Molecular Imaging

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Molecular Imaging Positron Emission Tomography
 

• Nicholas Mulhern
• BME 281

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Molecular Imaging

• Produces Images of the body
• Allows Visualization of the cellular function
• Fine molecular changes
• understanding molecular pathways
• Allows for quantitative tests
• More objectivity to the study of Specific Areas
• Noninvasive manner
• Origins in the 1950s

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Why its important?

• Earlier and more precise Disease diagnosis
• Cancer
• Neurological
• Cardiovascular diseases
• Elucidate biochemical processes
• Track the impact of experimental drugs
• clinical trials
• Many Applications 
• Oncology, Neuroimaging, Cardiology, Pharmacology
  Small animal imaging, Musculo-skeletal imaging

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(PET) 

• Provides a three-dimensional image or picture of
  functional processes in the body
• blood flow
• other biochemical
• functions

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Biomarkers

• Injected into Patient
• tagged with a radioactive atom
• Molecule determines the function imaged
• Indicator of the Biological state
• Help image particular targets or pathways
• Chemically interact with their surroundings 
• Alter Images according to Molecular changes
• Carbon-11, Fluorine-18, Oxygen-15, or Nitrogen-13
• short decay time

positron emitting radionuclide
 Fluorodeoxyglucose (FDG)
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Gamma Ray Detector

• Flat table moves incrementally within Housing
• Circular Gamma ray detector Array  
• Donut Shaped
• Contains series of scintillation crystals
• connected to a photomultiplier tube
• Scintillation crystals
• convert the gamma rays, emitted from the patient,
  to photons of light
• Photomultiplier Tubes 
• Convert and amplify the photons to electrical
  signals

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Electrical signals

• Electrical signals are then processed by the
  computer to generate images
• The table is then moved
• process is repeated
• Time Dedication
• 60 min Resting Period
• Scan 30 minutes
• Analytical results within
• 24 hours

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Result Imaging

• Resulting in a series of thin slice images
• Region of interest
• brain, breast, liver
• These thin slice images can be assembled into a
  3D representation of the patient's body

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shows that leukemia present in the bone marrow
before treatment, left, persisted after
chemotherapy, right.
Brain scans of a healthy person (top of image)
and a person with schizophrenia (bottom)
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Today

• Few PET centers in the country
• Must be located near a particle accelerator
  device
• It produces the short-lived radioisotopes used in
  the technique
• PET/CT scanner "co-registration"
• Combines CT X-ray Scan simultaneously
• Provides Anatomic Info what the structure is
• Metabolic Inform what it is doing biochemically
• TIME Magazine as the medical invention of the
  year in 2000

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A complete body PET/ CT Fusion Image
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Sources

• http//www.rikenresearch.riken.jp/eng/frontline/64
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• http//mips.stanford.edu/grants/icmic/2010-2015/
• http//www.howstuffworks.com/nuclear-medicine1.htm
  
• http//blog.cleveland.com/medical/2009/03/is_my_ch
  emo_working_new_use_fo.html
• http//sitemaker.umich.edu/pet.chemistry/positron_
  emission_tomography
• http//www.biologyreference.com/Po-Re/Psychiatric-
  Disorders-Biology-of.htmlb