Radiation Safety Training

1. ICN Dosimetry Service Radiation Safety Training Understanding and Working Safely with Radiation Tosh Ushino, CHP Radiation Safety Officer Revision 0, April 2000

2. What is radiation and what does it mean to me? [Or, are bananas radioactive and is that why King Kong got to be that big?] • Did it exist before the bomb? • Will I get cancer from it? • How can I ensure my safety?

3. There is so much misinformation about radiation We learned about radiation and its effects watching Sci Fi movies and TV shows • Incredible Hulk, mutation caused by radiation • Spiderman, bitten by a radioactive spider • Godzilla, mutated from a weapon test • Teenage Mutant Ninja Turtles, from radioactive waste • and many others…… Unfortunately, lots of people think this is all true…. • and of course, Mr. Spock of Star Trek, after all his exciting adventures across the universe, died of radiation exposure

4. Where does Radiation come from? Atoms are composed of particles • Nucleus: • protons with positive (+) charge • neutrons with no charge • Outer shell: • electrons with negative (-) charge

5. Where does Radiation come from? (cont’d) Neutrons act like to glue to hold nucleus together • Protons don’t want to stay together • There are about equal numbers of protons and neutrons in nucleus • If the numbers are out of balance, then the nucleus is unstable

6. Where does Radiation come from? (cont’d) • Number of protons in nucleus determines what kind of element the atom is • Number of neutrons in the nucleus determines the isotope of that element

7. Where does Radiation come from? (cont’d) Example: • Stable Hydrogen • Nucleus composed of one proton(normal hydrogen) • Nucleus composed of one proton and one neutron(deuterium) • Unstable Hydrogen (radioactive) • Nucleus composed of one proton and two neutrons(tritium)

8. Where does Radiation come from? (cont’d) Example: (cont’d) In a process called “radioactive decay,” unstable nucleus eventually becomes stable by ejecting • excess particles • excess energy Radiation is the ejected excess energy or particle “Activity” is the measure how much isotopes are undergoing decay

9. What is Ionizing Radiation? There are 2 types of radiation: • sub-atomic particles • electromagnetic waves Typically, particles are parts of atoms • alpha (helium nucleus) • beta (electron) • positron (positive anti-electron) • neutron (component of nucleus) You can find exotic particles in cosmic ray and at high energy accelerators

10. What is Ionizing Radiation? (cont’d) Electromagnetic waves are: • Like light or radio-waves you cannot see • Emitted in packets of energy called “photons” • X-Ray • Gamma Ray

11. What is Ionizing Radiation? (cont’d) • Gamma Rays • from nucleus of atom • from annihilation of electron and positron • X-Rays • from orbital electrons • from high energy electrons (and positrons) slowing down (call “Bremsstrahlung”) • Ionizing radiation has enough energy to strip electrons off of atom or molecule

12. Primordial isotopes Uranium series Thorium series Radium series Potassium-40 (K-40) Continually produced by natural process H-3, C-14 Generated through man’s activity Tc-99m, Cs-137, Pu-239 Where do isotopes come from?

13. Where do we get most of our radiation exposure? • We live in an ocean of radiation • Radiation comes from earth, space, and food we eat • Life on earth evolved and flourished in higher level of natural radiation than today

14. Natural Sources of Radiation Cosmic Ray High energy radiation from the sun and deep space Terrestrial Radiation Radiation emitted from natural radioactivity in soil, minerals and rocks Nuclide Deposition Radiation from natural radioactivity in our bodies, from food and air

15. ELECTROMAGNETIC RADIATION SOLAR WIND ENERGETIC PARTICLES POLAR CUSP Space Weather The sun emits both electromagnetic radiation and electrically charged particle streams which can interact with the near-earth environment. These radiations vary in intensity over time

16. Man-made Sources of Radiation • Nuclear Medicine • Radioactive tracers for diagnostic therapy • Analytical procedures • Pacemakers • Medical X-Rays (produced by x-ray tubes) • Fluoroscopy • Chest X-Ray • Dental X-ray

17. Man-made Sources of Radiation (cont’d) • Consumer products • Television sets • Smoke detectors • Fossil fuel: coal, gas • Air travel • Luminous compounds • Building materials • Nuclear fuel cycle • Above-ground bomb tests

18. Can you become radioactive if you get exposed to radiation? You are already radioactive • Radioactivity is a nuclear process • Radiation we encounter day-to-day only affects electrons around the nucleus • If you come into a dark room from sunlight, can others see you glow in the dark? • If you heat your food in microwave oven, does the food emit microwave as you are eating it? • Radioactivity can be induced only if exposed to neutron or beam from an accelerator

