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Howard Matis - [email protected] Matis - [email protected] 11

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Howard MatisHoward MatisLawrence Berkeley National LaboratoryLawrence Berkeley National Laboratory

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Radiation gives Superhuman Powers to Radiation gives Superhuman Powers to SpidermanSpiderman

QuickTime™ and aTIFF (Uncompressed) decompressor

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Radiation gives Superhuman Powers to Radiation gives Superhuman Powers to The HulkThe Hulk



ChernobylChernobyl



Radiation is Radiation is

Plot device for fictionPlot device for fiction ScaryScary DeadlyDeadly Life savingLife saving MisunderstoodMisunderstood UsefulUseful



Radiation Hazard SymbolRadiation Hazard SymbolThe symbol is placed on a placard with the word CAUTION or DANGER or GRAVE DANGER centered about it. Under the symbol is the information addressing the types of hazards.Examples are:

Radiation Area High Radiation AreaAirborne Radioactivity Area

Contaminated Area

Radioactive Materials Area

R1.5R

5R

60°

60°



Radiation is EnergyRadiation is Energy The energy is given off by unstable (radioactive) The energy is given off by unstable (radioactive)

atoms and some machines.atoms and some machines.

We will be focusing on We will be focusing on ionizing radiationionizing radiation and its health effects. and its health effects.



Atoms Building Blocks of MatterAtoms Building Blocks of Matter

All matter is made up of All matter is made up of atomsatoms

The nucleus is in centerThe nucleus is in center almost all of the massalmost all of the mass

Electrons go aroundElectrons go around At this scale, electrons At this scale, electrons

are at the edge of townare at the edge of town



What is a Nucleus?What is a Nucleus?

Quarks determine if proton Quarks determine if proton or neutronor neutron

NeutronsNeutrons ProtonsProtons Protons determine Protons determine chemical chemical

propertiesproperties Ratio of neutrons to protons Ratio of neutrons to protons

make a nucleus make a nucleus stablestable or or unstableunstable



IsotopesIsotopes•Many elements have nuclei with Many elements have nuclei with the same number of protonsthe same number of protons

•same namesame name

•same chemistrysame chemistry

•but different numbers of but different numbers of neutronsneutrons

•different massesdifferent masses



Examples - IsotopesExamples - Isotopes

•Uranium-238 (238U)

92 protons, 146 neutrons, mass 238

•Uranium-235 (235U)


•Hydrogen (1H)

1 proton, 0 neutrons, mass 1

•Deuterium (2D)

1 proton, 1 neutron, mass 2

•Tritium (31T)

1 proton, 2 neutrons, mass 3

•Helium (4He) (-particle)


•Helium-3 (3He)

2 protons, 1 neutron, mass 3



Types of RadioactivityTypes of Radioactivity

•Each type of radiation is ionizing Each type of radiation is ionizing

•But different propertiesBut different properties

•affect the hazards they poseaffect the hazards they pose

•the detection mechanismthe detection mechanism

•shieldingshielding

Six Common TypesSix Common Types

Alpha DecayAlpha Decay

Beta DecayBeta Decay

Gamma DecayGamma Decay

FissionFission

FusionFusion

Cosmic RaysCosmic Rays



How Does it Decay?How Does it Decay?

AAlpha - lose an alpha lpha - lose an alpha particle (particle ( - helium - helium nucleus)nucleus)

BBeta - emit a beta eta - emit a beta particle (particle ( - electron or - electron or anti-electron)anti-electron)

GGamma - emit a gamma amma - emit a gamma (( or photon or light or photon or light particle)particle)



Alpha DecayAlpha Decay

Alpha particle or helium nucleus Alpha particle or helium nucleus emittedemitted

Nucleus changes mass by four Nucleus changes mass by four units and charge by two unitsunits and charge by two units

Common for heavy elementsCommon for heavy elements Changes chemical propertiesChanges chemical properties Alpha particle easily stoppedAlpha particle easily stopped

4 x nucleon mass4 x nucleon mass +2 Charge +2 Charge BigBig



Beta DecayBeta Decay

Beta minus - neutron converts to Beta minus - neutron converts to electron and anti-neutrinoelectron and anti-neutrino

Beta plus - proton converts to a Beta plus - proton converts to a anti-electron and neutrinoanti-electron and neutrino

Nucleus changes charge but not Nucleus changes charge but not mass numbermass number

Changes chemical propertiesChanges chemical properties Radiation moderately penetratingRadiation moderately penetrating

