Preparing for an Unplanned Radiation Event

1. Preparing for an Unplanned Radiation Event Niel Wald, M.D. Michael P. Kuniak, D.O., M.P.H.

2. Acknowledgments Prepared by the Radiological Emergency Medical Preparedness & Management Subcommittee of the National Health Physics Society Ad Hoc Committee on Homeland Security. Jerrold T. Bushberg, PhD, ChairKenneth L. Miller, MS Marcia Hartman, MS Robert Derlet, MDVictoria Ritter, RN, MBA Edwin M. Leidholdt, Jr., PhD ConsultantsFred A. Mettler, Jr., MD Niel Wald, MD William E. Dickerson, MD Appreciation to Linda Kroger, MS who assisted in this effort.

3. Christine Hartmann Siantar, Ph.D. Deputy Program Leader Nuclear and Radiological Countermeasures Monterey Institute of International Studies Center for Nonproliferation Studies Resource Links CIF 2004-2005 (http://cif.miis.edu/resource.htm) Associate Professor UC Davis

4. OUTLINE Radiation Terrorism and Response • Radiation Basics • Radiation Protection Rules • Radiation Threats Nuclear device, “dirty” bomb Equivalent Experiences: Chernobyl, Goiana 4. Health Management of Affected Population

5. What is Radiation? • For the purpose of this presentation, defined as energetic emissions from unstable atoms that can result in ionizing events to target atoms • Ionizing radiation is radiation capable of imparting its energy to the body and causing chemical changes • Ionizing radiation is emitted by • - Radioactive material • Some devices such as x-ray machines

6. Common Radiation Terms • Radioisotope - a generic name for a radioactive element • Radionuclide - a specific radioisotope such as Uranium-235 • These terms are often used interchangeably

7. Radiation Physics • Ionizing Radiation • Radiation with enough energy to cause ionization of atoms by ejecting electrons from their atomic orbits • Types of Radiation • Electromagnetic (Photons - No Mass) • X-ray, Gamma • Particulate • Alpha (helium nucleus), Beta (electron), Proton, Neutron

8. Types of Radiation Emitted from Radioactive Material • Particulate • Charged • Alpha Radiation • Beta Radiation • Uncharged • Neutron Radiation • Electromagnetic • Gamma Radiation

9. Types of Ionizing Radiation Alpha Particles Stopped by a sheet of paper Radiation Source Beta Particles Stopped by a layer of clothing or less than an inch of a substance (e.g. plastic) Gamma Rays Stopped by inches to feet of concrete or less than an inch of lead

10. Alpha and Beta Radiation • Alpha • Typically emitted from a heavy element • Most have energies between 4-8 MeV • Particles up to 7.5 MeV stopped by dead skin layer (only a few microns penetration) • Can be shielded by paper • Penetrates a few cm in air • Does not penetrate the dead layer of skin • Beta • Travels about 4 meters in air per MeV • Penetrates about 0.5 cm in soft tissue per MeV • Can reach the basal cell layer of skin

11. Pertinent Alpha Emitters

12. Neutron Radiation • Neutral particle emitted from the nucleus • Can be very penetrating • Requires special consideration for shielding • Can induce radioactivity when absorbed by stable elements (N, Na, Al, S, Cl, P, etc.)

13. Electromagnetic Radiation • Energy = hf • Energy expressed typically in KeV or MeV (not joules) • Absorption of Electromagnetic Radiation by matter • Photoelectric • Compton Scattering • Pair production (photon energy must exceed 1.02 MeV) • Stochastic event • Low energy photons more readily absorbed

14. The Electromagnetic Spectrum

15. Gamma Radiation • Electromagnetic energy emitted from the nucleus • Specific energies can be analyzed to identify source • Very penetrating (many meters in air) • Difficult to shield, often shielded with lead

16. X-ray Radiation • Electromagnetic energy emitted from outside the nucleus • May be “machine-produced” by bombarding high energy electrons on a target • May also be emitted from radioactive materials • Similar shielding and penetrating powers as gamma radiation

17. Radiation Units Measure of Amount of radioactive material Ionization in air Absorbed energy per mass Absorbed dose weighted by type of radiation Quantity Activity Exposure Absorbed Dose Dose Equivalent Unit curie (Ci) roentgen (R) rad rem For most types of radiation 1 R  1 rad  1 rem

