Molecular Imaging & Positron Emission Tomography Nicholas Mulhern BME 281

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 1950’s

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

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

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)

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

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

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

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)

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

A complete body PET/ CT Fusion Image

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