Difference between revisions of "Radiation exposure (disaster)"

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== Background ==
 
== Background ==
  
*potentially easy to deal with since lots of people deal with radiation daily- univ, hosp, military
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*“Ionizing” radiation is electromagnetic or particulate in nature and has sufficient energy to cause ejection of an electron from an orbital shell of a target atom, thus creating charged particles or ions. Non-ionizing radiations, ( e.g., light, microwaves, and radiowaves), do not have sufficient energy to eject an electron from another atom. Ionization of biologically important molecules, e.g., DNA, can cause cellular death by several mechanisms. Ionizing radiation at higher doses can cause damage to actively dividing and undifferentiated cell types, e.g., stem and progenitor cells in the bone marrow, gastrointestinal system, and skin.
*easy to detect with geiger counters
 
*immediate effects well known and easy to assess with blood counts
 
  
 
=== Radiological and Nuclear Scenarios of Concerns<br> ===
 
=== Radiological and Nuclear Scenarios of Concerns<br> ===
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[[Category:Rads]] [[Category:Tox]] [[Category:EMS]]
 
[[Category:Rads]] [[Category:Tox]] [[Category:EMS]]
<ref>Planning Guidance for the Resposne to a Nuclear Detonation (2nd Edition)</ref>
 

Revision as of 18:00, 20 September 2013

Background

  • “Ionizing” radiation is electromagnetic or particulate in nature and has sufficient energy to cause ejection of an electron from an orbital shell of a target atom, thus creating charged particles or ions. Non-ionizing radiations, ( e.g., light, microwaves, and radiowaves), do not have sufficient energy to eject an electron from another atom. Ionization of biologically important molecules, e.g., DNA, can cause cellular death by several mechanisms. Ionizing radiation at higher doses can cause damage to actively dividing and undifferentiated cell types, e.g., stem and progenitor cells in the bone marrow, gastrointestinal system, and skin.

Radiological and Nuclear Scenarios of Concerns

  • Nuclear Power Plant Incidents/Accidents
  • Radiological Exposure Devices
  • Radiological Dispersal Devices
  • Improvised Nuclear Devices

Radiological Exposure Devices

  • minimally radioactive sources maybe used to create fear and panic- ex- exempt low level radioisotopes from nuc medicine, research. no immediate effects and probability of long term effects low
  • highly radioactive substances- cobalt, cesium, iridium- used in radiotherapy and radiographic machines have penetrating radiation so easy to detect at check points
  • if souce is metallic- there will be radiation exposure but no contamination. if powder get both exposure and contamination
  • if handle it, will get local skin injury and are risk for acute radiation syndrome

Radiological Dispersal Devices

  • is greater concern since will be able to spread to more people and assoc traumatic injuries- will also cause additional fear, panic
  • extent of dispersal depends on physical form of source- solid or powder, explosive type, atmospheric conditions
  • health hazard only a few city blocks- goal of response to monitor and contain.

Nuclear Power Plant Incident/Accident

  • reactor if steel vessel in concrete building. if damaged, is designed to slow down stop reaction
  • if cooling system damaged, may get some radiation leak- radioactive iodine and noble gases
  • gas escape for reactor core will have immediate nearby health effects and rad iodine can have thyroid CA in kids long term at great diistances
  • many nuclear engineering dept at univ have small reactors and are easy targets
  • spent radioactive fuel rods stored in less secure places but hard to expose large population to this solid source

Nuclear Device Detonation

  • unlikely use by terrorists since needs high level of expertise- but low yield weapon can be made or higher yield weapon could be stolen and used
  • even if nuc weapon fizzled- will still be big blast
  • destruction due to airblast and thermal radiation
  • 1 psi increase breaks glass
  • 12 psi 50% mortality
  • fire ball -> flash/ flame burns, blindness
  • inonizing radiation released in first minute as intense pulse- is initial radiation
  • residual radiation, after first minute is fission and activation products
  • ground burst causes radioactive soil into atmsphre and fallout of hundreds of miles- fallout can be lethal at greater ranges than at the blast or fireball

