NUCMED_PRELIM

• NUCLEAR MEDICINE

  The only imaging modality that have both diagnosis and treatment
• PLDT

  PHYSIOLOGY = function

  LIGAND = radiopharmaceuticals (drugs + nuclide)

  DIAGNOSIS = determine presence or absence of disease process

  TREATMENT = therapy
• PHYSIOLOGY = function
• LIGAND = radiopharmaceuticals (drugs + nuclide)
• DIAGNOSIS = determine presence or absence of disease process
• TREATMENT = therapy
• ATOM

  It is the smallest unit of a chemical element possessing the properties of that element
• ATOM

  It rarely exists alone, and they are often combined with other atoms to form a molecule.
• “atomos” – indivisible
• Greeks – the first group of people who first thought of atomism.
• Scientists at that time thought that all matter was composed of four substances: earth, water, air, and fire
• According to them, all matter could be described as combinations of these four basic substances in various proportions, modified by four basic essences: wet, dry, hot, and cold
• DALTON ATOM (1808, John Dalton)

  English school teacher published a book summarizing his experiments, which showed that the elements could be classified according to integral values of atomic mass
• According to Dalton, an element was composed of identical atoms that reacted the same way chemically.

  For example, all oxygen atoms were alike. They looked alike, they were constructed alike, and they reacted alike.

  The physical combination of one type of atom with another was visualized as being an eye and hook affair
• THOMPSON ATOM

  Late 1890, Joseph John Thompson

  while investigating the physical properties of cathode rays (electrons), he concluded that electrons were an integral part of all atoms

  He described the atom as looking something like a plum pudding, in which the plums represented negative electric charges (electrons) and the pudding was a shapeless mass of uniform positive electrification
• RUTHERFORD EXPERIMENT

  1911 Ernest Rutherford - Through a series of ingenious experiments, he disproved Thompson’s model of the atom

  He introduced the nuclear model, which described the atom as containing a small, dense, positively charged center surrounded by a negative cloud of electrons. He called the center of the atom the nucleus.
• 1913, Niels Bohr - improved Rutherford’s description of the atom.

  • Bohr’s model was a miniature solar system in which the electrons revolved about the nucleus in prescribed orbits or energy levels.
  • Contains a small, dense, positively charged nucleus surrounded by negatively charged electrons that revolve in fixed, well-defined orbits about the nucleus
• NEUTRON

  Ø  neutral charge, heaviest

  Ø  James Chadwick

  Ø  1.675 x 10^-27 kg
• ELECTRON

  Ø  negative charge

  Ø  J.J. Thompson

  Ø  9.11 x 10^-31 kg
• PROTON

  Ø  positive charge

  Ø  Eugene Goldstein

  Ø  1.673 x 10^-27 kg
• Atomic Number - The number of protons
• Atomic Mass Number - The number of protons plus the number of neutrons in the nucleus of an atom
• RADIATION

  Energy emitted and transferred through space.
• IONIZATION

  It is the process of removing an electron from an atom.
• IONIZING RADIATION – type of radiation that can remove an orbital electron from the atom with which it interacts.
• NON-IONIZING RADIATION - series of energy waves composed of oscillating electric and magnetic fields traveling at the speed of light. This have less energy than ionizing radiation.
• EXCITATION

  Usually occurs farther away from the charged particle's trajectory than ionization.

  Excited atom will de-excite and emit a low energy ultraviolet photon
• BREMSSTRAHLUNG RADIATION

  Electromagnetic radiation that is produced when charged particles are deflected (decelerated) while traveling near an atomic nucleus
• NATURAL ENVIRONMENTAL RADIATION

  Radiation can be found in soils, in our air and water, and in us because it occurs in our natural environment, we encounter it every day through the food we eat, the water we drink, and the air we breathe
•  COSMIC –  particulate and electromagnetic radiation emitted by the sun and stars;
• SUN – largest source of cosmic rays
• TERRESTRIAL –  results from deposits of uranium, thorium, and other radionuclides in the earth
• POTASSIUM-40 – are natural metabolites. They have been with us and contribute an equal dose to each of us
• RADON – the largest source of natural environmental radiation. Radioactive gas that is produced by the natural radioactive decay of uranium which is present in trace quantities in Earth
• URANIUM – Found in nuclear power plants. Mineral coming from the earth
• NATURAL RADIATION

  ü  Concrete

  ü  Bricks

  ü  Gypsum wall board or “drywall”
• MAN MADE RADIATION

  §  Any radiation sources produced by humans.

  They may be produced for use of their radiation, or for other purposes using the processes taking place in them
• “RADIUM GIRLS”

  ü  The watch dials on which they worked were extremely small, they were instructed to use their lips to bring their paint brushes to a fine point.
• MEDICAL PROCEDURES

  Most significant contributors in man-made exposure by ionizing radiation to the public
• Wilhelm Conrad Roentgen

  →      Discovered x-rays