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PRACTICAL RADIATION PHYSICS FOR EMERGENCY MEDICAL PERSONNEL

PRACTICAL RADIATION PHYSICS FOR EMERGENCY MEDICAL PERSONNEL. Module III. What is radiation?. Ionizing radiation. Electromagnetic r adiation. IONIZING RADIATON. VISIBLE. X-RAYS. COSMIC. MICROVAVES. INFRARED. ULTRAVIOLET. GAMMA. TV, RADIO. Decreasing wave length.

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PRACTICAL RADIATION PHYSICS FOR EMERGENCY MEDICAL PERSONNEL

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  1. PRACTICAL RADIATION PHYSICSFOR EMERGENCY MEDICAL PERSONNEL Module III

  2. What is radiation? Module III

  3. Ionizing radiation Module III

  4. Electromagnetic radiation IONIZING RADIATON VISIBLE X-RAYS COSMIC MICROVAVES INFRARED ULTRAVIOLET GAMMA TV, RADIO Decreasing wave length Increasing frequency Increasingphoton energy Module III

  5. Forms of ionizing radiation Directly ionizing Particulate radiation • consisting of atomic or subatomic particles (electrons, protons, etc.) which carry energy in the form ofkinetic energy of mass in motion Indirectly ionizing Electromagnetic radiation • in which energy is carried by • oscillating electrical and magneticfields travelling through space atspeed of light Module III

  6. Origin of radiation What is the relationship between atom structure and radiation production? Module III

  7. Atom anatomy Proton Neutron Electron Nucleons Module III

  8. Isotopes Module III

  9. Why are some nuclides radioactive?Neutron to proton ratio Module III

  10. Half-life Module III

  11. Activity • The number of decaying nuclei per unit of time • The Systéme International (SI) unit of radioactivity is theBecquerel (Bq) • One Bq = 1 disintegration per second • Non-SI unit of radioactivity is theCurie (Ci) • One Ci = 3,7 x 1010 transformations per second • One milicurie (mCi) = 3,7 x 107 s-1 • One microcurie (μCi) = 3.7 x 104 s-1 • 1 Bq = 2.7 x 10-11 Ci Module III

  12. Atomic symbols MASS NUMBER (the number of protons and neutrons) A XN SYMBOL OF ELEMENT Z The number of neutrons ATOMIC NUMBER (the number of protons) Example: 131 53I78 131I or I-131 Module III

  13. Mass-energy relationship Measured Mass Calculated Mass E= mc2 Module III

  14. Fission Module III

  15. Nuclear reaction and energy production Module III

  16. Mechanisms of radioactive decay Module III

  17. Alpha (α++) decay AZX A-4Z-2Y + 42He e.g. 23892U 23490Th + 42He Module III

  18. Beta (-) decay n p + e- + υ AZXAZ+1 Y +e- + e.g. 13153I13154Xe+e-+ Module III

  19. Positron (+) decay p n + e+ + υ AZXAZ-1 Y+e++ e.g. 189F188O+e++ Module III

  20. Electron capture p+ + e-n +  AZXAZ-1 Y + 12553 I 12552 Te+ Module III

  21. Gamma () emission Module III

  22. Nuclear energy levels:gamma radiation SIMPLIFIED NUCLEAR MODEL Gammaray Module III

  23. How does radiation interact with matter? Module III

  24. Excitation Module III

  25. Ionization Electron removal by ionization Module III

  26. Alpha particle interaction Module III

  27. Interaction of alpha radiation with living matter: external deposition • Alpha radiation is not external hazard. • The maximum range in tissue is <0.1 mm • All alpha radiation is absorbed in stratum corneum Module III

  28. Interaction of alpha radiation with living matter: internal deposition Prime danger is inhalation and ingestion of alpha emitter Module III

  29. Beta interaction with matter Module III

  30. Interaction of beta radiation with living matter Cell nucleus Cell diameter 100 cell diameter alpha 1.7 MeV beta 0.15 MeV beta beta 5.3 MeV alpha Auger I I I I I ı 0.001 0.01 0.1 1 10 100 mm Module III

  31. Positron interaction:annihilation reaction Module III

  32. Neutron interaction Module III

  33. Neutron activation Module III

  34. Interaction of gamma radiation with matter • In terms of ionization, gamma radiation interacts with matter in three main ways 1. Photoelectric effect 2. Compton scattering 3. Pair production Module III

  35. Gamma interaction by photoelectric effect Module III

  36. Gamma interaction by Compton scattering Module III

  37. Pair production Module III

  38. Extranuclear energy release • Bremsstrahlung radiation • Characteristic X rays • Auger electrons Module III

  39. Bremsstrahlung radiation Module III

  40. Importance of bremsstrahlung Xrays in radiation safety practice Module III

  41. Characteristic X rays Module III

  42. Differencebetween X rays and gamma rays Module III

  43. Internal conversion:Auger electrons Module III

  44. Specific ionization andlinear energy transfer (LET) Module III

  45. Penetrating power of radiation Module III

  46. Review points • Characteristics of representative types of ionizing radiation • particulate, charged, and directly ionizing radiation of alpha and beta particles • particulate, uncharged, and indirectly ionizing radiation of neutrons • electromagnetic, uncharged, and indirectly ionizing radiation of gamma rays and X rays. • Radiation interacts with matter via two main processes: ionization and excitation • Energy, which comes in many forms, can be converted from one form to another • Nuclear potential energy is converted into kinetic energy through nuclear fission • Conversion of mass to energy was predicted by Albert Einstein in his mass-energy equation, E = mc2 • Penetrating power of ionizing radiation is relative to radiation type and energy Module III

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