University of Notre Dame

1. University of Notre Dame Department of Risk Management and Safety 2013 Radiation Safety Refresher Training

2. INTRODUCTION • Lessons 1-5 will provide a review of some general knowledge of radiation with which all radioactive material and radiation producing machines should be familiar. • Lessons 6-14 address specific safety practices and procedures applicable to laboratories at Notre Dame

3. Lesson 1Forms of Radiation

4. Forms of Ionizing Radiation Ionizing radiation includes emissions with energies greater than 20 electron volts that cause ionizations when interacting with matter. Sources of ionizing radiation at Notre Dame include: Photon Radiation • Gamma • X-Ray Particulate Radiation • Alpha • Beta

5. Particulate Radiation • ALPHA RADIATION • Consists of two protons and two neutrons (helium nucleus) • Massive size, moving at 80% the speed of light • Internal Hazard • BETA RADIATION • Consists of an electron • Very small size moving at up to 99% the speed of light • Hazard depends on decay energy of isotope

6. Examples of Beta Emitters • H-3: Energy max = 19 Kev: Internal Hazard • C-14: Energy max = 160 Kev: Internal Hazard • S-35: Energy max = 170 Kev: Internal Hazard • P-32: Energy max = 1700 Kev: Internal and external hazard • The lower energy beta emitters are less penetrating and present less of a hazard. The concerns with these isotopes is primarily associated with internal exposure due to ingestion, inhalation, or skin absorption • Higher energy beta emitters are more penetrating and present both internal and external hazards

7. Photon Radiation • GAMMA RADIATION • A wave radiation consisting of a photon • Travels at the speed of light • Created in the nucleus of the atom • X-RAYS • A wave radiation consisting of a photon • Travels at the speed of light • Created in the electron shell of the atom

8. Examples of Gamma Emitters • I-125: Energy max = 35 Kev: Internal/External Hazard • Cs-137: Energy max= 662 Kev: Internal/External Hazard • Gamma Emitters have no mass and are very penetrating • All gamma emitting isotopes and are considered both internal and external hazards

9. e- X-ray 0 0 e- Bremsstrahlung Radiation • Literally: breaking radiation • Electromagnetic radiation produced when an electrically charged particle is slowed down by the electric field of an atomic nucleus • Example: The beta particle emitted by a P-32 atom will interact with lead to give off an x-ray • Bremsstrahlung production must be considered when planning the shielding of high energy beta emitters

10. Lesson 2Units of Radioactivity

11. The Becquerel (Bq) - International Unit 1 Bq = 1 disintegration per second 1 MBq = 1,000,000 disintegrations per second 1 GBq = 1,000,000,000 disintegrations per second Units of Radioactivity The Curie (Ci) – Commonly used in the United States 1 Ci = 3.7E10 disintegrations per second 1 Ci = 2.2E12 disintegrations per minute 1 Ci = 1000 millicurie (mCi) = 1,000,000 microcurie (uCi) 1 Bq = 2.7E-8 mCi

12. Units of Radioactivity RAD The RAD is the unit commonly used in the United States for Absorbed Dose (D) It is determined by the Energy that is actually deposited in matter 1 Rad = 100 ergs of deposited energy per gram of absorber Gray International Unit for Absorbed Dose 1 Gray = 100 Rads

13. Units of Radioactivity REM The REM is the unit commonly used in the United States for the Dose Equivalent Determined by Multiplying the absorbed dose (D) times a quality factor (Q) Q equals 1 for beta, gamma and x-rays, 5-20 for neutrons, and 20 for alpha Sievert International Unit for absorbed dose 1 Sievert = 100 REM

14. Units of Radioactivity Most labs at Notre Dame will use only beta, gamma and/or x-ray emitters The Quality factor for these forms of radiation is equal to 1 Therefore the Rad is equal to the Rem If your lab is one of the few using alpha, remember that the QF is 20. Therefore, one Rad of alpha is equal to 20 Rem. Exposure reports are documented in mREM 1 REM = 1,000 mREM

15. Lesson 3Half Life

16. Half Life • The half life of a materials is the time required for 1/2 of the radioactive atoms to decay • The half life is a distinct value for each radioisotope

17. Half Life of Selected Radioisotopes • Flourine-18: 109.8 minutes • Phosphorus-32: 14.3 days • Tritium: 12.3 years • Carbon-14: 5,730 years • Uranium: 4,500,000,000 years

18. Example of Half Life • You receive a shipment of 250 µCi of P-32 • The half life of P-32 is 14.3 days • If you do not use the P-32 until 14.3 days after receiving the material, you will only have 125 µCi left • If you wait 28.6 days, you will only have 62.5 µCi left • It is important to consider the half life of the radioisotope when planning a study that includes the use of radioactive materials

19. Lesson 4Background Radiation

20. Background Radiation • Natural and man-made sources of radiation everybody is exposed to in their daily lives • Typically 20 to 30 mRem per month

21. How Might I Be Exposed?

22. Cosmic Terrestrial Radon Medical Total 30 mRem 40 mRem 230 mRem 90 mRem 390 mRem Average Annual Exposure to the General Public

