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Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation Science Teacher Workshop University of Richmond Richmond, VA July 18, 2007
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Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Dec 24, 2015

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Page 1: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Biological Effects of Ionizing Radiation

Biological Effects of Ionizing Radiation

Science of Nuclear Energy and Radiation

Science of Nuclear Energy and Radiation

Carl A. Tarantino, CHPCorporate Health Physicist

Dominion Generation

Science Teacher WorkshopUniversity of Richmond

Richmond, VAJuly 18, 2007

Science Teacher WorkshopUniversity of Richmond

Richmond, VAJuly 18, 2007

Page 2: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Radon

X-Rays

ConsumerProducts

NuclearPower

RadioactiveWaste

Nuclear Medicine

Solar Radiation Cosmic Rays

TerrestrialRadiation

Food &Drink

Each Other

Radiation in LifeRadiation in Life

Page 3: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Ionizing Radiation UnitsIonizing Radiation Units

Old Units SI Units What It Is

1 C kg-1 = 3876 R

rad Gray

1 Gy = 100 rad

rem Sievert

1 Sv = 100 rem

Page 4: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Measuring Radiation EffectsMeasuring Radiation Effects

How much radiation is produced– Activity: decays per time (Curie (Ci), Becquerel (Bq))

How much energy absorbed by tissue– Dose

How much biological damage does the radiation do per energy absorbed

– Dose equivalent

Page 5: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Ionizing Radiation EffectsIonizing Radiation Effects

Absorption of Radiation

Ionization

Chemical Change

Repair or Damage

High Dose EffectsCell killingTissue or organ effectsWhole body effects

Low Dose EffectsMutationsCancerEffects to unborn

Page 6: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Cellular OrganizationCellular Organization

Page 7: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Potential Radiation Damage to DNA

Potential Radiation Damage to DNA

Most critical molecule within humans: DNA Direct effect

on molecule by ionization or excitation of the molecule and subsequent dissociation of the molecule

Page 8: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Other Damage to DNAOther Damage to DNA

Many other entities cause breaks in DNA – Temperature, chemicals, etc.

Human DNA suffer millions of DNA breaks daily– Most repaired

Page 9: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

H2O

H2O+

e-H+

H2O2

OHo

HO2

OH-Ho

H2

WATERWATER

Radiation Induced Decomposition of Water

Within a Cell

Radiation Induced Decomposition of Water

Within a Cell

Incoming Radiation

Production of free radicals within the cell can result in indirect effects

Most abundant molecule within humans: Water

Page 10: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Potential Outcomes of Radiation

Damage to Parent Cells

Potential Outcomes of Radiation

Damage to Parent Cells

Page 11: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Cell Repair after Chronic Dose Damage

Cell Repair after Chronic Dose Damage

Time

Rad

iati

on

Dose

Accumulated Irreparable

Reparable

Page 12: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Cellular Radiosensitivity:Law of Bergonie and

Tribondeau

Cellular Radiosensitivity:Law of Bergonie and

Tribondeau

The basic law of Bergonie and Tribondeau is that young and rapidly dividing cells are more sensitive than cells with adult development. Cells tend to be radiosensitive if they have three properties:

»Cells that have high division rate(the time between divisions)

»Cells that have long dividing future

(immature cells in early cellular life)

»Cells that are unspecialized(cells which have a widely diverse future)

Page 13: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Relative Sensitivity of Cell and Tissue Types

Relative Sensitivity of Cell and Tissue Types

Lymphocytes Spermatogonia Hematopoietic (Blood

Forming) Intestinal Epithelium Skin Nerve Cells Muscle Tissue Bone Collagen

Page 14: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Hematological Response 1 Sv (100 rems)

Page 15: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Hematological Response 3 Sv (300 rems)

Page 16: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Possible Radiation Dose Response Curves

Possible Radiation Dose Response Curves

1- Linear (Non-Threshold)2 - Linear-Quadratic3 - Threshold4 - Supralinear

Dose (rem)

Eff

ects

Most conservative model: An increase in dose results in a proportional increase in risk

