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The Nuclear Incident. Management of Nuclear Casualties. Hospital Management of Nuclear Casualties. Terminal Objective. Be able to describe the various types of radiological hazards. Become familiar with the acute health effects from radiation contamination and exposure.
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The Nuclear Incident Management of Nuclear Casualties
Terminal Objective • Be able to describe the various types of radiological hazards. • Become familiar with the acute health effects from radiation contamination and exposure. • Become familiar with the principles of diagnosis, treatment and management of radiation casualties.
Radiological and Nuclear Devices CONCEPTUAL DISPERSAL DEVICE SHIELDED CONTAINER RADIOACTIVE MATERIAL HIGH EXPLOSIVE • Simple radiological device • Radiological dispersal device • Reactor • Improvised nuclear device • Nuclear weapon
The Basics of Radiation • Ionizing radiation is electromagnetic energy or energetic particles emitted from a source. • Ionizing radiation is able to strip electrons from atoms causing chemical changes in molecules.
The Basics of Radiation Biological Molecular Damage Biological Damage Chemical Damage Free Radicals 10-10 Seconds 1. Proteins 2. Membrane 3. DNA Cells, tissues, whole animals Hours to years Seconds to hours
Ionizing Radiation - Alpha • 2 neutrons and 2 protons • Highly ionizing • Travels several centimeters in air and a few microns in tissue • Component of nuclear fallout • Stopped by a thin paper or clothing • Threat is inhalation or absorption of alpha emitter in wounds
Ionizing Radiation - Beta • High energy “electron” emitted from nucleus • Can have wide range of energies depending upon the particular radionuclide • Moderately penetrating • Up to a few meters in air • Millimeters in tissue
Gamma or X-Ray (Photons) • High energy rays • Very penetrating • Difficult to shield • Can be produced from radioactive decay and a nuclear weapon explosion or reactor accident
Ionizing Radiation - Neutrons • Neutral particle emitted from the nucleus • Can be very penetrating • Requires special consideration for shielding
Examples of Radioactive Materials SubstanceHalf LifeEmitUse Americium 241 458 years a, g Smoke Detectors Cobalt 60 5.3 years b, g Medical Therapy Plutonium 238 86.4 years a Thermoelectric Gen. Plutonium 239 24,400 yrs a Reactors and Weapons Radium 226 1,602 yrs a Medical Therapy Uranium 238 millions yrs a,b, g Reactors and Weapons Iridium 192 74 days b, g Industrial Radiography
Radiation Half-Life • Time required for a radioactive substance to lose half of its radioactivity • Each radionuclide has a unique half-life • Half-lives range from extremely short (fraction of a second) to millions of years Examples: Tc-99m 6.0 hrs I-131 8.05 days Co-60 5.26 yrs Sr-90 28.1 yrs Pu-239 24,400 yrs U-238 4,150,000,000 yrs
Radiation - Units of Measure • rad - basic unit for measuring radiation • rem - quantifies the amount of damage that is suspected from a particular type of radiation dose
Radiation Doses in Perspective Natural background and manmade radiation 360 mrem / yr Diagnostic chest x-ray 10 mrem Flight from LA to Paris 4.8 mrem Barium enema 800 mrem Smoking 1.5 ppd 16,000 mrem / yr Heart catheterization 45,000 mrem Mild acute radiation sickness 200,000 mrem LD50 for irradiation 450,000 mrem mrem = millirem = 1/1000 of a rem
Types of Radiation Exposure • External irradiation - whole-body or partial-body • Contamination by radioactive materials - external (deposited on the skin) or internal (inhaled, swallowed, absorbed through skin, or introduced through wounds) • Incorporation of radioactive materials - uptake by body cells, tissues, or organs (bone, liver, kidney, etc) • Combined radiation injury - combination of the above complicated by trauma.
Radiation Injury - External Irradiation · · s · Partial Body · Local · · Whole Body
Radiation Injury - Contamination External Internal
Radiation Injury - Incorporation Thyroid Lung Liver Bone
Radiation - LD50 • We know what radiations are produced • We know how to measure them • But the body senses cannot detect radiation. Therefore, how can we measure the biological damage? • LD50/30 Animals • LD50/60 Human
Examples of LD50 for Given Species SpeciesDose (rads) • Guinea Pigs 250 LD 50/30 • Goat 350 LD 50/30 • Man 250-450 (LD 50/60) • Mouse 570 LD 50/30 • Rat 550-800 LD 50/30 • Frog 700 LD 50/30 • Snail 8,000-20,000 LD 50/30
Severity of Injury The higher the dose, the more severe the early effects and the greater the possibility of delayed effects
Acute Radiation Syndrome (ARS) • Group of symptoms that develop after total body irradiation (> 100 rads) • May occur from either internal or external radiation • Four important factors are: • High Dose • High Dose Rate • Whole Body Exposure • Penetrating Radiation
ARS - Phases • Prodromal Phase - occurs in the first 48 to 72 fours post-exposure and is characterized by nausea, vomiting, and anorexia. At doses below about 500 rads last 2 to 4 days. • Latent Phase - follows the prodromal phase and lasts for approximately 2 to 2 1/2 weeks. During this time, critical cell populations (leukocytes, platelets) are decreasing as a result of bone marrow insult. The time interval decreases as the dose increases. • Illness Phase - period when overt illness develops • Recovery or Death Phase - may take weeks or months
ARS - Hematopoitic SystemBlood Count RBC Cell Reduction Neutrophils Lymphocytes Platelets 24-hr 1 week 2 weeks 3 weeks
ARS - Hematopoietic Syndrome 3.0 2.5 Normal Range 2.0 Absolute Lymphocytes (109/L) 1.5 Moderate 1.0 Severe Patient Injury 0.5 Very Severe 0.1 Lethal 0 3 6 17 24 48 hrs
ARS - Gastrointestinal Syndrome • Radiation > 600 rads • Damages intestinal lining • Nausea and vomiting within the first 2 - 4 hours • May develop diarrhea • Associated with sepsis and opportunistic infections • At 10 days could develop bloody diarrhea resulting in death
ARS - Central Nervous System • Seen with radiation dose > 1,000 rads • Microvascular leaks Õ edema • Elevated intracranial pressure • Death within hours
ARS - Skin Dry Desquamation Moist Desquamation Erythema Necrosis Epilation Response 300 600 1000 >1500 >5000 Dose
ARS & Trauma • Radiation and Trauma = á Mortality • Trauma is the first priority
Treatment • Wound and burn care, surgery, and orthopedic repair should be done in the first 48 hours or delayed for 2 to 3 months Emergency Surgery Hemopoietic Recovery No Surgery Surgery Permitted 24 - 48 Hours After 3 Months 3 Months
Survival Time Survival Time Hematopoietic Gastrointestinal CNS/ CVS 200 Rads 1000 Rads 100,000 Rads
Classification, Treatment & Disposition • Patients are classified in three categories based on signs and symptoms: • Survival probable < 100 rads • Survival possible 200 - 800 rads • Survival improbable > 800 rads
Classification, Treatment & Disposition Incorporation / Internal Contamination • Various medications can be used to limit uptake or facilitate removal of radioactive material • Numerous medications are approved by the FDA. Certain drugs are investigational and can be used in an emergency (i.e. Radiogardase [Prussian Blue] and DTPA) • NCRP 65
Radiation Protection Principles • Time • Distance • Shielding
Key Points • No antidote for radiation exposure - treatment is primarily supportive • Minimal risk to responding personnel from radiation contaminated patients • Early symptoms are an indication of the severity of the radiation dose • Consult with specialists for “survivable groups” • Treat life-threatening injuries first