RADIOACTIVE AGENTS Principles of Radiation 2 types of radiation Non-ionizing (no tissue damage) Ionizing (tissue damage) 2010 MGH International Disaster Institute 1 2010 MGH International Disaster Institute 2 Effects of ionizing radiation on cells 3 2010 MGH International Disaster Institute 4 2010 MGH International Disaster Institute Types of Ionizing Radiation Electromagnetic radiation (External Irradiation) Gamma waves and x-rays - no mass or charge Passes through tissue, irradiating casualties, but leaving no radioactivity behind Electromagnetic Radiation Whole body irradiation Localized irradiation 2010 MGH International Disaster Institute 5 2010 MGH International Disaster Institute 6 1
Types of Ionizing Radiation Particle Radiation Alpha particles and Beta particles Does not easily penetrate tissue Penetrating power of ionizing radiation 2010 MGH International Disaster Institute 7 2010 MGH International Disaster Institute 8 Radiation Exposure External Contamination Internal Contamination External Contamination Radioactive debris deposited on body and clothing 2010 MGH International Disaster Institute 9 2010 MGH International Disaster Institute 10 Internal Contamination Radioactive debris inhaled, ingested, or absorbed, becoming concentrated in tissues Key Principle in Disasters Assume both types of radiation exposure when responding to disasters involving radioactive agents. 2010 MGH International Disaster Institute 11 2010 MGH International Disaster Institute 12 2
Radiation Threat Scenarios 4 Potential Threat Scenarios: Detonation of a nuclear device Meltdown of a nuclear reactor Radioactive dispersal through conventional explosives (Radioactive Dispersal Device (RDD), or Dirty Bomb ) Chernobyl (1986) 2010 MGH International Disaster Institute 13 Non-explosive dispersal of radioactive material 2010 MGH International Disaster Institute 14 Nuclear Detonation Reactor Meltdown RDD Simple Dispersal Differences between Nuclear and Conventional Explosions: LEAST LIKELY MOST HARMFUL MOST LIKELY LEAST HARMFUL Size of explosion Presence of radiation and radioactive debris 2010 MGH International Disaster Institute 15 2010 MGH International Disaster Institute 16 BLAST INJURIES Types of Injuries Overpressure waves THERMAL INJURIES Flash burns - direct absorption of infrared energy Flame Burns - burns from fires set by infrared pulse RADIATION INJURIES Irradiation by gamma waves and neutrons Radioactive debris (fallout) 2010 MGH International Disaster Institute 17 2010 MGH International Disaster Institute 18 3
Nuclear Reactor Meltdown Core must overheat causing nuclear fuel to melt. Containment failure must occur releasing radioactive material into environment. Components of a nuclear blast Reactors contain a specific mixture of radioactive elements and produce all radiation types. 2010 MGH International Disaster Institute 19 2010 MGH International Disaster Institute 20 The reactor at Chernobyl had no containment system. TREATMENT ALERT! Iodine tablets, often distributed near nuclear reactors, are effective ONLY against effects of radioactive iodine on the thyroid. Chernobyl (1986) Iodine offers no protection against radiation or other radioactive materials. 2010 MGH International Disaster Institute 21 2010 MGH International Disaster Institute 22 Radiation Dispersal Device Conventional explosive designed to spread radioactive material Simple Radiological Dispersion Simple radiological device that emits radioactivity without an explosion. No nuclear explosion Dirty bomb 2010 MGH International Disaster Institute 23 2010 MGH International Disaster Institute 24 4
Emergency Management of Radiation Casualties The shorter the time you spend near the radiation source, the less radiation exposure you receive. The farther away you are from the radiation source, the less radiation exposure you receive. Increasing shielding around a radiation source - or around you - decreases your exposure. 2010 MGH International Disaster Institute 25 2010 MGH International Disaster Institute 26 Triage of Radiation Casualties Radiation effects are delayed - triage is done according to conventional trauma protocols. Decontamination of Radiation Casualties Decontaminate before, during, or after initial stabilization, depending on severity of injury. 2010 MGH International Disaster Institute 27 2010 MGH International Disaster Institute 28 Decontamination of Radiation Casualties Externally irradiated casualties DO NOT require decontamination (Electromagnetic Irradiation). Externally contaminated casualties DO require decontamination (Particle Radiation). Removal of clothing eliminates greater than 90% of the contamination. 2010 MGH International Disaster Institute 29 Surgical Treatment of Radiation Victims Emergency surgery, as well as closure of surgical wounds, should be performed early in victims of radiation exposure. 2010 MGH International Disaster Institute 30 5
Emergency Surgery No surgery Hematopoietic Recovery Surgery Permitted Medical Effects of Ionizing Radiation 24-28 hours 3 months After 3 months 2010 MGH International Disaster Institute 31 2010 MGH International Disaster Institute 32 RISK ALERT! The severity of radiation illness is based upon the radiation dose x exposure time. Medical Effects of Radiation Focal tissue damage and necrosis Acute radiation sickness Long-term effects (weeks to decades) Cataracts, thyroid cancer, leukemia 2010 MGH International Disaster Institute 33 2010 MGH International Disaster Institute 34 Acute Radiation Syndrome ARS occurs after whole-body exposure 4 phases: Prodromal Latent Manifest illness Recovery or death 2010 MGH International Disaster Institute 35 Gastrointestinal Hematopoietic Cardiovascular Subclinical CNS 0 Gy 100 Gy Increasing Radiation Dose Effects of acute radiation syndrome vary with dose exposure. 2010 MGH International Disaster Institute 36 6
ARS: Prodromal Phase Varied symptoms: Nausea, vomiting, diarrhea, mental status changes The earlier the symptoms appear, the worse the prognosis. 2010 MGH International Disaster Institute 37 ARS: Latent Phase The shorter the latent phase, the worse the exposure. Reduced lymphocyte count may occur within 24 hours and is a good indicator of radiation dose: > 1,200 = good prognosis 300-1,200 = potentially lethal < 300 = critical 2010 MGH International Disaster Institute 38 ARS: Manifest Illness ARS: Death or Recovery Symptoms relate to the major organ systems affected by radiation (marrow, intestinal, neurovascular). Dose Dependent > 1,000 RAD (> 10 Gy): death in 72 hours without medical care 100 RAD = 1 Gy (new international unit) 2010 MGH International Disaster Institute 39 2010 MGH International Disaster Institute 40 ARS: Long-Term Effects Development of cancer Special Issues 2010 MGH International Disaster Institute 41 2010 MGH International Disaster Institute 42 7
Command Structure Incident Commander sets time limits in exposure area. All recovery personnel must be counseled about risks involved. Once a responder s maximum radiation level has been reached, that person must leave the site until the general public is allowed admission. 2010 MGH International Disaster Institute 43 Monitoring Know the limitations of your radiation detection devices! Many radiation detection devices measure only beta and gamma radiation. 2010 MGH International Disaster Institute 44 Questions 2010 MGH International Disaster Institute 45 8