Introduction to Ultrasound History of Ultrasound

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Introduction to UltrasoundHistory of Ultrasound
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DMS

• Diagnostic Medical Sonography
• An imagining tool that is used to visualize the
  soft tissue structures of the body by sending and
  receiving sound waves to and from the body
• Acoustics
• The science of engineering and the art of
  generating, propagating, and receiving sound waves

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Ultrasound Sonographer

• Ultrasound
• Sound waves above the audible hearing range, 2-20
  kHz.
• In diagnostic ultrasound we use the range of 2-10
  MHz.
• Sonographer
• Diagnostic Medical Sonographer - is a recognized
  health professional, who utilizes high frequency
  sound waves for medical diagnosis

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Sonogram Sonologist

• Sonogram
• An ultrasound examination
• Sonologist
• A licensed physician who is responsible for
  providing the medical diagnosis of the ultrasound
  exam
• This term does not refer to any particular
  medical specialty

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Sonologist

• A physician performing the technical portion of
  an ultrasound exam is functioning in the capacity
  of a sonographer and therefore should have
  technical ultrasound training in the specialty
  being performed
• 40 - Radiologists
• 60 - Other Obstetrician, Gynecologist,
  Cardiologist, Vascular Surgeons, etc.

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History of Ultrasound Technology

• 1500 - Leonardo Da Vinci
• Discovered that sound travels in waves, and
• The angle of reflection equals the angle of
  incidence

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1845 - Christian Doppler

• Formulated the Doppler Principle - the effect of
  motion is dependent on the pitch of sound
• Doppler Effect - as sound waves move so does
  their frequency
• It was not until the twentieth century that
  scientists learned how to produce ultrasound and
  put it to work, up until this time it was just a
  theory
• The Doppler Principle is used in ultrasound today
  to detect the flow of blood in vessels

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1880 - Curie Brothers

• Discovered the piezoelectric effect - when a
  ceramic crystal is placed in an alternating
  electrical field they will expand and contract
  slightly
• Reverse piezoelectricity permitted the same
  ceramic crystal to create an electrical voltage
  from the returning sound waves, hence the
  crystals were found to be useful as both
  receivers and sources of sound waves
• Ultrasound transducers have ceramic crystals in
  them and are used in ultrasound to send and
  receive sound waves

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1900s

• Early Forms of Sonar Developed
• Langevin
• Discovered that sound waves do travel in straight
  paths
• Discovered a way to use the property of echoing
  sound waves to detect underwater objects
• Because this technology was developed between
  World Wars I II his focus of study was on how
  sound affected marine life

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Langevin

• Discovered that fish died when they were
  subjected to intense sound waves
• After the titanic sunk, he directed his energy
  toward detecting icebergs and hidden reefs in the
  ocean
• His discovery was to late to be used for military
  use in W.W.I however it greatly impacted the use
  of sonar in W.W.II.
• His technology led to the discovery of detecting
  objects underwater particularly German submarines
  during W.W.II.

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1927 - Wood Loomis

• Discovered the destructive nature of ultrasound
  on biologic organisms and living tissues
• They discovered that high doses of ultrasound
  energy on the body could be just as injurious as
  x-rays and atomic radiation and in lower doses
  ultrasound could be used as a therapeutic agent

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Between W.W.I W.W.II

• Medical applications in the 20's 30's were
  virtually all therapeutic
• Industrial applications were more diagnostic in
  nature - ultrasound waves were used to detect
  flaws in materials for construction

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During W.W.II

• Development of SONAR was used extensively in the
  military context
• There were clearly resources available to those
  imaginative enough to consider using ultrasound
  as a diagnostic medical technique during the
  early 1940's and 1950's

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1947-1949 - Ludwig

• Serving at the Naval Medical Research Institute
  of Bethesda, MD. he conducted experiments to
  determine the diagnostic capacities of
  ultrasound, using exclusively A-mode presentation
  of reflected echoes
• 1949 - Ludwig worked with M.I.T. researchers and
  found that foreign bodies in tissues could be
  detected with sound waves

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1949 - John Wild

• A surgeon who thought that by using ultrasound he
  could detect tissue thickness
• Experimented with 15 MHz frequencies
• By chance his discovery demonstrated that sound
  waves could be used in the detection and
  differentiation of cancer from normal tissue
• Echoes from sections of tumorous tissue suggested
  that echoes from tumor-invaded tissue were
  distinguishable from those produced by normal
  tissue

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1949 - John Wild

• This was the first time that sound wave
  technology was being used for diagnostic
  purposes
• Developed the first B-mode ultrasound equipment
  including the transrectal and transvaginal
  scanners and the first breast scanning equipment
• It was determined that sound travels through
  tissue at approximately 1540 cm/sec

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1950's-960's - Douglas Howry

• Used frequencies of 2-5 MHz
• Found that with these lower frequencies one could
  increase the penetration depth of the sound beam
  through tissue, however the resolution was
  reduced
• His interest was in achieving accurate anatomical
  pictures of soft tissue structures and improving
  the imaging quality at lower frequencies
• Recorded the first cross-sectional pictures
  obtained with ultrasound a 35 mm camera

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1950's-960's - Douglas Howry

• Introduced a multi-position, or also called a
  compound scanning ultrasound machine that could
  eliminate false echoes and produce better
  images
• Developed an immersion tank ultrasound system
  that could image an object that was immersed
  under water by having a transducer that would
  rotate around that object
• However ill patients could not be immersed for
  the long periods of time, which is what it took
  to get the images

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Howry Holmes

• Developed the first compound contact scanner
  which could produce one dimensional images
• focus was on teaching practitioners to use
  accurate cross-sectional anatomical imaging as
  the basis of their medical diagnosis

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1950-1960-s

• Pioneering researchers within various medical
  specialties began applying ultrasound to
  diagnostics in the early 1950s
• By the 1960s ultrasound diagnosis had been
  introduce into many medical specialties
  neurology, cardiology, gynecology, obstetrics,
  ophthalmology, and internal medicine
• The commercial development of ultrasound
  equipment intended specifically for medical
  diagnosis began during the early 1960s.

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1950-1960s - Hertz Elder

• Developed M-mode which stands for motion display
• M-mode demonstrated the use of A-mode and B-mode
  techniques together
• They used B-mode to project the echo information
  as a bright dot on the oscilloscope screen, the
  dot would move as the echo from the moving
  structure shifted position
• They then employed a continuous moving film and
  special camera to display in wave form (A-mode)
  the motion of the echo dot reflected from the
  heart

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1970-1990s

• Two dimensional imaging was perfected
• New transducers were developed
• The introduction of computer technology has made
  ultrasound equipment high tech
• Software programs have been written specifically
  for ultrasound
• Power imaging was introduced
• Three dimensional ultrasound is being used
• Contrast agents have been introduced to help in
  the therapeutic uses of ultrasound
• Ultrasound today is different than it was last
  year will continue to change as we know it

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2000

• Marked the 30th anniversary of diagnostic medical
  sonographers
• Marked the 22nd year of the Society of Diagnostic
  Medical Sonographers