18. Units of Radioactivity • Quantity • 1 Becquerel (Bq) = 1tps • 1 Curie (Ci) = 3.7 x 1010 tps • Exposure • 1 Roentgen (R) = 2.58 x 10-4 C/Kgair  87.7 ergs/gair • Exposure to Dose Relationship • 1 R exposure  95 ergs/g absorption in muscle

19. Half-Life • The time required for a radioactive substance to loose 1/2 of its radioactivity • Each radionuclide has a unique half-life • Half-lives range from extremely short (fraction of a second) to billions of years

20. Example of the Effect of Half-Life • Assume an initial amount of 32 uCi of TC-99m with a half-life (T1/2) of 6 hours • after 1 half-life (6 h): 16 uCi • after 2 half-lives (12 h): 8 uCi • after 3 half-lives (18 h): 4 uCi • after 4 half-lives (24 h): 2 uCi • After 10 half-lives, less than 1/1000 of the original activity remains

21. Selected Radionuclides with Radiations From Mettler, Jr., F.A. and Upton, A.C., Medical Effects of Ionizing Radiation 2nd edition

22. Absorbed Dose (D) 1 Gray (Gy) = 1 J/Kg 1 rad = 100 ergs/g 100 rad = 1 Gy Dose Equivalent (HT) [ HT = DQ] 1 Seivert (Sv) = 1 J/Kg 1 rem = 100 ergs/g 100 rem = 1 Sv Radiation Dose Deterministic Acute Effects Stochastic Late Effects Note: 1 MeV = 1.6 x 10-13 Joules

23. Weighting Factors

24. Radiation Doses and Dose Limits Flight from Los Angeles to London 5 mrem Annual public dose limit 100 mrem Annual natural background 300 mrem Fetal dose limit 500 mrem Barium enema 870 mrem Annual radiation worker dose limit 5,000 mrem Heart catheterization (skin dose) 45,000 mrem Life saving actions guidance (NCRP-116) 50,000 mrem Mild acute radiation syndrome 200,000 mrem LD50/60 for humans (bone marrow dose) 350,000 mrem Radiation therapy (localized & fractionated) 6,000,000 mrem

25. Radioactive Material • Radioactive material consists of atoms with unstable nuclei • The atoms spontaneously change (decay) to more stable forms and emit radiation • A person who is contaminated has radioactive material on their skin or inside their body (e.g., inhalation, ingestion or wound contamination)

26. Examples of Radioactive Materials Physical RadionuclideHalf-LifeActivityUse Cesium-137 30 yrs 1.5x106 Ci Food Irradiator Cobalt-60 5 yrs 15,000 Ci Cancer Therapy Plutonium-23924,000 yrs 600 Ci Nuclear Weapon Iridium-192 74 days 100 Ci Industrial Radiography Hydrogen-3 12 yrs 12 Ci Exit Signs Strontium-90 29 yrs 0.1 Ci Eye Therapy Device Iodine-131 8 days 0.015 Ci Nuclear Medicine Therapy Technetium-99m 6 hrs 0.025 Ci Diagnostic Imaging Americium-241 432 yrs 0.000005 Ci Smoke Detectors Radon-222 4 days 1 pCi/l Environmental Level

27. Radioactive Material Any substance that spontaneously gives off radiation Can be in various chemical forms If not contained (sealed source) can lead to contamination - External, Internal or Both Radiation The energetic emissions of radioactive material Can be subatomic particles (, , n), photons (X-ray, ) or combinations Results in ionization of the absorbing material (if living tissue  radiation injury) Radiation vs. Radioactive Material

28. Half-Life (HL) • Physical Half-Life Time (in minutes, hours, days or years) required for the activity of a radioactive material to decrease by one half due to radioactive decay • Biological Half-Life Time required for the body to eliminate half of the radioactive material (depends on the chemical form) • Effective Half-Life The net effect of the combination of the physical & biological half-lives in removing the radioactive material from the body • Half-lives range from fractions of seconds to millions of years • 1 HL = 50% 2 HL = 25% 3 HL = 12.5%

29. Criticality Incident Operation Upshot/Knothole, a 1953 test of nuclear artillery projectile at Nevada Test Site

30. Nuclear Fission

31. Fissile Material • U-235 • Enriched from 0.7% (Natural) to 3%  > 90% • Used: • Commercial Reactors • Research Reactors • Naval Reactors • Atomic Bomb • Pu-239 • Byproduct of U-235 fission • Used in Breeder Reactor • Also can be weaponized

