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Radiological Terrorism

Radiological Terrorism. Nuclear Reaction. Nuclear Reaction: Overview. Two main scenarios exist Nuclear blast (warhead, suitcase nuke). XX-01 The Stokes Test, conducted at the Nevada Test Site on August 7, 1957 U.S. Department of Energy image. Nuclear Reaction: Overview.

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Radiological Terrorism

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  1. Radiological Terrorism Nuclear Reaction

  2. Nuclear Reaction: Overview • Two main scenarios exist • Nuclear blast (warhead, suitcase nuke) XX-01 The Stokes Test, conducted at the Nevada Test Site on August 7, 1957 U.S. Department of Energy image

  3. Nuclear Reaction: Overview • Two main scenarios exist • Power plant reactor meltdown Three Mile Island Nuclear Power Plant near Harrisburg, Pennsylvania U.S. Department of Energy image

  4. Nuclear Reaction: Overview • Nuclear blast produces • 60-second pulse of extremely high dose gamma and neutron radiation • Radioactive fission products within the fallout area close to ground zero XX-12 GRABLE was fired on May 25, 1953 at the Nevada Test Site. U.S. Department of Energy image

  5. Nuclear Reaction: Overview • Reactor meltdown produces • High-level nuclear reaction releasing large amounts of gamma and neutron radiation • Without an explosion Nuclear Power Plant Cooling Towers U.S. Department of Energy image

  6. Nuclear Reaction: Overview • Meltdown is the result of • Complete loss of the cooling system • High heat melts containment rods in the reactor core Nuclear Power Plant Cooling Towers U.S. Department of Energy image

  7. Nuclear Reaction: Overview • Both forms of nuclear reaction result in: • Sudden high dose gamma and neutron radiation release • Major challenge for medical response • High-level nuclear reactions are the only source of neutron radiation • Produced only during nuclear reaction • Not a fallout hazard

  8. Nuclear Reaction: Radioisotopes • Plutonium-239/238 is the primary fissionable material used in power plants and weapons • Uranium-238/235/234 may also be encountered (See “Radiation Primer” for more on these isotopes)

  9. Nuclear Reaction: Radioisotopes • A nuclear reaction may produce: • Americium-241, a decay daughter of plutonium • Strontium-90, a fission product of uranium • Radioactive iodine (iodine-131/132/134/135), a fission by-product (See “Radiation Primer” for more on these isotopes)

  10. Nuclear Reaction: Health Risks • The intense, high dose-rate exposure caused by a nuclear reaction produces both direct and indirect biological damage • Direct: by ionization of cells • Indirect: by ionization of body water, producing unstable, toxic hyperoxide molecules that can damage subcellular structures

  11. Nuclear Reaction: Health Risks • Actively dividing cells are most vulnerable • Hematopoietic and gastrointestinal systems

  12. Nuclear Reaction: Health Risks • Without appropriate medical care – • The LD50/60 is estimated to be 3.5 Gy (equals 350 rem for gamma radiation) • With modern medical care – • Nearly all radiation casualties are considered treatable if care is quickly made available

  13. Nuclear Reaction: Health Risks • Acute Radiation Syndrome is likely and of greatest concern • Tumor induction is the most important long-term health sequelae from high dose radiation • Latency period for radiation-related cancers may be several years

  14. Nuclear Reaction: Health Risks • Other sequelae of radiation exposure include: • Cataracts • 200 rem threshold for acute gamma exposure • 1500 rem for chronic exposure • May develop 6 months to many years later

  15. Nuclear Reaction: Health Risks • Other sequelae of radiation exposure include: • Infertility • Whole body exposure of 12 rem causes transient azoospermia – 600 rem, permanent sterility

  16. Nuclear Reaction: Health Risks • Ionizing radiation has four main effects on fetus: • Growth retardation • Severe congenital malformations • Embryonic, fetal, or neonatal death • Carcinogenesis

  17. Nuclear Reaction: Health Risks • Peak incidence of teratogenesis occurs during period of fetal organogenesis • CNS is most commonly involved • Other organ malformations are less likely in humans

  18. Nuclear Reaction: Decontamination • Primary contaminants will be alpha and beta emitters • Simply removing clothing and shoes will reduce contamination by approximately 90%

  19. Nuclear Reaction: Decontamination • Other external contaminants are particulates that can be washed off the skin and hair • Internal contaminants pose no secondary threat to healthcare workers

  20. Acute Radiation Syndrome • Acute Radiation Syndrome (ARS) is the result of a sudden, high dose-rate exposure to radiation • Presents as a sequence of phased symptoms • Symptoms vary with individual’s radiation sensitivity, type of radiation, and the dose

  21. Acute Radiation Syndrome • Prodromal phase: • Early onset of nausea, vomiting, and malaise, as well as fatigue, fever, headache, and diarrhea • Larger doses produce symptoms earlier • Radiogenic vomiting can be confused with psychogenic vomiting from stress and fear

  22. Acute Radiation Syndrome • Latent phase: • Relatively symptom-free period following the prodromal phase • Longer in lower dose exposures causing only bone marrow suppression

  23. Acute Radiation Syndrome • Latent phase: • Shorter (days to a week) with higher doses leading to marrow suppression and gastrointestinal syndrome • Brief (hours) in extremely high doses that produce CNS syndrome

  24. Acute Radiation Syndrome • Manifest illness phase: • Clinical symptoms of the injured organ systems are displayed • Primary syndromes • Bone marrow suppression • Gastrointestinal Syndrome • CNS (Neurovascular) Syndrome

