Radiation exposure (disaster): Difference between revisions
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*at dose of 0.1 gy/hr- ems may go in for short time but dose maybe life threatening | *at dose of 0.1 gy/hr- ems may go in for short time but dose maybe life threatening | ||
=== Early Management === | === Early Management Concerns === | ||
* | *Early management concerns are scenario dependent | ||
=== Longer Term Concerns === | |||
[[Category:Rads]] [[Category:Tox]] [[Category:EMS]] | [[Category:Rads]] [[Category:Tox]] [[Category:EMS]] |
Revision as of 17:50, 20 September 2013
Background
- potentially easy to deal with since lots of people deal with radiation daily- univ, hosp, military
- easy to detect with geiger counters
- immediate effects well known and easy to assess with blood counts
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
- irrigate
- excise only if long acting radionuclides
- if whole body dose >1gy, close wound asap to prevent portal of infc
- 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