikipedia.org/wiki/Gynecologic_ultrasonography
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