What is Radiation? 2 What is Radiation?


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  • What is Radiation?
    Radioactivity is a natural and spontaneous process by which the unstable atoms of an element emit or radiate excess energy.
    Radiation is the result of the emission of excess energy.
    Explain the decay process in simple terms. Use your discretion to decide the depth for the audience.
    Alpha decay is illustrated on this slide and Beta and Gamma on the following slide
  • The depth you explain can be dependent on your age group and experience.
    Use the attached reference sheet for sites with more in depth information.
  • This slide just shows the different penetration abilities of the three decay products discussed in the previous two slides. Explanations can be modified for age group or comprehension level of the class participants.
    The point here is that these particles or waves can cause damage, but can also be prevented from damaging if shielded.
  • This slide shows the energy broken up to separate ionizing and non-ionizing radiation explain that we will use the term radiation to refer to the ionizing type for this discussion.
  • This slide allows us to discuss radiation in terms of all energy and equate it to wavelength and energy. The next slide deals with the distinction between ionizing and non-ionizing radiation
  • How to Detect Radiation
    Geiger counter
    Senses extremely tiny electrical impulses caused by radiation
    You can measure these electrical impulses with a small instrument or a large portal monitor. Show the student a Geiger counter. Demonstrate how it works by using the Geiger counter to read the radiation level of some common material. An optimal activity is to tell students you have hidden sources in the room. Ask for one volunteer to find the first source using the Geiger counter. Continue this for multiple sources if time permits.
  • We protect ourselves from radiation exposure by: Time – Distance – Shielding
    How do we protect ourselves from radiation exposure?
    OPTIONAL (TIME DEPENDENT ACTIVITY) Use a piece of paper, aluminum foil, lead plate, to demonstrate shielding effects. This ties to slide 9 with the demonstration of decay and the penetration abilities of certain types of radiation.
    We reduce exposure by limiting the time we are exposed
    We reduce exposure by increasing the distance from the source
    The more ways we protect ourselves the better.
  • Ionizing radiation procedures
    In x-ray procedures, x rays pass through the body to form pictures on film or on a computer or
    television monitor, which are viewed by a radiologist. If you have an x-ray test, it will be
    performed with a standard x-ray machine or with a more sophisticated x-ray machine called a CT or CAT scan machine.
    Typical Effective Radiation Dose from Diagnostic X Ray—Single Exposure Exam Effective Dose mSv (mrem)1
    Chest (LAT) 0.04 (4)Mammogram (four views) 0.7 (70)
    Chest (AP) 0.02 (2)Dental (lateral) 0.02 (2)
    Skull (AP) 0.03 (3)Dental (panoramic) 0.09 (9)
    Skull (Lat) 0.01 (1)DEXA (whole body) 0.0004 (0.04)
    Pelvis (AP) 0.7 (70)Hip 0.8 (80)
    Thoracic Spine (AP) 0.4 (40)Hand or Foot 0.005 (0.5)
    Lumbar Spine (AP) 0.7 (70)Abdomen 1.2 (120)
    • In nuclear medicine procedures, a very small amount of radioactive material is inhaled, injected, or swallowed by the patient. If you have a nuclear medicine exam, a special camera will be used to detect energy given off by the radioactive material in your body and form a picture of your organs and their function on a computer monitor. A nuclear medicine physician views these pictures. The radioactive material typically disappears from your body within a few hours or days.
    Exam Effective Dose mSv (mrem)2
    The following shows the dose a patient could receive if undergoing an entire procedure. For
    example, a lumbar spine series usually consists of five x-ray exams. CT stands for computed tomography
    and is sometimes called a CAT scan.
    Complete Exams Effective Dose
    mSv (mrem) 1
    Intravenous Pyelogram (kidneys, 6 films) 2.5 (250)
    Barium Swallow (24 images, 106 sec. fluoroscopy) 1.5 (150)
    Barium Enema (10 images, 137 sec. fluoroscopy) 7.0 (700)
    CT Head 2.0 (200)
    CT Chest 8.0 (800)
    CT Abdomen 10.0 (1,000)
    CT Pelvis 10.0 (1,000)
    Angioplasty (heart study) 7.5 (750) - 57.0 (5,700)3
    Coronary Angiogram 4.6 (460) - 15.8 (1,580)3
  • Museums rely on radioactive materials to verify authenticity of fossils, paintings and art objects
  • Smoke detectors – rely on tiny radioactive source to sound an alarm
    Food sterilization and preservation
    Let the students see the extent to which radioactivity is used in positive ways
    Criminology – radiation, tests can detect the toxic element arsenic in a single hair
    Automobiles – test the quality of steel and integrity of welds in vehicles
    Manufacturers – obtain the proper thickness of tin and aluminum
    Construction crews – gauge the density of road surfaces
    Sterilization – Radiation sterilizes cosmetics, hair products, contact lens solutions
  • Wind energy is one of the renewable sources of energy.
