Radiological Terrorism

1. Radiological Terrorism The “Dirty Bomb”

2. Dirty Bomb: Overview • A radiation dispersion device, or RDD • Conventional explosive device with radioactive material added • Radioactive material spreads to surrounding area by physical dispersion and airborne diffusion

3. Dirty Bomb Improvised explosive device Federal Bureau of Investigation image Radioactive material storage drum Department of Energy image Dirty Bomb: Overview

4. Dirty Bomb: Overview • Extent of contamination • Size and sophistication of the bomb • Type of radioactive material • Weather conditions • Extent of human exposure • Speed of evacuation from contaminated area • Example • Bomb with a single cobalt-60 rod • Acute dose of a few tenths of a rem to people within a half-mile radius

5. Dirty Bomb: The Threat • Threat of fear and disruption • Panic over radiation exposure • Produce additional casualties • Disrupt rescue and evacuation efforts • Disruption arises from area remaining off-limits and unusable during clean-up work Hazardous Materials Response Austin, TX Fire Department Image

6. Radioisotope Thermoelectric Generators (RTGs), a strontium-90 source Department of Energy Image Dirty Bomb: Materials • Most likely to be used: cobalt-60, strontium-90, cesium-137, and americium-241 • Less likely: phosphorus-32 and radium-226 • Obtained from military, medical, industrial, academic or research sources • Examples: • Cobalt-60 : food and mail irradiation • Americium-241 : smoke detectors and oil exploration • (See “Radiation Primer” for more on these isotopes)

7. Dirty Bomb: Health Risks • Radionuclides cross capillary membranes through passive and active diffusion • Rate of distribution • Organ metabolism • Ease of chemical transport • Affinity of radionuclide for chemicals in organs • Liver, kidney, adipose tissue, and bone • Greatest capacity for binding radionuclides • Higher protein and lipid makeup

8. Dirty Bomb: Health Risks • Major health risks • Acute trauma from the explosion itself • Cancer • Specific target organ damage • Heavy metal poisoning

9. Dirty Bomb: Health Risks • Cancer risk is not known • Tumor induction statistics extrapolated from data on known exposures at doses >100 rem • Extrapolated data may be inaccurate for exposures < 100 rem

10. Dirty Bomb: Health Risks • Linear, no threshold model • Endorsed by the EPA and American Federation of Scientists • Non-linear, threshold model • Endorsed by the Health Physics Society and International Council on Radiation Protection

11. Dirty Bomb: Health Risks • Linear, no threshold model • Biological damage follows a linear progression with exposure levels • The higher the dose, the greater the damage • Used to extrapolate data on exposures < 100 rem • Presents a “worst-case” scenario

12. Dirty Bomb: Health Risks • Non-linear, threshold model • Biological damage does not follow a linear progression with exposure levels • Data supports a threshold in excess of 10 rem • Delivered at high dose rates • 0.8% increase in lifetime risk for cancer • Allows for cellular repair at lower doses • 10 rem at low dose rates may not increase the risk

13. Dirty Bomb: Health Risks • Acute Radiation Syndrome unlikely • Also unlikely • Other known sequelae of radiation exposure • Cataract formation • Decreased fertility • Fetal teratogenesis • Chronic Radiation Syndrome • Requires at least 100 rem to bone marrow over a several year time span

14. Dirty Bomb: Decontamination • Primary contaminants: alpha and gamma emitters • Shoe and clothing removal will reduce contamination by 90% • Other external contaminants are particulates that can be washed off the skin and hair • Internal contaminants pose no secondary threat to healthcare workers

15. Dirty Bomb: Signs and Symptoms • The primary injuries, and their associated signs and symptoms, will be related to blast trauma • Signs and symptoms of Acute or Chronic Radiation Syndromes will not be seen (See “Nuclear Reaction” for more on these syndromes)

16. Dirty Bomb: Treatment • Inhalation exposures • Particles <5 microns move into the alveoli • Soluble particles absorbed into blood stream and lymphatic system • Mucociliary apparatus will clear larger particles • Inflammatory response with subsequent fibrosis and scarring • Clearance of these insoluble particles • Sputum induction and pulmonary “toilet”

17. Dirty Bomb: Treatment • Ingestions • Absorption depends on chemical state of the contaminant • Cesium salts are quickly absorbed • Cobalt, radium, and strontium are not absorbed • Lower GI tract becomes target organ for residual radionuclides

18. Dirty Bomb: Treatment • Ingestions • Gastric lavage and emetics help clear stomach • Purgatives, laxatives, and enemas can be administered to reduce colon exposure • Inhaled particles cleared by the mucociliary apparatus end up in the GI tract • Consider ion exchange resins to reduce GI uptake of these and other ingested radionuclides

19. Dirty Bomb: Treatment • Skin • Impermeable to most radionuclides • Wounds and burns allow radioactive particles to by-pass the epithelium • Meticulously clean and debride all wounds and burns

20. Dirty Bomb: Treatment • Heavy metal poisoning • Consider chelation therapy where appropriate • Calcium edetate (EDTA) • Used primarily to treat lead poisoning • Also consider dimercaprol and penicillamine • DTPA more effective in removing many of the heavy-metal, multivalent radionuclides

21. Dirty Bomb: Treatment • Isotope specific treatments • Americium-241 • Use DTPA or EDTA chelation in the first 24 to 48 hours following pulmonary exposure • Cesium-137 • Early use of lavage and purgatives • Prussian blue and ion exchange resins are useful

22. Dirty Bomb: Treatment • Isotope specific treatments • Cobalt-60 • Gastric lavage and purgatives for ingestions • Penicillamine chelation in severe cases • Phosphorus-32 • Lavage, aluminum hydroxide, and oral phosphates.

23. Dirty Bomb: Treatment • Isotope specific treatments • Radium-226: • Immediately lavage after ingestion • Fecal elimination may be increased by ammonium chloride

24. Dirty Bomb: Treatment • Isotope specific treatments • Strontium-90 • Oral administration of aluminum phosphate immediately after ingestion • Administration of stable strontium • Calcium and acidification of the urine with ammonium chloride will increase excretion

25. Dirty Bomb: Summary • Known as a radiation dispersal device (RDD) • Conventional explosive device with radiological material added • Main threat is one of fear and disruption • Most likely radioisotopes to be used: cobalt-60, strontium-90, cesium-137, and americium-241

26. Dirty Bomb: Summary • Major health risks include • Acute blast trauma • Cancer • Specific target organ damage • Heavy metal poisoning • A non-linear, threshold model of exposure is favored by health physicists

27. Dirty Bomb: Summary • Primary injuries will be related to blast trauma • Signs and symptoms of Acute or Chronic Radiation Syndromes will not be seen • Treatment : rapid elimination of the radionuclide from the body • Pulmonary “toilet” for inhalation exposures • Gastric lavage and purgatives for ingestions • Debridement and cleansing for skin wounds

28. Dirty Bomb: Summary • Chelation therapy for cases of potential heavy metal poisoning • Specific treatment regimens advised for each isotope with potential for use in a RDD