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Nuclear Medicine

Nuclear Medicine. Spring 2009 FINAL. NM Team. Nuclear medicine MD Physicist Pharmacist Technologist Patient. Principles of NM. Uses radiopharmaceuticals for diagnosis, therapy and medical research Small amounts of radioactive material used

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Nuclear Medicine

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  1. Nuclear Medicine Spring 2009 FINAL

  2. NM Team • Nuclear medicine MD • Physicist • Pharmacist • Technologist • Patient

  3. Principles of NM • Uses radiopharmaceuticals for diagnosis, therapy and medical research • Small amounts of radioactive material used • Sometimes no more than that received in CT or fluoroscopy • Studies physiology • Rather than structural appearance

  4. Tracers • Radioactive material that can be: • Injected, ingested or inhaled • Different tracers for different body parts • organ-, tissue-, or even cell-specific • They produce gamma-ray emissions from within organ being studied • Gamma or scintillation camera transforms emissions into images • Provides information about function

  5. Modality Comparisons • PET and SPECT for physiology • X-ray measures structure, size and position of human anatomy • CT creates cross sectional images of anatomy What do all of these modalities have in common?

  6. Atom Components & Isotopes

  7. Physical Principles of NM • Radioactivity • Radiation of energy from the nucleus of atom • Can be in the form of alpha, beta particles or gamma rays from the nucleus

  8. Basic Nuclear Physics • Nuclide • Atom with a particular arrangement of protons and neutrons in the nucleus • Radionuclide • Unstable nucleus that transmutes by way of nuclear decay (return to ground state) • Decay • Is the atoms attempt to regain stability • By emission of alpha, beta and gamma radiation • Different for each type of radionuclide

  9. Half Life • Physical time it takes for a quantity of radionuclide to decrease to ½ its original activity • Radionuclides half life can range from milliseconds to years • NM radionucldies range from hours to days

  10. Nuclear Pharmacy • Radiopharmaceutical • Radionuclide • Pharmaceutical • Technetium -99 • Short ½ life of 6.04 hours • Low energy gamma photon

  11. Radiation Safety • Radiopharmaceuticals must be sterile • Prep area must have isolated ventilation • Protective measures when administering or handling • Spills must be cleaned immediately • Dosimetry devices • Hands and badges

  12. Modern Day Gamma Camera • Scintillate means: to emit light • Ionizing radiation causes certain materials to glow • Scintillation detector • Detects radiation by observing the emission of light photons emitted by the materials • PMT detect and convert light photons emitted from the crystal into and electronic signal that amplifies the original photon signal • It is then sent to be viewed

  13. Detectors

  14. Collimators • Keep scattered rays from entering the scintillation crystal • Absorbs scattered gamma rays • Resolution and sensitivity • Physical characteristics • Made of material with high atomic number • Lead

  15. Crystals • Sodium iodide Thallium • Thick layer of crystals • High energies • Decreased resolution • Thin layer of crystals • Lower energies • Increased resolution

  16. PhotomultiplierTubes • Attached to the back of the crystals • Detect and convert light photons into and electronic signal that amplifies the original photon signal • About 80-100 in a gamma camera • Light pipe • Like a focusing device

  17. Put it all Together

  18. Computer • Acquires and processes data received from camera • In a time frame • Post-processing • Adjust contrast and density • Records • Dosage • Quality control

  19. Types of Camera Systems • Single detector • Dual head • Triple head

  20. Single Head Detector

  21. Dual Head Detector

  22. Triple Head Detector

  23. Imaging Methods • Static • Whole- Body • Dynamic • SPECT • Co-registration • PET

  24. Static • Single image of a particular structure • Demonstrates radiopharmaceutical distribution • Ex: lung scans, spot bone scans images, thyroid images • Obtained in various orientations, anterior, posterior, and oblique • Low activity levels • Generally 30 seconds to five minutes

  25. Whole Body • Entire body or a large section of body • Primarily used for • Bone scans • Tumor scans • Abscess imaging • Clinical and research applications

  26. Dynamic • Timed record of distribution of radiopharmaceutical • Commonly used for • Cardiac studies • Hepatobiliary studies • Gastric emptying studies

  27. Dynamic Renogram

  28. Dynamic Venogram

  29. SPECT • Images similar to CT & MRI • thin slices through a particular organ • 360 degree rotatator heads allows for: • Coronal, planar and 3D imaging • Ex: cardiac perfusion, brain, liver and bone studies

  30. SPECT and CT combination • Merges SPECT functional testing with CT anatomic landmark images • Statistics show • 25-30% change of treatment options from what would have been done with SPECT alone

  31. PET • Resolution is 2-10 better than SPECT • Radiopharmaceuticals • Minimal alteration in homeostasis • Very small amounts used • Co-registration being done with CT & MRI • Almost all new machines are fused with a CT scanner

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