Imaging Technology

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Imaging Technology

• How to View the Living Body

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X-Ray

• Plain radiographs (often called "plain Xrays")
  can be obtained using a variety of imaging
  methods, and they all require exposing the
  patient to X-Ray radiation. The image or picture
  is a shadow of the parts of the patient that
  absorb or block the X-Rays. The image is a
  "photographic negative" of the object - the
  "shadows" are white regions (where the X-rays
  were blocked by the object).  Plain radiographs
  are then interpreted by the Radiologist to make a
  diagnosis.

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X-ray Image
Hole shows presence of tumor that has eroded
skull.
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Fluoroscopy/X-Ray
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FLUOROSCOPY

• Fluoroscopy is a technique for obtaining "live"
  X-ray images of a living patient. The Radiologist
  uses a switch to control an X-Ray beam that is
  transmitted through the patient.  The X-rays then
  strike a fluorescent plate. The Radiologist can
  then watch the images "live" on a TV monitor.
  Fluoroscopy is often used to observe the
  digestive tract (Upper GI series - Barium
  Swallow, Lower GI series - Barium Enema or "BE").
  
• The colon is clearly seen on the BE (right). The
  white areas are barium (contrast) and the black
  regions are air.

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Fluoroscope Image
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Angiography

• Angiography is the name of a procedure that uses
  X-Rays to produce a picture (the "angiogram"). 
  This is an "invasive procedure, because it
  requires the injection into the patient of a
  substance that is radiopaque (absorbs X-Rays).
  This substance is commonly called a "Contrast
  Agent" or "Dye".
• Usually a very tiny tube is used to place the dye
  into a particular artery or vein. While the
  artery or vein contains this radiopaque material,
  it will block the X-Rays, and will cast a shadow
  of the injected vessels onto the X-Ray film or
  fluoroscope. This image will reveal the shape of
  the artery, and can help to diagnose an
  obstruction,blockage, or narrowing ("stenosis")

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Angiogram
Blood vessel
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How MRI Works MRI does not use radiation to
create images of your body. It takes advantage
of water molecules in your body combined with a
powerful magnetic unit and radio frequency to
obtain images. The MRI coil is used To transmit
and receive signals from your body. The
computer interprets the signals and generate
images which is transferred to a sheet of film
similar to x-ray film. The table slides into
the MRI unit. You wear ear plugs during imaging.
How MRI works?   MRI does not use radiation to
create images. It takes advantage of the water
molecules in your body combined with a powerful
magnetic unit and radio frequency to obtain
images. The body part to be examined is placed
into a device known as MRI coil, this is used to
transmit and receive signals from your body. A
computer interprets the signals into a series of
detailed images which is transferred to a sheet
of film similar to x-ray film.
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MRI
CT Contrast-enhanced
MRI
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CAT or CT Scan Computed Tomography
CT Scan is a specialized X-ray imaging
technique.  It may be performed "plain" or after
the injection of a "Contrast Agent".  CT creates
the image by using an array of individual small
X-Ray sensors and a computer. By spinning the
X-Ray source and the sensor/detectors around the
patient, data is collected from multiple angles.
A computer then processes this information to
create an image on the video screen. These images
are called "sections" or "cuts" because they
appear to resemble cross-sections of the body.
Because it does use X-Rays to form the image,
this technique has some limitations that are
similar to those for plain film radiographs.
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CT Scan Image
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Ultra-Sound
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Ultrasound Diagnostic ultrasound is the use of
high frequency sound waves to visualize
structures in the body. A transducer is used to
send sound waves into the body which are then
reflected off of internal structures. The echoes
are sent back to the same transducer where they
are changed into a picture of a structure of the
body. Besides pregnancies, ultrasound is used to
image the gallbladder, liver, kidneys, pancreas,
uterus, ovaries, prostate, testicles, thyroid and
breasts. Ultrasound can also look at the blood
flow within arteries and veins in the neck,
abdomen and legs and the valves and chambers of
your heart. Ultrasound is becoming increasingly
important in surgery as a visual aide to the
surgeon.
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Can you identify this image?
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Nuclear Medicine
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PET Nuclear Medicine
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Nuclear medicine is a medical specialty that uses
techniques to image the body and treat disease.
Nuclear medicine imaging is unique in that it
documents organ function and structure, in
contrast to diagnostic radiology, which is based
upon anatomy. It is a way to gather medical
information that may otherwise be unavailable,
require surgery, or necessitate more expensive
diagnostic tests. Nuclear medicine is used in the
diagnosis, management, treatment, and prevention
of serious disease. Nuclear medicine imaging
procedures often identify abnormalities very
early in the progression of a disease. This early
detection allows a disease to be treated early in
its course when there may be a more successful
prognosis. Nuclear medicine uses very small
amounts of radioactive materials or
radiopharmaceuticals to diagnose and and treat
disease. Radiopharmaceuticals are substances that
are attracted to specific organs, bones, or
tissues. The radiopharmaceuticals used in nuclear
medicine emit gamma rays that can be detected
externally by special types of cameras gamma or
PET cameras. These cameras work in conjunction
with computers used to form images that provide
data and information about the area of body being
imaged. The amount of radiation from a nuclear
medicine procedure is comparable to that received
during a diagnostic x-ray.