At low doses there is only a slight increase in risk that becomes proportional to dose at higher doses

There is a threshold for dose response at which lower doses do not result in increased risk

At low doses there is a higher risk that becomes proportional to dose at higher doses

Hormesis model (not shown): Low doses of radiation have a positive effect and decrease risk

Page 17: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

HormesisHormesis

Some data indicate that low doses of radiation are beneficial

Not widely accepted– Conservative is better

But not impossible

Dose

Detr

iment

Benifi

cialRis

k

Page 18: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Risk TermsRisk Terms

A large dose of radiation in a short period of time

Small doses of radiation protracted over a long period of time

Health effects that occur randomly and for which the probability of the effect occurring, rather than its severity, is assumed to be a linear function of dose without threshold

Health effects which do not appear until a threshold value is exceeded and for which the severity of the effect increases with dose beyond the threshold

Effects which occur in the exposed individual

Effects which occur in the progeny of the exposed individual due to chromosome aberrations in the parent

Effects to the unborn fetus irradiated in-utero

Acute

Chronic

Stochastic

Non-stochastic

Somatic

Genetic

Teratogenic

Page 19: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Risk ExamplesRisk Examples

Hereditary effects Cancer (leukemia,

tumors) Erythema (skin

reddening) Cataracts Sterility Epilation (hair loss) Hematological effects

Genetic; stochastic

Somatic; stochastic

Somatic; non-stochastic

Somatic; non-stochastic

Somatic; non-stochastic

Somatic; non-stochastic

Somatic; non-stochastic

Page 20: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Biological Effects from Low Doses of RadiationBiological Effects from

Low Doses of Radiation

Biological effects from low doses potentially occur due to chronic exposures. A chronic exposure occurs when a relatively small amount of radiation is absorbed by tissue over a long period of time.

Under 5 rad of exposure - No detectable health effects in exposed individual

Chronic exposures result in an increased risk in latent adverse health effects

Health effects could be genetic effects or somatic effects

Page 21: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Latency PeriodLatency Period

Time (years)

Ris

k

Time radiation dose received

Latent period

Period at risk

Risk curve

0 4 30

Leukemia latency and time at risk periods

Latency period is the time from time of exposure until the effect is exhibited

Radiation exposure does not produce cancer in every exposed person

Effects can be immediate or years later for acute, high-level exposures

Page 22: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Biological effects from high doses occur due to acute exposures. An acute exposure occurs when a relatively large amount of radiation is absorbed by tissue over a short period of time; effects can occur in the short term and long term.

Biological Effects from High Doses of RadiationBiological Effects from High Doses of Radiation

Hematopoietic Syndrome: (100-200 rad or 1-2 Gray) Early symptoms are anorexia, nausea, and vomiting followed by a phase of bone marrow depression and subsequent susceptibility to infection. After several weeks, death may occur.

Gastrointestinal Syndrome: (700-1000 rad or 7-10 Gray) Early symptoms are anorexia, nausea, and vomiting followed by fever, diarrhea, and electrolyte imbalance due to ulceration of the intestinal wall. Once GI system ceases to function, death will occur.

Central Nervous System Syndrome: (2000-5000 rad or 20-50 Gray) Symptoms occur very quickly and the brain and muscles can no longer control bodily functions, including breathing and blood circulation. Death within hours or within several days.

Page 23: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Effects From Acute, High-level Radiation DosesEffects From Acute, High-level Radiation Doses

Dose (rad)

0 - 100 100 - 200 200 - 600 600 - 1000 1000 - 5000 Over 5000

Incidence ofVomiting

None100 rad: 5%

200 rad: 50%300 rad:

100%100% 100% 100%

Time of Onset ------ 3 hr. 2 hr. 1 hr. 30 min. 30 min.

PrincipalAffected Organs

None Hematopoietic tissueGastrointestinal

tract

Centralnervoussystem

CharacteristicSigns

NoneModerate

leukopenia

Severe leukopenia; purpura;hemorrhage; infection;epilation above 300 rad

Diarrhea; fever;disturbance of

electrolytebalance

Convulsion;tremor;ataxia;

lethargy

Critical PeriodPost Exposure

------ ------ 4 to 6 weeks 45 to 14 days 1 to 48 hrs.

