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ANALYTICAL X-RAY SAFETY User Training

Centre for Environmental Health, Safety and Security Management. ANALYTICAL X-RAY SAFETY User Training. Analytical X-ray Safety Training – User Training TRAINING OUTLINE. History Sources/uses of X-rays Legislation Biological & Health Effects X-ray safety in the lab References Quiz.

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ANALYTICAL X-RAY SAFETY User Training

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  1. Centre for Environmental Health, Safety and Security Management ANALYTICAL X-RAY SAFETYUser Training

  2. Analytical X-ray Safety Training – User Training TRAINING OUTLINE • History • Sources/uses of X-rays • Legislation • Biological & Health Effects • X-ray safety in the lab • References • Quiz RYERSON UNIVERSITY

  3. Analytical X-ray Safety Training - User Training BIOLOGICAL& HEALTH EFFECTS Radiation is one of the best-investigated hazardous agents RYERSON UNIVERSITY

  4. RYERSON UNIVERSITY

  5. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSFactors Determining Biological Effects • Total dose • Dose rate • Energy of radiation • Amount of body exposed • Cell and individual sensitivity RYERSON UNIVERSITY

  6. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSFactors Determining Biological Effects TOTAL DOSE • Effects from acute doses (> 1 Sv = 100 rem) easily observed • < effects on chronic dose at 0.1Sv effects not reliably quantifiable due to no observable effects RYERSON UNIVERSITY

  7. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSDose (D) • effects from radiation depend on amount of radiation received (absorbed) by the body • Called Dose or Absorbed Dose (D) • quantity of energy deposited in a unit of mass of material • Units of Measure: Gray (Gy) or rad 1 Gy = 100 rad RYERSON UNIVERSITY

  8. Most conservative model: An increase in dose results in a proportional increase in risk 1 At low doses there is only a slight increase in risk that becomes proportional to dose at higher doses 2 There is a threshold for dose response at which lower doses do not result in increased risk 3 Hormesis model (not shown): Low doses of radiation have a positive effect and decrease overall risk 4 Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSRadiation Dose Response Curve RYERSON UNIVERSITY

  9. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSEquivalent Dose (H) • biological effect caused by radiation being deposited in human body • dependant on type of radiation and energy • quality factor (QF) used to relate the absorbed dose of various kinds of radiation to the biological damage caused to the exposed tissue since different kinds of radiation cause different degrees of damage. • the higher the quality factor, the greater biological risk or greater effect than the radiation with a lower quality factor (for the same absorbed dose) RYERSON UNIVERSITY

  10. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSFactors Determining Biological Effects LOW RADIATION DOSE (Chronic) Chronic exposure when a relatively small amount of radiation is absorbed by tissue over a long period of time - result in an increased risk in latent adverse health effects < 100 mSv of exposure - No detectable health effects in exposed individual Historical Doses @ Ryerson Averaged < Reporting Threshold of TLD (<0.1 mSv) RYERSON UNIVERSITY

  11. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSFactors Determining Biological Effects LARGE RADIATION DOSE (Acute) Biological Effects from large doses potentially occur due to accidental exposures Acute exposure when a large amount of radiation is absorbed by tissue over a single period of time • 2 – 10 Sv cause radiation sickness • > 10 Sv cause death RYERSON UNIVERSITY

  12. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSFactors Determining Biological Effects DOSE RATE • Dependent on amount of radiation over period of time (exposure) • Acute vs chronic • If amount of radiation same, acute dose more damaging, since tissues does not have time for repairs RYERSON UNIVERSITY

  13. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSFactors Determining Biological Effects ENERGY OF RADIATION • X- rays have wide range of energies (10 to100 KeV) • Higher the energy deeper the penetration into tissue • Lower energy x-ray absorbed first layers of skin (shallow dose) RYERSON UNIVERSITY

  14. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSFactors Determining Biological Effects AMOUNT OF BODY EXPOSED • Harder and more damaging for body to recover from dose to large area of body than a small, localized area such as hand • Might include sensitive organs RYERSON UNIVERSITY

  15. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSFactors Determining Biological Effects SENSITIVITY • Individual sensitivity to absorbed radiation • Type of cells: some more radiosensitive such as those undergoing cell division RYERSON UNIVERSITY

  16. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTS 2 different types of health effects: • Genetic Effects • Somatic Effects RYERSON UNIVERSITY

  17. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSGenetic Effects Biological effect inherited by children resulting from a modification of genetic material in a parent • No genetic effects observed in humans only in animal studies • No statistically significant genetic effects observed in children in Japanese atomic bomb survivors (any effects on offspring from nuclear bombing survivors in Japan in WW2 from women already pregnant) RYERSON UNIVERSITY

  18. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSSomatic Effects Biological effect observed in our lifetime to exposed individual (not carried to offspring) • At doses 5 Sv (=5000 mSv), skin begins to show “sunburn • Eye damage (cataracts) can results at doses > 6 Sv (=6000 mSv) Typical Ryerson doses <0.1 mSv RYERSON UNIVERSITY

  19. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSRisk of Cancer • Radiation exposure including exposure to x-rays does not cause any unique forms of cancer that are not normally observed in humans • Risk estimates derived mostly from survivors of WWII atomic bombings Evaluation of risk • The risk of cancer from radiation exposure is conservatively assumed to be linear with dose • If 1 million people were exposed to 10 mSv then hypothetical estimates of 100 additional leukemia and 700 additional other cancers greater from an acute dose of 10 mSv (BEIR V report) Typical Ryerson doses < 0.1mSv RYERSON UNIVERSITY

  20. Analytical X-ray Safety Training - User Training BIOLOGICAL & HEALTH EFFECTSHealth Effects of X-rays • Due to localized nature of X-ray beams, acute doses to whole body NOT USUAL • Most health effects occur due to chronic exposure • Most exposure to analytical X-rays results in exposure to skin and extremities RYERSON UNIVERSITY

  21. Continue on to:X-ray Safety in the Lab Return to Main Menu RYERSON UNIVERSITY

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