Radiation “Awareness”

1. Radiation “Awareness” • Objectives • To increase public understanding of radiation and radioactivity • To provide basic radiation-science information for use by science teachers • Health Physics Society • Specialists in Radiation Protection

2. Outline • Radiation theory & basics • Exposure and effects • Ways to minimize exposure • Beneficial uses in modern society • Resources and additional information

3. Why Are Elements Radioactive? • Unstable nucleus: • Has excess energy. • Wants to go to “ground state.” • Becomes stable by emitting ionizing radiation. What does “ionizing” mean?

4. Who Discovered Radioactivity? Antoine Henri Becquerel • Worked with uranium. • Noticed phosphorescence caused film exposure after leaving uranium in the sun. • Noticed same thing happened on cloudy days.

5. Radiation Types Alpha Particles (2n, 2p) Beta Particles (e-or+) Photons (hv) (x or gamma rays) Paper Concrete

6. 3H Beta particle 3He Ion N N P N e P P e Anti Neutrino Ionizing RadiationsBeta Decay

7. The Electromagnetic Spectrum Figure courtesy of NASA/JPL-Caltech

8. 137Ba 137mBa Gamma ray Excited Nucleus Ionizing Radiations Gamma Emission

9. Definitions • Radioactive decay is a spontaneous process in which nucleons are emitted from or transformed within the nucleus, resulting in a change in the identity of the nucleus, and usually accompanied by the emission of one or more types of radiation from the nucleus and/or atom. • Half-life is the time required for half of the atoms of a radioactive material to decay to another nuclear form.

10. Who’s the Famous “Madame” of Radiological Fame? Marie Curie • With her husband Pierre, discovered radium and coined the term “radioactive” • First woman to win two Nobel Prizes

11. Units of Radioactivity • The becquerel (Bq) or • The curie (Ci) 1 Ci = 37,000,000,000 Bq so 1 mCi = 37 MBq and 1 µCi = 37 kBq

12. Approximate Radioactivityin Assorted Items Item or Process mCi MBq • Smoke Detector 0.001 0.037 • Biomedical Lab Experiment 0.5 18.5 • Nuclear Medicine Dose 10 370 • Industrial Radiography Source 40,000 1,480,000

13. Natural Background Radiation

14. Man-Made Radiation

15. Cell Death Biological EffectsMechanisms of Injury Ionizing Radiation Cell Damage Transformation Repair

16. After Image (film) Subject is not radioactive but has been exposed to a radiation dose (single chest x ray = 5-10 mrem). Radiation Dose Dose or radiation dose is a generic term for a measure of radiation exposure. In radiation protection, dose is expressed in millirem. External Dose X-Ray Machine

17. Contamination Contamination is the presence of a radioactive material in any place where it is not desired, and especially in any place where its presence could be harmful. Yuck!

18. Radiation Detection Instruments Photo by Karen Sheehan Photo by Carl Tarantino Geiger Counter Liquid Scintillation Counter

19. Lessons from the Past The Radium Dial Painters Photo by Carmelina Rattrovo from the Playwrights Theatre production of Radium Girls, by D.W. Gregory

20. Annual Radiation Dose LimitsGeneral Public vs. Occupational Established by the Nuclear Regulatory Commission • General Public Limit - 100 mrem • Occupational Limit - 5,000 mrem Remember – We get approximately 300 mrem per year from natural background exposure.

21. Minimizing Radiation Exposure Basic Concepts • Time • Distance • Shielding

22. Minimizing Exposure - Time • Minimize the amount of time spent near sources of radiation.

23. Minimize Exposure by Maximizing Distance As the distance from a radioactive source doubles, the exposure rate decreases by a factor of four.

24. Minimizing Exposure By Using Shielding Lead blanket shielding around letdown radiation monitors Surry Power Station

25. Loss of Life Expectancy Activity or Behavior LLE (DAYS)__________________ Recreational swimming 40 Being 15 percent overweight 900 Smoking 20 cigarettes per day 1,600 Using pesticides at home 12 Being exposed to radon in a home 35 Living within 10 miles of a nuclear power plant 0.4 Riding a bicycle 6 Driving a car 200 Skydiving 25 Consuming alcohol (U.S. average) 230

26. Medicine and Research • Colleges • Doctors’ Offices • Hospitals • Pharmaceutical • Research and Development

27. Research: As a “Tracer” • Radioactivity is an excellent tool! • Detectable in minute quantities (like finding one grain of sand on a small beach containing 6,000,000,000 granules)

28. Power Generation Nuclear power supplies 20 percent of energy in the United States. There are 104 nuclear power plants in the United States. Photo by Karen Sheehan

29. Space Exploration The fuel in: • Satellites • Jupiter Probe • Others Jupiter Probe

30. Who Discovered X Rays? Wilhelm Conrad Roentgen Roentgen worked with a Crookes tube to study cathode rays.

31. How X Rays Work

32. X Rays (continued)

33. Other Types of X-Ray Machines Photos by Karen Sheehan

34. X-Ray Crystallography Photo by Karen Sheehan

35. Nuclear Medicine Diagnostic Procedures • Radioactive injection • Short half-life radionuclide • Pictures taken with special gamma camera • Many different studies: Thyroid Lung Cardiac White Blood Cell Photo by Karen Sheehan

36. Bone Scans Image courtesy of

37. Radiation Therapy Used for treating cancer. Why does it work? Photo by Karen Sheehan Image courtesy of Brachytherapy (implants) External Beam

38. Radioactive Consumer Products Photo by Karen Sheehan

39. For more information about radiation you may contact the Health Physics Society. http://www.HPS.org Health Physics Society Specialists in Radiation Safety

40. Additional References • Hall E. Radiation and life, 2nd ed. New York: Pergamon Press; 1984. • Bushong SC. Radiologic science for technologists, 7th ed. St Louis, MO: Mosby, Inc.; 2001.