Response to Radioactive Events
  • No tags were found...

Response to Radioactive Events

Principles of Radiation:Outline of what we will coverJargonTypes of radiation– Ionizing vs non-ionizing– Alpha, beta, gamma (and other Greek letters)Types of exposure– Through– On– InHow a radiation event can happenMedical effects of radiationWhat disaster teams needs to know3

JargonConfusing, huh? Let’s s put it in terms we have a feelfor– One belly CT (older CT, not newer super-high resolution) isaround 1000 mrem = 1 remWe will talk about BCAT’s (belly CT equivalents, NOT a real unit, Imade it up); BCAT = rem– CXR = 10 mrem = 0.01 BCAT– XRT prior to BMT = +/-1000 BCAT’S, usually split over acouple of days6

Types of RadiationOverviewNon-ionizing radiation (does not affect tissues)Ionizing radiation– Changes atom or a group of atoms net electrical charge by gaining g orlosing one or more electronsTranslation: It hits stuff and makes it change, so risk for damage to cells.We will concentrate on this.80% of ‘normal’ ionizing radiation is from natural sources.– About 364 mrem/yr (add 280 mrem/yr for smokers) from cosmic (29), terrestrial (29),radon (200), internal (40), manmade (39), nuclear med (14), consumer products (11),travel (2)– So < ½ BCAT, and this is per year!7

Types of Radiation ExposureOverviewThrough (external)– Alpha, beta, gamma and neutrons do not contaminate patientOn (external)– Radioactive elements (such as from a dirty bomb) do contaminate patientsRemoval of clothes does 90% of the deconIn (internal)– Ingested– Inhaled– By puncture (famous umbrella spy assassination)– Absorbed through the skin– Body fluids can be radioactive8

Focus on Ionizing RadiationElectromagnetic radiation (photons )– Gamma waves and x-raysxrays—no mass or charge.Translation: this is light (visible and all spectrums)!Total energy is intensity (number photons) times energy perphoton (E = hf)– Passes through tissue, irradiating casualties, but leavingno radioactivity behind, so no residual radioactivity onthe person.– No residual radiation hazard to medical providers– Key is how much radiation is absorbed (the stuff thatpasses through is not a worry)Different wavelengths have different penetration/absorption (Qfactor)9

Different Wavelengths of Light10

Focus on Ionizing RadiationParticulate RadiationAlpha particles (nucleus of Helium)Beta particles (electrons)Neutrons11

Focus on Ionizing RadiationRadioactive elements give off particles as they decay; the particles gothrough, but the radioactive elements can be on or in– If dirty bomb can be left on patient– Can be ingested, inhaled, injected or absorbed (in(patient)– ExamplesCesiumThalliumPlutoniumCuriumAmericiumUraniumPlutoniumRadiumKryptonite (only for superman)Many others12

Focus on Types of RadiationExposureThrough– Gamma (light)Lots of concrete stops it– Particle Radiation (Think: charged stuff easilystopped, bumps into charges in materials)Alpha particles (nucleus of Helium)– Paper stops itBeta particles (electrons):– Clothes stops itNeutrons:– Penetrates a meter of concrete13

Penetrating power of ionizing radiation14

Focus on Types of RadiationExposureON (CONTAMINATION)– Radioactive particulate debris depositedon body and clothingDirty bomb for example– Minimal hazard to medical providersClothing removal is 90% of deconCan treat with no worries after clothingremoval15

Focus on Types of RadiationExposureIN (INTERNAL) CONTAMINATION– Radioactive debris inhaled, ingested, injected orabsorbed, becoming concentrated in particulartissuesRussian agent poisoned in England– Potential hazard to medical providers (wounds,vomitus, , surgical procedures)– Treatments existID agent if possibleTertiary care– Specialized treatments (Prussian Blue, chelation)– Supportive (as with chemo/XRT patients)16

How Can a Radioactive EventOccur?17

PracticalityRadioactive agents are:– Expensive– Require some technical know how– May be a bit harder to obtain– However, a sophisticated terrorist groupmay be capable of designing orpurchasing a workable nuclear bomb or“dirty bomb”18

4 Potential Threat ScenariosDetonation of a nuclear deviceMeltdown of nuclear reactorRadioactive dispersal through conventionalexplosives (Radioactive Dispersal Device-RDD or “Dirty Bomb”)Non-explosive dispersal of radioactivematerial19

4 Potential Threat ScenariosNuclearDetonationReactorMeltdownRDDSimpleDispersalLEAST LIKELYMOST HARMFULMOST LIKELYLEAST HARMFUL20

Scenario 1:Detonation of a Nuclear DeviceBLAST INJURIES– Overpressure wavesTHERMAL INJURIES– Flash burns: direct absorption of infraredenergy– Flame Burns: burns from fires set by infraredpulseRADIATION INJURIES– Irradiation by gamma waves and neutrons21

Where the Energy Goes40-50%5% (ionizing)+10% (fallout)30-50%Part of the ‘radiation’ energyComponents of a Nuclear Blast22

Scenario 2:Nuclear Reactor MeltdownCore must overheat causing nuclear fuel to meltContainment failure must occur releasing radioactivematerial into environment– The reactor at Chernobyl had no containment systemRadioactive materials released– Reactors contain a specific mixture of radioactive elements and produceall radiation types23