Prognosis Excellent Excellent Good Guarded Hopeless Hopeless

ConvalescentPeriod

NoneSeveralWeeks

1 to 2 months Long ------ ------

Incidence ofDeath

None None0 to 80%(variable)

80 to 100%(variable)

90 to 100% 90 to 100%

Death OccursWithin

------ ------ 2 months 2 weeks 2 days

Cause of Death ------ ------ Hemorrhage; infectionCirculatory

collapse

Respiratoryfailure; brain

edema

Page 24: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Median Lethal Dose CurveMedian Lethal Dose Curve

Dose (rad)

LD50 - Median Lethal Dose

LD50/30 - Lethal dose to 50% of exposed population

within 30 days of irradiation, without medical attention Defined at approximately 450 rad

Page 25: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

What is Safe?What is Safe?

Driving a car is “safe”– 1:6,000

Living at home is “safe”– Falls -- 1:20,000– Fires -- 1:50,000– Poisoning -- 1:40,000– Total -- 1:10,000

Radiation (1 mSv) is safe– 1:20,000

Page 26: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

10.96

10.00

6.16

4.50

4.40

3.42

3.15

2.85

2.33

2.20

0.57

0 2 4 6 8 10 12

Alcoholic

Poverty

Smoking-Male

No Friends

Heart Disease

Cancer

High Risk Job

20% Overweight

H.S. Drop-Out

Orphan

Car Accidents

Years

Relative Risk:Years of Life Lost

Relative Risk:Years of Life Lost

Page 27: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Relative Risk:Days of Life Lost

Relative Risk:Days of Life Lost

207130

11593

7755

5050

30242322

209.3

7

0 50 100 150 200 250

Car Accidents

Alcohol

Suicide

Murder

Air Pollution

AIDS

Energy Conservation

Spouse Smoking

Radon

Drowning

Radiation Worker

Drinking Water

Fire, Burns

Natural Radiation

Natural Hazards

Days

Page 28: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

168

148.8

144

108

60

48

24

21.6

8

3

1.2

0 20 40 60 80 100 120 140 160 180

Natural Hazards

Medical Radiation

Bicycles

Electrocution

Hazardous Waste

Nuclear Power

Peanut Butter

Milk

Live Near Nuc Plant

Broiled Steaks

Nuclear Power

Hours

Relative Risk:Hours of Life Lost

Relative Risk:Hours of Life Lost

Government

Anti-nuclear activists

Page 29: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Summary of Ionizing Radiation Effects

Summary of Ionizing Radiation Effects

All radiation may not be harmful– However, data does not contradict the

linear, non-threshold theory for some effects (cancer, genetic effects)

Effects from high doses are known fairly well– Depending upon dose, radiation may affect

various cells, tissues, and organs– Without medical treatment, about 50% of

people exposed to approximately 450 rad of radiation are expected to die within 1-2 months

– Acute (short-term) effects below 100 rad are relatively minor

Page 30: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Summary of Ionizing Radiation Effects

Summary of Ionizing Radiation Effects

Effects from low doses occur less frequently and take longer to develop than high dose effects– Studies of populations chronically exposed to

low levels of radiation have not shown conclusive evidence of increased cancer risk

– The magnitude of the risk is inferred from data at higher doses

– The lower the dose of radiation, the longer it takes for the cancer to develop

– Some changes in blood have been detected down to several rad

Page 31: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

Summary of Ionizing Radiation Effects

Summary of Ionizing Radiation Effects

Genetic effects have not been detected in people– Genetic effects may occur, but at rates

so low that they have not been detected over the rate that occurs in the absence of radiation

The unborn child and young children appear to be more sensitive to the effects of radiation than adults are– The rate that effects occur is very low

Page 32: Biological Effects of Ionizing Radiation Science of Nuclear Energy and Radiation Carl A. Tarantino, CHP Corporate Health Physicist Dominion Generation.

The EndThe End