  25. Acute Radiation Syndrome • Bone marrow suppression • Not just marrow, but also spleen and lymphatic system – all blood-forming organs • Injury occurs with exposures >100 rem (1 – 4 Gy) • Peripheral blood smear changes within 24 hours

  26. Acute Radiation Syndrome • Bone marrow suppression • Lymphocytes decrease most rapidly but ultimately pancytopenia develops • Immune system compromise and anemia develop between 10 – 45 days post-radiation

  27. Acute Radiation Syndrome • Gastrointestinal Syndrome • Occurs with exposures > 600 – 1000 rem (6 – 10 Gy) • Stomach and intestinal tract injured • After a short latent period, nausea, vomiting, diarrhea, dehydration, electrolyte imbalances, and bleeding ulcers with hemorrhage develop

  28. Acute Radiation Syndrome • Gastrointestinal Syndrome • Damage to the luminal epithelium and submucosal vasculature causes the loss of intestinal mucosa • Since marrow suppression also occurs, radiation enteropathy produces no inflammatory response

  29. Acute Radiation Syndrome • CNS (Neurovascular) Syndrome • At doses >2000 – 4000 rem (20-40 Gy), the CNS and other nervous tissue are damaged • Victim displays a steadily worsening state of consciousness leading to coma and death • Convulsions may or may not occur

  30. Acute Radiation Syndrome • CNS (Neurovascular) Syndrome • Signs of  ICP may or may not be evident • Individuals receiving such high doses are well in range of 100% lethality due to blast and thermal effects

  31. Acute Radiation Syndrome • Other organ injuries: • 50 rem: thyroid damage • 125-200 rem: ovarian damage • 200-300 rem: skin erythema and hair follicle damage • 600 rem: gonadal damage with permanent sterility

  32. Chronic Radiation Syndrome • Syndrome defined by exposure of at least 100 rem to the marrow for at least 3 years

  33. Chronic Radiation Syndrome • Victim complaints include: • Sleep/appetite disturbances • Generalized weakness/rapid fatigue • Poor concentration or impaired memory • Headaches / chills • Bone pain and hot flashes

  34. Chronic Radiation Syndrome • Clinical findings • Localized bone or muscle tenderness • Mild hypotension, tachycardia, intention tremor • Ataxia, asthenia, and hyperreflexia

  35. Chronic Radiation Syndrome • Reproductive effects in exposed children include: • Delayed menarche • Underdeveloped secondary sexual characteristics

  36. Chronic Radiation Syndrome • Lab findings include mild to marked pancytopenia and bone dysplasia • Gastric hypoacidity and dystrophic changes may be present • Clinical findings slowly resolve when patient is removed from continued exposure • Complete recovery possible with lower doses

  37. Treatment: ARS • During prodromal phase, provide supportive care and oral antiemetics • Granisetron or ondansetron • Antiemetics are not radioprotectants

  38. Treatment: ARS • With bone marrow suppression, the prevention and management of infection governs therapy • Antibiotic prophylaxis in afebrile patients with profound neutropenia (< 0.1 x 109 cells/l) • With prolonged neutropenia, risk of secondary infections increases

  39. Treatment: ARS • With bone marrow suppression, the prevention and management of infection governs therapy • Consider using cytokine hematopoietic growth factors, such as filgrastim or sargramostim, to stimulate hematopoiesis -- must be started within 72 hours of exposure

  40. Treatment: ARS • It must be assumed during the care of all patients that even those with a typical gastrointestinal syndrome may be salvageable • Replacement of fluids and prevention of infection by bacterial transmigration is mandatory

  41. Treatment: General • Inhalation exposures: • Particles <5 microns move into the alveoli • Soluble particles are absorbed into the blood stream and lymphatic system • Residual particles produce inflammatory response with subsequent fibrosis and scarring

  42. Treatment: General • Inhalation exposures: • Mucociliary apparatus will clear larger particles • Consider sputum induction and pulmonary “toilet” to aid the clearance of these insoluble particles

  43. Treatment: General • Ingestions: • Absorption depends on chemical state of the contaminant • Radioiodine is quickly absorbed • Plutonium and strontium are poorly absorbed, if at all • Lower GI tract becomes target organ for residual radionuclides

  44. Treatment: General • Ingestions: • If used promptly, gastric lavage and emetics can help clear the stomach • Purgatives, laxatives, and enemas can be administered to reduce colon exposure

  45. Treatment: General • Inhaled particles cleared by the mucociliary apparatus end up in the GI tract • Consider ion exchange resins to reduce GI uptake

  46. Treatment: General • Skin: • Impermeable to most radionuclides • Wounds and burns may hide weak alpha and beta emissions from detection • All wounds and burns must be meticulously cleaned and debrided

  47. Treatment: General • Heavy metal poisoning: • Consider chelation therapy where appropriate • Calcium edetate (EDTA): • Used primarily to treat lead poisoning • Use with extra caution with preexisting renal disease

  48. Treatment: General • Heavy metal poisoning: • Diethylenetriaminepentaacetic acid (DTPA) is more effective in removing many of the heavy-metal, multivalent radionuclides • Also consider dimercaprol and penicillamine

  49. Treatment: Specific • Isotope specific treatments: • Americium-241: Use DTPA or EDTA chelation in first 24 to 48 hours following pulmonary exposure. • Plutonium-239/238: Administer 1 g CaDTPA within 24 hours of exposure; followed by 1 g ZnDTPA qd while monitoring urine levels. • Radioiodine: Potassium Iodide (see later slides)

  50. Treatment: Specific • Isotope specific treatments: • Strontium-90: • Aluminum phosphate decreases absorption by up to 85% • Stable strontium inhibits metabolism and increases excretion • Calcium and acidification of urine with ammonium chloride increases excretion

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