Basic Principles

Physical Properties

  • gamma and xrays- deep penetration
  • alpha- hazard only if ingested/ inoculated since penetration <0.1mm
  • beta/ electrons- penetrate a few centimeters
  • Rads- is dose absorbed by specific tissue. internation unit for absorbed dose is "gray" Gy. 1 gy = 100 rads
  • different radioactive particles have diff effects at same absorbed dose- so use effective dose for comparison
  • effective dose is "REM". 100 rem = 1 sievert
  • one gray = one sievert when dealing with gamma and beta rays
  • effect of radiation based on time of exp, distance and shielding
  • dose decreases rapidly with square of distance and decreases on 1/9th if triple distance
  • shield with lead or stay indoors
  • radiation decays with time
  • short lived- iodines
  • long- cesium, stontium, cobalt
  • rate of decay also effects dose of exposure and may effect management decisions

Biological Principles

  • some cells may die but if cells role not critical for survival, may not see effect
  • rapidly dividing cells- gi and bone marrow, most vulnerable
  • dose <1gy, cells survive but get CA later
  • radiation induced CA dose related
  • leukemia within 2 yrs, solid tumors 5-10 or more yrs

Treatment

  • can be localized or whole body, internal or external deposition and contamination
  • mostly not emergency, just tx sxs and supportive care

Localized Exposure

  • by direct handling. pt survives eventhough dose high since exposure drops rapidly with distance
  • rad burn like thermal burn- but signs can occur after a few days, vasc insuff after several months and causing necrosis of previously healed skin
  • tx c pain control, infc prophylaxsis, vasodilator tx, surg, skin graft,
  • extent of penetration important factor in outcome
  • beta rays from fallout only burn exposed skin

Whole Body Exposure

  • Acute Radiation Syndrome
    • Within 12hr, N/V for 48hr
    • Dose >30 gy: CV and CNS effects - hypotension, cerebral edema, sz, n/v/d, ataxia, death
    • Dose 10-30 gy: GI syndrome: N/V/D, then latent for 1 wk, then recurrent n/v/d this time with sepsis and death
  • hematopoetic syn- dose 2gy or higher- lymphocyte reduction within 48 hrs is indicator for rad exposure. get leukopenia and thrombocytopenia- bleeding and infc- may enhance recovery by hematopoetic factors
  • cutaneous syn- damaged skin may interact with other organ damage
  • amifostine- prophylactic radiation drug- causes hypotn as side effect unfortunately
  • androstenediol- boosts immune system
  • bone marrow xplant not helpful
  • even if tx and survive hematopoetic syn, still die from radiation pneumonitis, denuded gi tract, hepatic and renal dysfunction

Internal Contamination

  • may enter thru burns, wounds, inhale, ingest
  • need to know type of radionuclide and chemical form
  • need to tx quickly to be effective
  • reduce absorption, dilute, blockage, displacement by non radioactive materials, mobilization, chelation
  • potassium iodine for nuc weapon detonation or reactor breach- prevents radioiodine from accumulating in thyroid. take shortly after exp to be effective- if give too much get iodism
  • dose- 130 mg adults, 65 mg 3- 18ys, 32 mg 1mo- 3yr, 16 mg for age< 1mo
  • chelators- calcium, zinc, only for plutonium or americium

External Contamination

  • clothes and exp skin- just clean up and prevent spread
  • clean with soap and water
  • if extremis- stabilize first, then decontam
  • do not abraid skin while cleaning

Contaminated Burns and Wounds

  1. irrigate
  2. excise only if long acting radionuclides
  3. if whole body dose >1gy, close wound asap to prevent portal of infc
  4. in burns, radioactivity comes off with eschar and exudate

Disaster Management

  • preparation, crisis management, consequences
  • FBI is lead agency in terrorist incident
  • during consequence management, FEMA fed emerg management agency takes over
  • intervention- action to reduce exp and dose of radtn
  • if dose 1 rem- stay in doors up to 2 days- evacuate for 1 wk if dose of 5 rem or more
  • temp relocation if dose 3 rem in first month or 1 rem in subsequent month
  • permanent resettlement if lifetime dose 100 rem
  • pot iodine only if thyroid dose 100 mgy or more
  • EMS occupational dose of 5 rem per yr dose not apply- allowable dose goes up for life saving event
  • at dose of 0.1 gy/hr- ems may go in for short time but dose maybe life threatening

Early Management Concerns

  • Early management concerns are scenario dependent

Longer Term Concerns