23. Lesson 5Biological Effects & Risk

24. Biological Effects • Data is largely based on high exposures to individuals within the first half of the 20th century • Biological effects occur when exposure to radiation exceeds 50 rads over a short period of time • All occupational exposures are limited by city, state, or federal regulations

25. Radiation Damage • Mechanical: Direct hit to the DNA by the radiation - Damages cells by breaking the DNA bonds • Chemical: Generates peroxides which can attack the DNA Damage can be repaired for small amounts of exposure

26. Radiosensitivity • Muscle Radioresistant • Stomach Radiosensitive • Bone Marrow Radiosensitive • Human Gonads Very Radiosensitive

27. Radiation Effects • Acute Effects: Nausea, Vomiting, Reddening of Skin, Hair Loss, Blood Changes • Latent Effects: Cataracts, Genetic effects, Cancer

28. Dose Required for Acute Effects If an individual receives a dose in excess of 50 Rem (50,000 mRem) in a short period of time, he/she will experience acute effects

29. Risk of Cancer The level of exposure is related to the risk of illness While the risk for high levels of exposure is apparent, the risk for low levels is unclear It is estimated that 1 rem TEDE of exposure increase likelihood of cancer by 1 in 1000 The likelihood of cancer in ones life time is 1 in 3 from all other factors

30. Factors Affecting Risk • The amount of time over which the dose was received • The type of radiation • The general health of the individual • The age of the individual • The area of the body exposed

31. Lesson 6Occupational Exposure

32. Whole Body Extremities Skin of Whole Body Lens of Eye Thyroid 5,000 mRem/year 50,000 mRem/year 50,000 mRem/year 15,000 mRem/year 15,000 mRem/year What are the Occupational Exposure Limits ?

33. Other Occupational Limits • ALARA - As Low As Reasonably Achievable. This is our policy AND the NRC’s: Don’t expose yourself to radiation any more than absolutely necessary.

34. Exposure to the General Public • Annual limit of 100 mRem to individuals • This includes anybody in the laboratory who does not work for Notre Dame • Examples: salesmen, vendors, family members, etc.

35. Prenatal Radiation Exposure • In the embryo stage, cells are dividing very rapidly and are undifferentiated in their structure and are more sensitive to radiation exposure • Especially sensitive during the first 2 to 3 months after conception • This sensitivity increases the risk of cancer and retardation

36. Declaring Pregnancy • Additional dose restrictions are available for the pregnant worker • Receive a monthly dosimeter • Limited to 500 mRem during the term of the pregnancy • Also, limited to 50 mRem per month • DECLARATION IS STRICTLY OPTIONAL

37. Exposure to Minors Individuals under the age of 18 • Must not receive an exposure greater than 10% of occupational exposure for adults • Wholebody Exposure Limit: 500 mRem • Minors will wear dosimeters in laboratories licensed for radioactive material use • Minors should not work with radioactive material

38. Lesson 7Minimizing Exposure

39. How Do I Protect Myself? • Reducing the dose from any source radiation exposure involves the use of three protective measures: • TIME • DISTANCE • SHIELDING

40. Time • The amount of exposure an individual accumulates is directly proportional to the time of exposure • Keep handling time to a minimum

41. Distance • The relationship between distance and exposure follows the inverse square law. The intensity of the radiation exposure decreases in proportion to the inverse of the distance squared • Dose2 = Dose1 x (d1/d2)2

42. Shielding • To shield against beta emissions, use plexiglass to decrease the production of bremsstrahlung radiation. • If necessary, supplement with lead after the plexiglass • To shield against gamma and x-rays, use lead, leaded glass or leaded plastic

43. Internal Exposure • Only a few commonly used radionuclides at Notre Dame present an external exposure potential • All radionuclides present a potential for internal exposure if taken into the body. Entry into the body can occur by inhalation, ingestion, or absorption through the skin

44. Minimizing Internal Exposure • Wear personal protective equipment • If required, use a fume hood • No eating, drinking or applying cosmetics • Clean up spills promptly • Routinely monitor work area • Secure radioactive material

45. Minimum Protective Equipment • Laboratory coat • Gloves • Safety Glasses • Dosimeters (for certain nuclides and/or machines)

46. Lesson 8Regulatory Requirements

47. Notre Dame’s License • Broadscope license issued by the Nuclear Regulatory Commission • Permits the use of radioactive material in research and development, as well as education. • Must be renewed every 10 years

48. Radiation Safety Requirements • Radiation Safety Officer • Radiation Safety Committee • Approved Responsible Investigators • Radioisotope Users

49. Records to be Kept on File By Radiation Safety -Principal Investigator -Isotope limits -Receipt of material -Waste transferred -Lab inspections -Exposure reports In the Laboratory - Receipt of material - Utilization of material (logs) - Waste disposal - Monthly Wipe tests -Training verification The NRC Inspectors will look specifically for thesecompleted documents in the lab Radiation Safety notebooks which should be stored in every radiation lab.

50. If radioactivity is not used or stored during a month, a signed statement may be substituted for a wipe test Example of Signed Statement: “There has been no radioactive material use or storage in lab ____ during the month of ____”. Records (Continued)