Scenario 3:Dirty BombConventional explosive designed to spreadradioactive material– No chain reaction occurs, but radioactive material is spewedNo nuclear explosion“Dirty bomb”24

Homeland Security DisasterPlanning Scenario (2005)Terrorists set off bombs with radioactivecesium 137 in three nearby moderate-toto-largecities, contaminating 36 city blocksCasualties at each site: 180 dead, 270 injuredand 20,000 contaminatedEconomic impact: up to billions of dollars25

Scenario 4:Simple Radiological DispersionEmits radioactivitywithout an explosion.– Example: Placement of aCobalt 60 radioisotope in apublic place.26

Medical Effects ofIonizing Radiation27

Medical Effects of RadiationOverviewFocal tissue damage and necrosisAcute radiation sicknessLong-term effects (weeks to decades)– Cataracts, thyroid cancer, leukemia, othercancers28

Acute Radiation SyndromeARS occurs after whole-bodyexposure4 phases:– Prodromal– Latent– Manifest illness– Recovery or death29

ARS: Prodromal PhaseVaried symptoms:– Nausea, vomiting, diarrhea, mentalstatus changeSymptoms relate to the major organsystems affected by radiation (intestinal,neurovascular, etc.)The earlier the symptoms appear, theworse the prognosis– N/V in < 30 minutes poor prognosis30

ARS: Latent PhaseThe shorter the latent phase, the higher theexposureReduced lymphocyte count may occurwithin 24 hours (so a little delayed) and is agood indicator of radiation dose:> 1,200 = good prognosis300-1,200 = potentially lethal< 300 = critical31

ARS: Manifest IllnessSymptoms relate to the major organsystems affected by radiation (marrow,intestinal, neurovascular)– Think of this as you would patients treated forcancer32

ARS: Death or RecoveryDose Dependent> 1,000 RAD (> 10 Gray, > 1000BCAT’s): death in 72 hours withoutmedical care– >600 BCAT’s in some literature33

Long-Term EffectsAll-oror-nothing:either cancer willdevelop or it willnot34

Effects of acute radiation syndrome vary with dose exposure.35

Dose Effects of Radiation:More Details5-20rem (BCAT): no symptoms20-50: RBC can decline, no symptoms50-100: mild radiation sickness (headache, increased risk infection)100-200: light radiation poisoning with n/v 3-66 hours later, 10% dieafter 30 days200-300: moderate symptoms 1-616 hours later, hair loss, WBC loss,35% die by 30 days300-400: severe poisoning, symptoms ½-2 2 hours, 50% die after 30days400-600: Acute radiation poisoning, >60% die after 30 days(bleeding, infection)600-1000: Acute, severe, 100% mortality if not treated, highmortality even with treatment (think BMT)1000-5000: Acute, severe, symptoms in minutes (skin, etc.), veryhigh mortality even with treatment36

Special Issues forDisaster Teams37

Disaster ResponseIncident Commander sets time limits inexposure areaAll recovery personnel must becounseled about risks involvedOnce a responder’s s maximum radiationlevel has been reached, that person mustleave the site until the general public isallowed admission38

Assess the scene:how much radiation isthere (doseexposure)?– Geiger counts/mindivided by 2.5 millionis about 1 BCAT perhourThis is a VERY roughestimateRemember key isabsorbed radiation (rem(not rad) ) and Geigercounter measures radsMonitoring39

MonitoringKnow the limitations of yourradiation detection devices!– Numbers are estimates!Many radiation detection devicesmeasure only beta and gammaradiation40

MonitoringThe severity ofradiation illness isbased upon thedose of theradiation absorbedDose = exposuretime X dose rate41

Protection from IonizingRadiationThe cardinal rule of protection against radiationis:– TIMEShorter is better– DISTANCEFarther is better– SHIELDINGThe more shielding the better42

Exposure Recommendation forRespondersAs little as possible is best– Faster exposure to high dose is WORSE thanslower exposure to lower dose (even if samecumulative dose obtained)

Decontamination of RadiationCasualtiesDecontaminate before, during, or after initialstabilization, depending on severity of injuryIrradiated casualties DO NOT requiredecontaminationExternally contaminated casualties DO requiredecontamination– Removal of clothing of externallycontaminated casualties eliminates > 90% ofthe contamination44

Triage of Radiation CasualtiesRadiation effects aredelayed—triage is doneaccording to conventionaltrauma protocolsThe earlier that there aresymptoms, the worse theprognosis– N/V < 30 minutes, very poorprognosis– This should be part of thetriage thinking45

Surgical Treatment of RadiationVictimsEmergency surgery, as well asclosure of surgical wounds, should beperformed early in victims of radiationexposureEmergencySurgeryNo surgeryHematopoieticRecoverySurgeryPermitted24-48 hours 3 months After 3 months46

Treatment Limitation Alert!Iodine tablets, often distributed near nuclearreactors, are effective ONLY against effectsof radioactive iodine on the thyroidIodine offers no protection against radiationor other radioactive materialsResponders who may be exposed shouldtake them early to prevent thyroid exposure47

Other TreatmentsDo not forget to treat other issuesSupportive care is key– Think BMTFor internal exposure there are treatmentoptions– Limited to certain agents– Specialized care neededSurgical timing48


More magazines by this user
Similar magazines