Medical Imaging

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Medical Imaging

• X-ray
• Fluoroscopy
• Computerized Tomography
• (CT Scan)
• Positron Emission Tomography
• (PET Scan)
• Ultrasound
• Magnetic Resonance Imaging (MRI)
• Biophotonics

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X-RAYS
? (x-ray attenuation)
X-ray source
OPAQUE Bone, Metals, Iodinated contrast agents
Shadow
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X-Rays high energy photons

• Absorbed by denser tissues (attenuated) to
  produce a lighter image on the film (radiograph)
• Can be used to diagnose some cancers, respiratory
  and cardiovascular diseases such as enlargement
  of the heart and structure of blood vessels
• Dentists use to determine health of teeth and jaw
• The high energy radiation of x-rays can cause
  mutations to DNA

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Chest X-Ray
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X-Ray of a murder victim killed with 30 nails
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Normal Hand X-Ray
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Rheumatoid Arthritis Hand X-Ray
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Knee Joint X-Ray
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Broken Neck X-Ray
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Swollowed Scissors X-Ray
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X-Ray Photobomb...
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This is why high heels hurt your feet!
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Fluoroscopy uses a continuous beam of
X-rays to view a radioactive contrast agent

• The most commonly used x-ray dye is barium
  sulfate, a white-chalky substance.
• Fluoroscopic X-Ray images the gastro-intestinal
  system and blood vessels of the brain and heart
• Images of the opaque dye travelling through the
  arteries to locate a blockage is called an
  angiogram
• The advantage of Fluoroscopic x-ray over
  conventional x-ray is that you can view in real
  time on a television monitor the image
• This means that movement of the peristalsis and
  normal function of the body's systems can be
  captured and recorded on videotape
• Because fluoroscopy involves the use of x-rays,
  ionizing radiation, all fluoroscopic procedures
  pose some health risks.
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Barium Fluoroscopy
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Compare the image of the normal heart on the LT.
with the image on the Rt.. In the Rt. image you
see a patient with congestive heart failure whose
heart has lost its ability to pump blood
efficiently. The heart on the Rt. significantly
enlarged, a key indicator of heart failure.
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Fluoroscopy X-Ray Dog Neck and Shoulder
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Computerized Tomography (CT)
??x,y) (x-ray attenuation)
Collect projections at all angles Digital
Reconstruction on a computer
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CT SCAN uses X-rays as well

• X-rays are directed all around the patient from
  various angles to create a 3-D image of the
  tissues
• Detailed, cross-sectional images are used to
  diagnose cancer, abnormalities of skeletal tissue
  and the circulatory system
• Relatively quick and painless

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CT Scan - Heart
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CT Scan 3D of various views of the Heart
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Nuclear medicine (PET Scans)

• PET Positron Emission Tomography
• After the patient is given a radioisotope that
  emits positrons (positively charged electrons),
  PET scanning is used to detect cancer, as well as
  a number of cardiovascular and neurological
  abnormalities (such as Alzheimers and epilepsy).
• Cancer cells, for example, have a much higher
  level of metabolic activity than normal cells.
  Cancer cells therefore consume radioactive
  isotopes (such as radioactive iodine). PET
  scanning detects that increased metabolic rate
  and can therefore
• Show whether a tumor is benign (non-cancerous) or
  malignant (cancerous)
• Help doctors determine the extent of disease
• Illustrate metastatic disease (spread)
• Help doctors evaluate the effectiveness of
  chemotherapy

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PET Scan Tumours before Chemotherapy (Lt.) and
after (Rt.)
PET Scan
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PET Scan - cancer of the head and neck with
extensive metastatic disease
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PET Scans can detect metabolic changes in
different tissue types

• Certain neurological disorders have
  characteristic metabolic changes. These are
  readily apparent on PET images. Alzheimers
  disease, for example, has a unique appearance on
  PET scans. This appearance can differentiate
  Alzheimers from other forms of dementia, and
  give the patient earlier access to appropriate
  treatments.
• In cardiovascular disease, PET images provide
  information about blood flow and the presence of
  damaged muscle tissue. This information is key to
  planning appropriate treatments and disease
  management.

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PET scan images superimposed on MRI scan images
shows a healthy medical student's brain function
when performing arithmetical tasks at the same
time as being exposed to speech.
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PET Scan of the Brain of a 20 yr old man (Lt.) vs
80 yr old man (Rt.)
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Your Brain on Drugs (the red areas indicate
glucose uptake ( metabolism and brain function))
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Ultrasound
r(x,y,z) acoustic reflectivity
Propagate sound pulse and receive
reflection Compute position and velocity of
reflection (Doppler shift)
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2D
3D
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Ultrasound of a normal human uterus
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Ultrasound of Human gall bladders
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Magnetic Resonance Imaging (MRI)

• The MRI provides excellent differentiation
  between various types of soft tissues compared to
  radiographs (X-rays and CT).
• MRI can be used to visualize the brain, heart,
  liver, spinal cord, eyes, nasal cavities, inner
  ears, joints, and bones without injecting any
  contrast material.
• It is the most sensitive imaging for early
  disease detection of the above tissues and for
  cancer diagnosis.
• A functional MRI (fMRI) allows us to view the
  images in real time on a television monitor

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How the MRI works

• Uses powerful magnets and radiowaves as a
  non-invasive imaging technique with no damaging
  radiation
• These magnetic and radiowave fields influence the
  behaviour of hydrogen nuclei in water
• The behaviour of these hydrogen nuclei is
  detected and analysed by computers that generate
  detailed images of the tissues

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MRI Systems

• 2-3 million

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MRI Section through head
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MRI Cross Section of Head
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f-MRI Where in the brain is hand/eye
coordination?
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MRI Neck Region
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MRI Knee Joint
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Mammogram (X-Ray) vs MRI
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MRI of Blood Flow in the Brain
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MRI Dog Skull
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Biophotonics

• Biophotonics offers the ability to diagnose and
  monitor disease nearly at the speed of light,
  based on the way light interacts with tissue and
  is scattered by the molecules and atoms.
• With biophotonics, healthcare professionals will
  know in moments what before took hours or days
  with traditional tests, enabling treatment to
  begin immediately.
• Since normal tissue scatters light differently
  than abnormal tissues, Biophotonics also allows
  for studying human tissue at the cellular and
  molecular level for the purposes of detecting,
  diagnosing and monitoring disease.

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Exposure of chicken embryos to laser light to
detect changed in development and stages of cell
specialization/differentiation
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Imaging cerebral blood flow in mice using light
with skull left intact

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