Nuclear medicine

• X-ray or g-ray emitting radioisotopes are injected, inhaled, or ingested
• Main source in nuclear medicine: patient
• radionuclide:

  • isotopes
  • radioactive material we use
• pharmaceutical

  • acts as a tracer
  • chosen on the basis of its preferential localization or participation in the physiologic function of a given organ
• radiopharmaceutical two components: a radionuclide and a pharmaceutical
• Most common isotopes are technetium-99, thallium-201, and iodine-131
• Detector in nuclear medicine: gamma camera with NaI scintillation crystal measures the radioactive decay of the active agent
• emitted light in the detector of nuclear medicine is read by photomultiplier tubes
• pulse arithmetic circuitry measures number and height of pulses.

  • Further, these pulses are converted to electrical signal that is subsequently processed into a grayscale image
• metabolic, chemical, or physiological interactions of the radioisotope are measured
• The radioisotope chemical is distributed according to physiological function so the image primarily represents functional information.
• since function is distributed in the physical structures, recognizable anatomical images are produced.
• nuclear medicine measures targeted specific chemical-physiologic tissue function
• nuclear medicine is a valuable diagnostic tool particularly for imaging infarcts in the cardiovascular system, perfusion, and ventilation scanning of the respiratory tract for pulmonary embolus, imaging uptake at sites of increased bone turnover as in arthritis and tumors, assessing focal nodules, and in oncologic assessment.
• nuclear medicine has high cost and PET isotopes require a cyclotron for production