+1 charge+1 charge Small electronSmall electron





Gamma DecayGamma Decay

Nucleus changes energy Nucleus changes energy levellevel Emits gamma ray or Emits gamma ray or

photonphoton Nucleus stays the sameNucleus stays the same

No change in chemical No change in chemical propertiesproperties

Very penetratingVery penetrating Almost no sizeAlmost no size NeutralNeutral



Absorption of RadiationAbsorption of Radiation++

0-

0

1n

Alpha

Beta

Gamma and X-rays

Neutron

Paper Plastic Lead Concrete



FissionFissionThe heavy parent nucleus The heavy parent nucleus fissions …fissions …

… … into two lighter (radioactive) fission fragment nuclei plus into two lighter (radioactive) fission fragment nuclei plus some left over neutronssome left over neutrons

Sometimes a very heavy Sometimes a very heavy nucleus will fall apart nucleus will fall apart before it can emit an before it can emit an alpha particle.alpha particle.

Fission can release an enormous amount of energy and is Fission can release an enormous amount of energy and is utilized in power plants and fission bombs (A-bomb).utilized in power plants and fission bombs (A-bomb).



FusionFusion

When two nuclei collide and When two nuclei collide and stick togetherstick together

Process that powers the sun Process that powers the sun and starsand stars

All life arises from itAll life arises from it Not usually found in every Not usually found in every

day experience day experience on Earthon Earth Component of the H-bombComponent of the H-bomb



How Unstable Is It?How Unstable Is It? The The “Half-life”“Half-life” describes how quickly Radioactive Material describes how quickly Radioactive Material

decays away with time.decays away with time.

It is the time required for It is the time required for halfhalf of the unstable atoms to decay. of the unstable atoms to decay.

Some Examples:Some Examples: Some natural isotopes (like uranium and thorium) have half-lives that Some natural isotopes (like uranium and thorium) have half-lives that

are billions of yearsare billions of years Since Earth is about 5 billion years old, short lived naturally produced Since Earth is about 5 billion years old, short lived naturally produced

isotopes goneisotopes gone Most medical isotopes (like Most medical isotopes (like 99m99mTcTc) last only a few days) last only a few days



Half-Life ExperimentHalf-Life Experiment

Guess the number I am thinkingGuess the number I am thinkingfrom 1 to 4from 1 to 4



Some Isotopes & Their Half LivesSome Isotopes & Their Half LivesISOTOPEISOTOPE HALF-HALF-

LIFELIFEAPPLICATIONSAPPLICATIONS

238238U – UraniumU – Uranium billions billions of yearsof years

Natural uranium is comprised of several different isotopes. Natural uranium is comprised of several different isotopes. When enriched in the isotope of When enriched in the isotope of 235235U, it’s used to power U, it’s used to power nuclear reactor or nuclear weapons. nuclear reactor or nuclear weapons.

1414C – CarbonC – Carbon 5730 y5730 y Found in nature from cosmic interactions, used to “carbon Found in nature from cosmic interactions, used to “carbon date” items and as radiolabel for detection of tumors.date” items and as radiolabel for detection of tumors.

137137Ce – CesiumCe – Cesium 30.2 y30.2 y Blood irradiators, tumor treatment through external Blood irradiators, tumor treatment through external exposure. Also used for industrial radiography.exposure. Also used for industrial radiography.

33H – TritiumH – Tritium 12.3 y12.3 y Labeling biological tracers.Labeling biological tracers.

192192Ir – IridiumIr – Iridium 74 d74 d Implants or "seeds" for treatment of cancer. Also used for Implants or "seeds" for treatment of cancer. Also used for industrial radiography.industrial radiography.

9999Mo – Mo – MolybdenumMolybdenum

66 h66 h Parent for Parent for 99m99mTc generator.Tc generator.

99m99mTc – Tc – TechnetiumTechnetium

6 h6 h Brain, heart, liver (gastroenterology), lungs, bones, thyroid, Brain, heart, liver (gastroenterology), lungs, bones, thyroid, and kidney imaging, regional cerebral blood flow, etc.and kidney imaging, regional cerebral blood flow, etc.



How do we Measure the Amount of How do we Measure the Amount of Radiation?Radiation?



