Basic Radiation Training for Responders to

Radiological Incidents

BASICS OF RADIATION

MA Department of Public Health-Radiation Control Program

Thomas F. O’Connell

Telephone: 617.983.6891

email: thomas.f.o’connell@state.ma.us

July 2002

MA Department of Public Health

Radiation Control Program

174 Portland Street, 5th Fl. Boston, MA

617.727.6214

Emergency Line

617.727.9710

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Nucleus

Neutrons

Protons

Electrons(Electron Clouds)

Structure of the Atom

Decay

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4He NucleusEjected from Nucleus

has a discrete energy that can be measured and related to the parent

Most of the energyassociated with

Decay

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Either too many neutrons or too many protons

Take away + charge and change a proton into a

neutron

Take away - charge and change a neutron into a proton

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antineutrino

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neutrino

Three products share energy – therefore beta has a continuous range of energies

Decay• Emission of a photon from the nucleus• Often occurs after or when nucleus is in an excited state• Given off with discrete energies• Can measure photon energy and possibly identify parent

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neutrino

Gamma Photon

Half-Life Illustration

At = Aoe-t or Nt= Noe- t

Beginning Activity or Number of Nuclei

Time (t)Act

ivity

(A

) or

Num

ber

of N

ucle

i (N

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How fast the curve changes (short half-life) (long half-life)

Radiation by Numbers

Radioactivity Absorbed Dose Dose Equivalent Exposure

Common Units curie (Ci) rad rem Roentgen (R)

SI Units becquerel (Bq) gray (Gy) sievert (Sv) coulomb/kilogram (C/kg)

Conversion Equivalence

1 curie = 3.7 x 1010 disintegrations per sec. 1 becquerel = 1 disintegration per sec.

1 millicurie (mCi) equal 37 megabecquerels (MBq)

1 rad equal 0.01 gray (Gy)

1 rem equal 0.01 sievert (Sv)

1 roentgen (R) equal 0.000258 coulomb/kilogram (C/kg)

megabecqerel (MBq) equal 0.027 millicuries (mCi)

1 gray (Gy) equal 100 rad

1 sievert (Sv) equal 100 rem

1 coulomb/kilogram (C/kg) equal 3,876 roentgens (R) Conversion Factors

To Convert From To Multiply By

curies (Ci) becquerels (Bq) 3.7 x 1010

millicuries (mCi) megabecquerels (Mbq) 37

microcuries (µCi) megabecquerels (Mbq) 0.037

millirads (mrad) milligrays (mGy) 0.01

Millirems (mrem) microsieverts (µSv) 10

milliroentgens (mR) microcoulombs/kilogram (µC/kg) 0.258

becquerels (Bq) curies (Ci) 2.7 x 10-11

megabecquerels (Mbq) millicuries (mCi) 0.027

megabecquerels (Mbq) microcuries (µCi) 27

milligrays (mGy) millirads (mrad) 100

microsieverts (µSv) millirems (mrem) 0.1

microcoulombs/kilogram (µC/kg) milliroentgens (mR) 3.88

• Time:reduce time spent in radiation area

• Distance:stay as far away from the radiation source as possible

• Shielding:interpose appropriate materials between the source and your body

Three Steps for Reducing Radiation Exposure

Shielding for , and

BASIC CONCEPT is to:

Place materials between the source and person to absorb some or all of the radiation

radiation: no shield required for external exposures; clothing, dead skin layer stops ’s,

radiation: ranges of meters in air; some can penetrate dead skin layer; thin plexiglass shields adequate, bunker gear effective for low energy

x and radiation: highly penetrating, best shields are dense materials (lead), vehicles can be used as shields

Shielding for , and

Control of DistanceRemote Operation

manipulating devices, remote handling tools

Moving Away from Sourcesremain near a source only when necessary

treat medical needs of patient/victim first

Secure and Remove Other Radiation Sourceswaste containers at Hot Zone/Cold Zoneother unnecessary sources

Control of distance

Control of Time

• Practice Mission in Background/Low Dose Area

• Spend Down Time in Low Dose Location

• (Dose Rate)(Time) = Dose• 10 mR/hr x ½ Hour = 5 mR• Use Respirators to Minimize

Internal Intake

Good Practices Include:

