Содержание
- 2. Radiation quantities and units The basic radiation quantities are: exposure dose absorbed dose equivalent dose effective
- 3. Exposure = ionization air The old unit to measure exposure is roentgen (R), which is defined
- 4. Absorbed dose = energy/mass When ionizing radiation interacts with the human body, it gives its energy
- 5. One gray dose is equivalent to one joule radiation energy absorbed per kilogram of organ or
- 6. Equivalent dose The third important radiation quantity is the dose equivalent. Equal doses of all types
- 7. To account for this difference, radiation dose is expressed as equivalent dose in units of sievert
- 9. Equivalent dose is often referred to simply as “dose” in energy day of radiation terminology. The
- 10. 1Sv = 100 rem 1 rem = 10 mSv (millisievert = one thousandth of a sievert)
- 11. What effects do different doses of radiation have on people? One sievert is a large dose.
- 12. Here are some examples: 10 Sv – Risk of death within days or weeks 1 Sv
- 13. What are the limits of exposure to radiation? The Threshold Limit Values (TLVs) published by the
- 14. What is the relationship between SI units and non-SI units? Table 2 shows SI units (International
- 16. What is “committed dose?” When a radioactive material is gets in the body by inhalation or
- 17. What is an effective dose? The effective dose is the sum of weighting equivalent doses in
- 18. Tissue weighting factors (Table 3) represent relative sensitivity of organs for developing cancer.
- 21. ** The remainder is composed of the following additional tissues and organs: adrenal brain upper large
- 22. Integral dose Integral dose is the radiation quantity that is equal to the total energy absorbed
- 23. Measuring radiation by ionization methods Common types of wearable dosimeters for ionizing include: film badge dosimeter
- 24. Quartz fiber dosimeter A quartz fiber dosimeter, sometimes simply called a pocket dosimeter, is a pen
- 25. If the radiation is more or less constant, it is possible to measure the ionizing current.
- 26. A simple dosimeter of this type is a pocket or pen dosimeter. A capacitor is charged
- 28. Gold leaf electroscopeGold leaf electroscope showing principle of fiber dosimeter. When ionizing radiationGold leaf electroscope showing
- 29. Quartz fiber dosimeter
- 30. Quartz fiber dosimeter
- 32. Dosimeter charger Essential for recharging quartz fibre dosimeters.
- 33. Film badge dosimeter Film badge dosimeter, is a dosimeter used for monitoring exposure to ionizing radiation.
- 34. The film is removed and developed to measure exposure. The film is sensitive to radiation and,
- 35. Advantages: The film badge has several advantages over other types of dosimetry: permanent record of exposure
- 37. Film badge dosimeter
- 38. Thermoluminescent Dosimeter Thermoluminescent dosimeters (TLD) are often used instead of the film badge. Like a film
- 39. Advantages: The advantages of a TLD over other personnel monitors are its: linearity of response to
- 40. How it works A TLD is a phosphor, such as lithium fluoride (LiF) or calcium fluoride
- 41. Heating the crystal causes the crystal lattice to vibrate, releasing the trapped electrons in the process.
- 42. Instead of reading the optical density (blackness) of a film, as is done with film badges,
- 43. Thermoluminescent Dosimeter
- 44. Thermoluminescent Dosimeter
- 45. Dosimeter-radiometer The dosimeter-radiometer, which has many unique qualities: a thin graphical display, which shows the information
- 46. the dosimeter-radiometer generates sound signals to indicate the following events: — one or several particles detection;
- 47. Dosimeter-radiometer
- 48. The effects of radiation on the cell at the molecular level When radiation interacts with target
- 49. For direct actions, damage occurs as a result of ionization of atoms on key molecules in
- 50. However, when exist, as in high radiation fluence, orbital neutrality can be achieved by: hydrogen radical
- 51. Ionizing radiation DNA damage active enzymatic repair processes exist for the repair of both DNA base
- 52. residual unrejoined double strand breaks are lethal to the cell, whereas incorrectly recoined breaks may produce
- 55. Stochastic effects Stochastic effects are those that occur by chance and consist primarily of cancer and
- 56. In summary, stochastic effects are: totally random (occur by chance) appear in non-exposed persons as well
- 57. Non stochastic effects (acute) Unlike stochastic effects, non stochastic effects are characterized by a threshold dose
- 58. Examples of non stochastic effects include: erythema (skin reddening) skin and tissue burns cataract formation radiation
- 59. Summary of non stochastic effects: Threshold – a certain minimum dose must be exceeded before the
- 62. Teratogenic effects Teratogenic effects are effects from some agent that are seen in the offspring of
- 63. Somatic effects Somatic effects are effects from some agent, like radiation that are seen in the
- 64. Genetic effects Genetic effects are effects from some agent that are seen in the offspring of
- 65. This chest burn was produced when a powerful radiation source was placed in a shirt pocket.
- 66. This damage was caused by handling a powerful radiation source, without protection.
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