Radiation Quantities and UnitsRadiation Quantities and Units

RadioactivityRadioactivityQty: ActivityQty: ActivityUnit: Curie (Bequerel)Unit: Curie (Bequerel) 1 Ci = 1000 mCi1 Ci = 1000 mCi 1 Bq = 1 disintegration/sec1 Bq = 1 disintegration/sec 1 Ci = 3.7 1 Ci = 3.7 10 101010 Bq Bq

Radiation RiskRadiation RiskQty: Dose EquivalentQty: Dose EquivalentUnit: rem (Sievert)Unit: rem (Sievert) 1 rem = 1000 mrem1 rem = 1000 mrem 1 Sv=100 rem1 Sv=100 rem

Radiation Absorbed DoseRadiation Absorbed DoseQty: DoseQty: DoseUnit: rad (Gray)Unit: rad (Gray) 1 rad = 1000 mrad1 rad = 1000 mrad 1 rad = 100 erg/gram1 rad = 100 erg/gram 1 Gy =100 rad1 Gy =100 rad

Roentge

n

equivalent

man



Convert from Curies to RadConvert from Curies to Rad

Curie is the number of decays/sCurie is the number of decays/s 1 Curie = 3.7 1 Curie = 3.7 10 101010 decays/s (exactly) decays/s (exactly)

Rad is the absorbed dose or physical doseRad is the absorbed dose or physical dose Amount of energy deposited in unit massAmount of energy deposited in unit mass

human tissue or other mediahuman tissue or other media 1 Rad = 100 erg/g1 Rad = 100 erg/g

Often use grayOften use gray 1 J/kg1 J/kg 1 gray = 100 rad1 gray = 100 rad



Need Biological Dose – REMNeed Biological Dose – REM

rad rad Q = rem Q = rem

QQ

Gamma x-rayGamma x-ray 11

BetaBeta 11

NeutronNeutron 3-203-20

AlphaAlpha 2020

•To convert from rad to rem multiply by appropriate value of Q

•Q is the Quality Factor

•Q reflects the damage



Radiation and HealthRadiation and Health

Does radiation affect you?Does radiation affect you?



Ionizing Radiation can Damage DNAIonizing Radiation can Damage DNAIonizing radiation has Ionizing radiation has the ability to ionizethe ability to ionize** atoms and molecules, atoms and molecules, possibly altering possibly altering structure and function.structure and function.

* ionize = produce* ionize = produce positive and negative positive and negative electrical chargeelectrical charge



Alpha Radiation Is Only a Hazard When Alpha Radiation Is Only a Hazard When Inside Your Body (Internal Hazard)Inside Your Body (Internal Hazard)

Your skin will stop it

can’t penetrate skin internal hazard

stopped by paper

found in soil, radon and other radioactive materials



Beta Radiation Is a Skin, Eye and Internal Beta Radiation Is a Skin, Eye and Internal HazardHazard

skin, eye and internal hazard

stopped by plastic

found in natural food, air and water



X-ray and Gamma Radiation Are Penetrating X-ray and Gamma Radiation Are Penetrating Radiation and an Radiation and an External HazardExternal Hazard

stopped by lead

naturally present in soil and cosmic radiation

found in medical uses



How does Radiation Injure Cells?How does Radiation Injure Cells?

•High energy radiation breaks chemical bonds.

•This creates free radicals, like those produced by other insults as well as by normal cellular processes in the body.

•The free radicals can change chemicals in the body.

•These changes can disrupt cell function and may kill cells.

+

-



Types of Exposure & Health EffectsTypes of Exposure & Health Effects Acute Dose - DeterministicAcute Dose - Deterministic

Large radiation dose in a short period of timeLarge radiation dose in a short period of time Large doses may result in observable health effectsLarge doses may result in observable health effects

Early: Nausea & vomitingEarly: Nausea & vomiting Hair loss, fatigue, & medical complicationsHair loss, fatigue, & medical complications Burns and wounds heal slowlyBurns and wounds heal slowly

Examples: medical exposures andExamples: medical exposures andaccidental exposure to sealed sourcesaccidental exposure to sealed sources

Chronic Dose - StochasticChronic Dose - Stochastic Radiation dose received over a long period of time Radiation dose received over a long period of time Body more easily repairs damage from chronic doses Body more easily repairs damage from chronic doses Does not usually result in observable effectsDoes not usually result in observable effects Examples: Background Radiation andExamples: Background Radiation and

Internal DepositionInternal Deposition Inhalation



At HIGH Doses, We KNOW Radiation At HIGH Doses, We KNOW Radiation Causes HarmCauses Harm

High Dose effects seen inHigh Dose effects seen in Radium dial paintersRadium dial painters Early radiologistsEarly radiologists Atomic bomb survivorsAtomic bomb survivors Populations near ChernobylPopulations near Chernobyl Medical treatmentsMedical treatments Criticality AccidentsCriticality Accidents

CancerCancer Leukemia (A-bomb data)Leukemia (A-bomb data) Thyroid (Chernobyl data)Thyroid (Chernobyl data) Bone and other solid cancers (A-bomb data)Bone and other solid cancers (A-bomb data)

Birth defectsBirth defects (A-bomb data) (A-bomb data) Genetic effectsGenetic effects (only animal data) (only animal data)..