19. How much radiation exposure is allowed per year? Radiation Worker: • Whole body: 5,000 mrem • Lens of the eye: 15,000 mrem • Skin: 50,000 mrem • Extremity: 50,000 mrem • Pregnant radiation worker 500 mrem for the entire gestation period • Fetus is radiation sensitive due to rapidly dividing cells General Public: • Whole body: 100 mrem* [*up to 500 mrem w/prior authorization]

20. How much radiation dose do we receive from Mother Nature? 300 mrem/year (national average) • It increases with: • elevation • latitude • It varies with: • geology of the area where you live • type of food you eat • type of homes you live in • your lifestyle (smoking, air travel, etc.) If you live in Denver, you’ll receive more radiation from cosmic ray and granite

22. Radiation Effects • Radiation Effect depends on • How much radiation dose you receive • How quickly you receive the dose • What part of the body receives it, and • whether you receive any medical treatment • Radiation sensitivity depends on how rapidly cells divide

23. Acute Radiation SyndromeWhole Body Exposure Hemopoietic syndrome (>200,000 mrads) • Depression or ablation of bone marrow • Malaise and fatigue, epilation • Potential death due to infection if no medical treatment given Gastrointestinal syndrome (>1,000,000 mrads) • Desquamation of intestinal epithelium • Severe nausea, vomiting, diarrhea Central nervous system syndrome (>2,000,000 mrads) • Damage to central nervous system & other body organs • Unconsciousness within few minutes

24. How does ionizing radiation cause cell and tissue damage? Direct damage to DNA • DNA damage is expressed only when damaged cells divide • Most of the damaged DNA are repaired. If not, the cell may die; or a tiny fraction may persist

25. How does ionizing radiation cause cell and tissue damage? (cont’d) Indirect damage through formation of hydroxide “free” radicals (hydrogen peroxide) • Free radicals may damage DNA • At extremely high dose, cells are killed by damage to cell membrane from high levels of radicals

26. How much DNA damage will I get? • Recent study shows 10,000 mrem of radiation (2x the annual limit for workers) causes ~200 single strand and ~4 double strand breaks per cell • This study also shows chemical and thermal effects (from day-to-day living) cause ~150,000 single strand and ~200 double strand breaks per cell per year

27. How much DNA damage will I get? (cont’d) Typical American receives ~300 mrem of natural radiation per year • So, ~0.004% of DNA damage may be from natural radiation, and If radiation worker receives 5,000 mrem, • <0.07% of DNA damage may be from occupational radiation exposure

28. How effective is radiation in causing DNA damage? • In the study of cancer, researchers induce malignant transformation in cells • Chemical carcinogens like benzopyrene is much more effective than radiation in producing cancer cells • It may take 10,000’s, if not 100,000’s of mrads to produce the same effect as the amount of benzopyrene in a single cigarette* [* Dr. Ann Kennedy, University of Pennsylvania]

29. So, how come we are not all dropping dead of cancer? • On the average, about 1/3 of all people get cancer from all causes • Currently, about 17% of people die from cancer Population of U.S. is about 300 million Eventually all those people would die ~ 100 million would get cancer ~ 50 million of those would die from cancer

30. So, how come we are not all dropping dead of cancer? (cont’d) Natural repair mechanism in our bodies eliminate most of the damaged cells • Damaged cells that are not eliminated by the repair mechanism may become cancerous • Cancer incidence rate rises with age • So, if you live long enough, you will get cancer

31. What is the likelihood that you’ll die from cancer due to occupational exposure? Highly unlikely!

32. Cancer Deaths Attributed to Various Sources Source Cancer Deaths (%) Diet 35 Range: 10 - 70 Tobacco 30 Range: 25 - 40 Infection 10 Sexual lifestyle 7 Range: 1 - 13 Occupation 4 Alcohol 3 Natural Environment 3 Pollution 2 Medical Care 1 Food Additives 1 Industrial Products 1 Unknown -

33. So why is there so much scare about radiation? • We can’t see it, smell it, or feel it • It is not part of our daily experience • Because of that, we do not have a proper perspective of the relative risks • We read scary headlines • Written by people who probably don’t know any more than you do • On the other hand, several dozen people die each day due to traffic accidents, but people continue to ride cars, trains and airplanes because we are used to it

34. Radiation is a tool • Radiation has many wonderful uses • Diagnose disease • Cure cancer • Analytical tools for industry and medicine • Sterilize medical equipment and food, etc • Like anything, it can be misused, and • Like anything, too much is not good for you

35. What Safety Precautions should I take? • Use Common Sense • Not so common after all • Time, Distance and Shielding • Minimize Time • Maximize Distance • Maximize Shielding (heavier the better) • Follow safety procedures

36. History of Radiation Accidents • Nearly all, if not all, radiation accidents were caused by workers • not paying attention to what they were doing • deliberately violating procedures • deliberately circumventing safety devices • Devices do fail occasionally, but good procedures and training would account for that possibility • You can make the devices and procedures as “Idiot-Proof” as possible • but those “idiots” can be very clever