1. Rev. 9-27-2010 Please Be Courteous To Others Deactivate all cell phones and pagers at this time!

2. Rev. 9-27-2010 Properties of Ionizing Radiation Kyle Thornton RADL 70

3. Rev. 9-27-2010 Ionizing Radiation Produces positively and negatively charged particles Man-made or natural Can be particulate or electromagnetic waves https://www.youtube.co m/watch?v=K_zc1WKT 0CA https://www.youtube.co m/watch?v=K_zc1WKT 0CA

4. Rev. 9-27-2010 Picture of Alpha Particle

5. Rev. 9-27-2010 Particulate Radiation Alpha radiation  Made of four particles Two protons – two neutrons  Does not penetrate matter easily  Large/slow moving  Carries a lot of energy  Interact with matter very quickly  Could not penetrate a piece of paper  Dangerous if taken inside the body  Personnel monitoring is not normally sensitive to alpha particles

6. Rev. 9-27-2010 https://www.youtube.co m/watch?v=Lg9coTz43 K0 https://www.youtube.co m/watch?v=Lg9coTz43 K0

7. Rev. 9-27-2010 Sources of Alpha Radiation Alpha EmitterAtomic Number Americium 24195 Plutonium 23694 Uranium 23892 Thorium 23290 Radium 22688 Radon 22286 Polonium 21084

8. Rev. 9-27-2010 Sources of Alpha Radiation Uranium decays to Radium which decays to Radon  Radon is a gas, easily inspired into the body  Radon daughter (decay) products include polonium, bismuth and lead

9. Rev. 9-27-2010 Uses of Alpha Radiation Americium 241  Used to power smoke alarms by creating an electrical current Radium 226  Used to treat cancer – brachytherapy implants Polonium 210  Used as a static eliminator in paper mills and other industries

10. Rev. 9-27-2010 Particulate Radiation - Beta  Produced only in or near nucleus of an atom  Mass is about 1/2000 the size of a proton or neutron  Contains mainly high speed electrons  Behave similarly to a speeding bullet

11. Rev. 9-27-2010 Beta Particle Production Created when ratio of protons to neutrons is too high An excess neutron is converted to a proton and electron Gamma ray production often accompanies this process

12. Rev. 9-27-2010 Beta Radiation Production

13. Rev. 9-27-2010 Comparison of Particulate/Electromagnetic Energy https://www.youtube.co m/watch?v=ec8iomUS3 4U https://www.youtube.co m/watch?v=ec8iomUS3 4U

14. Rev. 9-27-2010 Sources of Beta Particles Tritium Cobalt-60 Strontium-90 Technetium-99 Iodine-129 and -131 Cesium-137

15. Rev. 9-27-2010 Uses for Beta Particles Iodine 131  Used to treat thyroid cancers and Graves disease Carbon 14  Used to date organic matter up to 30,000 years old Tritium  Used for luminous dials, i.e., wristwatches, etc

16. Rev. 9-27-2010 Electromagnetic Spectrum

17. Rev. 9-27-2010 Electromagnetic Types Of Ionizing Radiation Gamma Rays  Monoenergetic waves of energy, able to penetrate most matter  Identical to x-rays in energy, wavelength, and frequency  Produced in nucleus  Generally emitted from radioactive materials

18. Rev. 9-27-2010 Uses of Gamma Rays Cesium 137  Cancer treatment Cobalt 60  Cancer treatment  Pasteurizing food Technitium 99m  Diagnostic Imaging Studies

19. Rev. 9-27-2010 X-Rays Similar to gamma – no mass or charge  Produced outside nucleus Accelerating electrons in a vacuum Having them strike a metal target  Highest energy of all electromagnetic waves shortest wavelength, highest frequency

20. Rev. 9-27-2010 Physical Properties Of X-Rays Most penetrating electromagnetic waves They are heterogenous Polyenergetic Travel in a straight line Isotropic - Travel in different directions Affect photographic film Ionize all matter including gases Cause biologic changes

21. Rev. 9-27-2010 Physical Properties Of X-Rays Cannot be focused by a lens Do not reflect off of surfaces Electrically neutral Produce secondary and scattered radiation Cause crystals to fluoresce