Restrict AccessLimit PersonnelPost AreasPost ProceduresBuddy System

Be Aware of Your Radiation Environment

Methods for Controlling External Exposure

Decontamination

To Make Safe by Removing the Unwanted Materials

Chemical Decon Techniques Work for Radioactive

Most Radioactive Contamination is on Surfaces

Removal of Outer Clothing is Very Effective

Remove Clothes and Wrap Patient in Sheets

Enforce Clean Zones and Hot Zones

Decontamination

INTERNAL RADIATION EXPOSURE

Radioactive Material Deposited in the Body

Pathways

Inhalation of Dust, Mists or FumesIngestion of Contaminated Food or Water

Injection Via Puncture WoundAbsorption Through Skin or Via a Wound

Internal Radiation Exposure

Internal Radiation Exposure

Rarely any method to reduce exposure once in the body•ILong physical and biological half-life, may irradiate

individual for rest of lifeEstimates of dose are complex

Metabolism

Complex biological process of elimination and concentration

High biological variability

Fraction of energy released deposited in other organs

Internal Radiation Exposure

part 2

At low doses, Radiation Injury is a Statistical Probability

In all cases, the effects of radiation injury will be delayed

Somatic and genetic effect of low level radiationstochastic and non stochastic biological effects

Primary biological effect of radiation is cancer.

Radiation Syndromes and Injury

The more frequently cells divide, the more sensitive they are to radiation injury. The more specialized the cells are, the less sensitive they

are to radiation injury.

Radiation Syndromes and Injury

Between 0 and 100 radsGenerally there is no clinically observable changes

Some nausea at the high end of range in more susceptible personsSome blood changes above 25 rads

100 - 400 radsThe hematopoietic system is affected

Blood cell precursors are very radiosensitiveGradual depression in blood count over days or weeksIncreased susceptibility to infection and hemorrhage

Most recover at lower end of range with some medical care

Acute Radiation Syndromes(VERY HIGH DOSES-Short Time Frame)

400-1400 radsGastrointestinal system is affected

Cells lining the intestinal track are radiosensitiveBacteria and toxic material gain entry into the bloodstream

Diarrhea, dehydration, infection, toxemiaSurvival is unlikely at the upper end of range

Above 1400 radsCardiovascular and Central Nervous System is affected

Blood supply is impaired leading to nausea, vomiting, convulsions,or unconsciousness. There is no hope for survival

LD 50/30 is approximately 450 rads with modest medical treatement

Acute Radiation Syndromes(continued)

Average Annual Exposure

Relative Risk

Relative risk of 1-in-a-million chances of dying :

• Smoking 1.4 cigarettes ( Lung cancer )

• Spending 2 days in New York City ( Air pollution )

• Driving 40 miles in a car ( Fatal crash )

• Flying 2,500 miles in a jet ( Fatal crash )

• Canoeing for 6 minutes ( Drowning )

• Receiving 40 mrem of radiation ( Cancer )

Risk Perspective

Loss of life expectancy (in days due to various causes :

• Construction worker • Driving a small car • Being an unmarried female• 25 % overweight • Coffee • Smoking one pack a day • Being an unmarried male • All industry • Radiation (100 mrem/yr -70 yrs) • Alcohol (U.S. average)

Risk Perspective

Loss of life expectancy (in days due to various causes :

• Being an unmarried male 3500 (10 years)• Smoking one pack a day 2250 ( 7 years)• Being an unmarried female 1600 ( 5 years)• 25 % overweight 777 ( 2 years)• Alcohol (U.S. average) 365 ( 1 year)• Driving a small car 290• Construction worker 227• All industry 60• Radiation (100 mrem/yr -70 yrs) 10• Coffee 6

Nuclear Weapon Effects

Nuclear

Weapons

Effects

Heat, Blast, Pressure

Heat, Blast, Pressure

Heat, Blast, Pressure

Deposition of Radioactive Materials

Small Nuclear Devices

                                 

The Dirty Bomb

• Radiological Dispersal Device (RDD)– Conventional Explosive and Radioactive Material

• Small Localized and Widely Dispersed Scenarios– Dispersal Potential Depends of Physical Form of RAM– Amount of Explosive and Local Weather Drives Dispersion

• Low Level Exposures and Contamination Likely

• Large Psychosocial Effects - Fear Factor

MAP

Radiation Signs

Radiation Signs

Respe

ct radiation

Training

• To Contact NIAT During Office Hours– MA Radiation Control Program

• 617.727.9710

• Off Hours Through– MA State Police

• 508.820.2121

Nuclear Incident Advisory Team

Contact NIAT

Questions?