32. Radionuclides of Concern

33. Causes of Radiation Exposure/Contamination • Accidents • Nuclear reactor • Medical radiation therapy • Industrial irradiator • Lost/stolen medical or industrial radioactive sources • Transportation • Terrorist Event • Low yield nuclear weapon • Radiological dispersal device (dirty bomb) • Attack on or sabotage of a nuclear facility

34. Size of Event Event No. of Deaths Most Deaths Due to Radiation None/Few Radiation Accident Few/Moderate Radioactive Blast Trauma (Depends on Dispersal size of explosion & Device proximity of persons) Blast Trauma Low Yield Large Thermal Burns (e.g. tens of thousands in NuclearWeapon an urban area even from Radiation Exposure 0.1 kT weapon) Fallout (Depends on Distance)

35. Dose Limits - ICRP 60

36. Emergency Exposure Guidelines - ICRP 60

37. Radiography Source

38. 13 Curie Cs-137 Radiography Source Found by a man at an Argentina construction site Carried in front pockets for 18 hours Sealed Source Accident

39. Accident Dose Calculation • Cs-137 Gamma Constant = 0.323 R-m2/hr-Ci • 0.323 R-m2x (18hr)(13Ci)= 755,820 R hr-Ci (0.01m)2

40. Accident Isodose Curves

41. Basic Radiobiology • Atom Ionization in Water or Cell Molecules Molecule Chemical Damage Bond Breakage DNA Chromosomal Aberration Cell Death Mutation

42. Lymphocytes Erythroblasts Myeloblasts Epithelial Cells Intestinal crypts Testis Ovary Skin Secretory glands Lungs and bile ducts Endothelial Cells Connective Tissue Cells Tubular Cells of Kidneys Bone Cells Nerve Cells Brain Cells Muscle Cells Radiosensitivity(most to least): 19-A

43. Classification of Medical Radiation Problems • Anxiety • Acute Radiation Syndrome • Local Radiation Injury • External Radionuclide Contamination • Local Trauma with Radionuclide Contamination • Internal Radionuclide Contamination

44. Radiation Injuries • External exposure to penetrating radiation • Criticality Incident (,N) • Sealed Source (,) • External Contamination (, ) • Beam Generator (,N) • Internal contamination with radionuclides • Wound Contamination (, , ) • Injection (, , ) • Inhalation (, , ) • Ingestion (, , )

45. Late Health Effects from Radiation • Radiation is a weak carcinogen at low doses • No unique effects (type, latency, pathology) • Natural incidence of cancer ~ 40%; mortality ~ 25% • Risk of fatal cancer is estimated as ~ 4% per 100 rem • A dose of 5 rem increases the risk of fatal cancer by ~ 0.2% • A dose of 25 rem increases the risk of fatal cancer by ~ 1%

46. What are the Risks to Future Children?Hereditary Effects • Magnitude of hereditary risk per rem is 10% that of fatal cancer risk • Risk to caregivers who would likely receive low doses is very small - 5 rem increases the risk of severe hereditary effects by ~ 0.02% • Risk of severe hereditary effects to a patient population receiving high doses is estimated as ~ 0.4% per 100 rem

47. Fetal IrradiationNo significant risk of adverse developmental effects below 10 rem Weeks After Fertilization Period of Development Effects <2 2-7 7-40 All Pre-implantation Organogenesis Fetal • Little chance of malformation. • Most probable effect, if any, is death of embryo. • Reduced lethal effects. • Teratogenic effects. • Growth retardation. • Impaired mental ability. • Growth retardation with higher doses. • Increased childhood cancer risk. (~ 0.6% per 10 rem)

48. Types of Radiation Hazards Internal Contamination • External Exposure - • whole-body or partial-body (no radiation hazard to EMS staff) • Contaminated- • external radioactive material: on the skin • internal radioactive material: inhaled, swallowed, absorbed through skin or wounds External Contamination External Exposure

49. Radioactive Contamination • Contamination is simply the presence of radioactive material where it is not wanted • Persons may be contaminated either externally, internally or both • Exposure does not necessarily imply contamination

50. Shielding: If you have a thick shield between yourself and the radioactive materials more of the radiation will be absorbed, and you will be exposed to less. Distance:The farther away from the blast and the fallout the lower your exposure. Time:Minimizing time spent exposed will also reduce your risk. In order to limit the amount of radiation you are exposed to, think about:SHIELDING, DISTANCE and TIME