22. Rev. 9-27-2010 Uses Of X-Rays Diagnostic Radiography  Fluoroscopy  Tomography  Mammography  Computed Radiography  Computed Tomography  Industrial uses  Authenticate paintings Therapeutic Radiology

23. Rev. 9-27-2010 Linear Accelerator

24. Rev. 9-27-2010 Schematic of Linear Accelerator

25. Rev. 9-27-2010 Linear Accelerator

26. Rev. 9-27-2010 Linear Accelerator Therapeutic units operate below 20 mA Times are around 1 - 60 minutes Energies are around 4 - 40 MV for x-ray beams For electron beams MeV is used Linear accelerators are used to treat neoplastic growths, physics research, and to produce radionuclides

27. Rev. 9-27-2010 Filtration and Half value layer Filtration  Used to remove low energy, long wavelength x-ray photons  Inherent in the x-ray tube itself  Filtration is added by placing aluminum, molybdenum, or rhodium plates in the x-ray beam path Half-value layer  Measures beam quality  Amount of material necessary to reduce beam to half its intensity  Reduces patient dose

28. Rev. 9-27-2010 History Of Radiation Units Somatic damage apparent shortly after Roentgen’s discovery of X-rays The need to limit exposure became apparent In order to limit exposure, a means of measurement was necessary First unit was known as skin erythema dose  This amount corresponded to a few hundred rads  Skin erythema threshold varies from person to person

29. Rev. 9-27-2010 Evolution of Radiation Units The failure of the skin erythema dose as a unit necessitated another means of measurement The Roentgen took its place as the accepted unit of x and gamma radiation Today, both the international and traditional systems are used

30. Rev. 9-27-2010 Radiation Units Roentgen - Coulombs/Kilogram – Air Kerma  Ionization in air Produced by gamma or X-rays 1 R = 2.58 X 10 (-4) C/Kg Gy a – Grays in air

31. Rev. 9-27-2010 Absorbed Dose Rad - Gray  Radiation absorbed dose Amount of energy absorbed per unit mass of the object Depends on atomic number of the tissue, mass density, and incoming photon energy  One Gray = 100 Rads  Can be used for any type of radiation  Biologic effect varies with type of radiation 1 rad of X-ray does less harm than 1 rad beta radiation

32. Rev. 9-27-2010 Occupational exposure Rem - Sievert  Radiation equivalent man  Unit of biological effect  Rem = Rad X Quality factor  Used for personnel monitoring  1 Sievert = 100 Rem

33. Rev. 9-27-2010 Radioactivity Curie - Bequerel  Measures nuclear disintegration  Not an exact measurement  Curie = 3.7 X 10 (10) disintegrations/second  Bequerel = One decay/second

34. Rev. 9-27-2010 Dose Equivalent Provides a means to calculate effective dose for different types of ionizing radiation  Protons - Charge is equal in magnitude to electron Mass is 1800 X greater  Neutrons - Electrically neutral Mass slightly higher than proton  Equal absorbed doses of these types will produce different amounts of biological damage

35. Rev. 9-27-2010 Quality Factor Used to determine dose equivalency Absorbed dose is multiplied by this factor Evaluates relative hazard associated with different types of radiation  X-rays, beta particles, gamma photons, slow moving external protons have a QF of 1  Thermal neutrons - 5  Low energy internal protons – 20  Fast neutrons, alpha particles - 20

36. Rev. 9-27-2010 Linear Energy Transfer Amount of energy transferred in a medium per unit of path length This is an average amount expressed in kiloelectron volts/micrometer Low LET radiation does not transfer much energy in matter along its path  X-rays fit in this category High LET radiation transfers a lot of energy to a small area and generally do more damage High LET radiation penetrates poorly, and poses more of a risk internally  High LET radiation has a high quality factor

37. Rev. 9-27-2010 Stochastic Effects Nonthreshold, randomly occuring biologic effects from radiation  Cancer  Genetic abnormalities

38. Rev. 9-27-2010 Non-Stochastic Effects Deterministic effects from known amounts of radiation  Blood changes  Temporary sterility