    It is considered renewable because it is ultimately derived from the sun and is capable of being replenished on a reasonable time-scale.
    If asked about zero emissions: Although wind is a zero emissions electrical generation option, there are emissions in the development and construction of wind projects – concrete, transportation of components, etc.
  • Wind is a form of renewable energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetation. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.
  • What is Radiation? 2 What is Radiation?

    1. 1. What is Radiation?
    2. 2. 2 What is Radiation? • Radioactivity is a natural and spontaneous process by which the unstable atoms of an element emit or radiate excess energy • Radiation is the result • Alpha Decay - Alpha decay occurs when the nucleus spontaneously ejects an ά particle. An ά particle is really 2 protons and 2 neutrons, or an Helium nucleus. Alpha Decay of a Uranium-238 Nucleus Parent Nucleus U238 92 Decay Event Daughter Nucleus Emitted α Particle Th234 90 He4 2 Key Proton Neutron
    3. 3. 3 Decay Products • Beta Decay - An excess of neutrons in an atom's nucleus will make it unstable, and a neutron is converted into a proton to change this ratio. During this process, a ß particle is released, • Gamma ray emission usually occurs with ά and ß emission. Gamma rays have no charge or mass, so their emission doesn't change the chemical composition of the atom. Instead, it results in a loss of radiant energy. Gamma ray emission occurs because the nucleus is often unstable after ά and ß decay.
    4. 4. 4 Decay Product Penetration
    5. 5. Ionizing radiation Energy in the form of waves or particles that has enough force to remove electrons from atoms. 5
    6. 6. Energy Spectrum 6
    7. 7. Sources of Radiation 7 Cosmic 8% Terrestrial 8% Internal 11% Radon 55% Other 1% Medical 14% Consumer Products 3% Man Made Radiation Sources – 18% • Medical X Rays • Nuclear Medicine • Consumer Products • Other Natural Radiation Sources – 82% • Radon • Internal • Terrestrial • Cosmic Data is U.S. Based National Council on Radiation Protection and Measurements (NCRP) Report No. 93, “Ionizing Radiation Exposure of the Population of the United States, “ 1987
    8. 8. •Geiger counter –Senses extremely tiny electrical impulses caused by radiation How to Detect Radiation 8
    9. 9. 9 We Protect Ourselves from Radiation Exposure by: Reducing Exposure TIME Increasing DISTANCE SHIELDING
    10. 10. Beneficial Uses of Radiation 10 Ionizing X-Ray CT Scan – Computer Tomography Nuclear Medicine Non-Ionizing Ultrasound MRI – Magnetic Resonance Imaging Medical Procedures
    11. 11. Museums and archeologists rely on radiation detection to verify the authenticity or age of art objects or archeological finds. Beneficial Uses of Radiation 11
    12. 12. •Smoke detectors – rely on a tiny radioactive source to sound an alarm when smoke is present •Food sterilization and preservation Beneficial Uses of Radiation 12
    13. 13. • Living cells and tissue are made of molecules composed of atoms united by chemical bonds • Composition of these atoms and how they bond determines the physical structure (shape) of molecules. • It is the shape of these large molecules (proteins, nucleic acids, lipids, and carbohydrates) which determines how the molecules function • Ionizing energy is powerful enough to alter the structure of atoms or molecules, the bonds involved, and greatly affect the function of the molecules in the cell and living tissue. • Altering the shape of molecules in a somatic cell can change the behavior of that cell. •Altering the shape of molecules (especially DNA) in germ cells (egg or sperm) can greatly effect the offspring of the organism. Structure and Function of Living Cells
    14. 14. Molecules of living cells: Proteins: Large molecule • Structural Component of the cell. • Function as Enzymes to control Metabolic reactions. • Important component of the cell membrane • How the atoms are connected to each causes folding of proteins into 3-D molecule. • This folding of proteins enhances and supports their function within the cell. Nucleic Acids: Also a large molecule • Double Helix shape with hydrogen bonding of the nitrogen bases in the center. • Contains the genetic material of the cell -- the cells’ instructional sheet. • Responsible for the production of proteins at the ribosomes -- by being blueprint of how to build them.
    15. 15. Effect Of Radiation on Structure of DNA
    16. 16. Direct Or Indirect Action • Direct Action - when ionized energy strikes a molecule, DNA directly • Indirect Action - strikes another molecule such as water -- a “free radical” is produced • Free Radicals react strongly to restore their stable configuration which could create other free radicals within the cell.
    17. 17. Living Cells Options after Irradiation