Effects of ACUTE (Deterministic) Exposures

Dose (rads*)Dose (rads*) EffectsEffects

25-5025-50First sign of physical effectsFirst sign of physical effects (drop in white blood cell count)(drop in white blood cell count)

100100Threshold for vomiting Threshold for vomiting (within a few hours of exposure)(within a few hours of exposure)

320 - 360320 - 360 ~ 50% die within 60 days ~ 50% die within 60 days (with minimal supportive care)(with minimal supportive care)

480 - 540480 - 540~50 % die within 60 days~50 % die within 60 days(with supportive medical care)(with supportive medical care)

1,0001,000 ~ 100% die within 30 days ~ 100% die within 30 days

* For common external exposures 1 rad ~ 1 rem = 1,000 mremFor common external exposures 1 rad ~ 1 rem = 1,000 mrem



At LOW Doses, We At LOW Doses, We PRESUMEPRESUME Radiation Causes Radiation Causes HarmHarm

No physical effects have been observedNo physical effects have been observedThe Bad News:The Bad News: Radiation is a carcinogenRadiation is a carcinogen

and a mutagenand a mutagen

The Good News: The Good News: Radiation is a Radiation is a very weakvery weakcarcinogen and mutagen!carcinogen and mutagen!

Very Small DOSE = Very Small RISK



Sources of RadiationSources of Radiation

Average Average radiation radiation exposure in the exposure in the United States United States 360 mrem or360 mrem or 0.360 rem0.360 rem

Very location Very location dependentdependent



Manufactured Sources of Radiation Contribute an Manufactured Sources of Radiation Contribute an Average of 60 mrem/yearAverage of 60 mrem/year

cigarette smoking - 1300 mremcigarette smoking - 1300 mrem lung doselung dose

building materials - 3.6 mrembuilding materials - 3.6 mrem

smoke detectors - 0.0001 mremsmoke detectors - 0.0001 mrem

medical - 53 mremmedical - 53 mrem



Risks in PerspectiveRisks in Perspective

1 in 1 million chance of 1 in 1 million chance of fatalityfatality 40 tablespoon peanut butter (aflotoxin)40 tablespoon peanut butter (aflotoxin) 2 days in New York City (air quality)2 days in New York City (air quality) 3 mrem radiation (cancer)3 mrem radiation (cancer) 1 mile on motorcycle (collision)1 mile on motorcycle (collision) 300 miles in car (collision)300 miles in car (collision) 10 charbroiled steaks10 charbroiled steaks Smoking 1 cigaretteSmoking 1 cigarette



ALARAALARA

Reduce radiation dose by using:Reduce radiation dose by using: TimeTime DistanceDistance ShieldingShielding

ALARAALARA stands for stands for AAs s LLow ow AAs s RReasonably easonably AAchievablechievable



Reduce TimeReduce Time

Spend as short as time as necessary Spend as short as time as necessary to complete the taskto complete the task



ActivityActivity

Demonstrate Time – (t)Demonstrate Time – (t)

€

Dose = ct



Increase DistanceIncrease Distance

Twice the distance = ¼ of the doseTwice the distance = ¼ of the dose



ActivityActivity

Demonstrate Distance – (d)Demonstrate Distance – (d)

€

Dose = cd2



Use ShieldingUse Shielding



ActivityActivity

Demonstrate Shielding – (s)Demonstrate Shielding – (s)

€

Dose = c(1− s)



Reactors Glow in the DarkReactors Glow in the Dark

Reactor core emits Reactor core emits electronselectrons

Electrons move faster Electrons move faster than the speed of light than the speed of light in waterin water

At that speed they emit At that speed they emit blue light blue light Cherenkov RadiationCherenkov Radiation

Similar to sonic boom Similar to sonic boom or wake of a boator wake of a boat



Can You Glow in the Dark?Can You Glow in the Dark? Ingest a very hot radiation sourceIngest a very hot radiation source

Beta neededBeta needed Short half lifeShort half life

Do not swallowDo not swallow Unless your midriff is exposedUnless your midriff is exposed

Or inject source into your bloodOr inject source into your blood Don’t be in direct lightDon’t be in direct light

Usually too faint for sunlightUsually too faint for sunlight

Try it for Halloween?Try it for Halloween?



SummarySummary

Radiation is partRadiation is part Our natural environmentOur natural environment TechnologyTechnology

Health effectsHealth effects Known for high dosesKnown for high doses Unknown for lowUnknown for low

You deal with it You deal with it regularlyregularly



The EndThe End

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