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Module 2

Health and Medical Effects

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Health and Medical Effects

Terminal Objective:

DESCRIBE the indicators, signs, and symptoms of exposure to radiation.

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Enabling Objectives:1. LIST the major sources of natural

background and man-made radiation.

2. STATE the average annual dose to the general population from natural background and man-made sources of radiation.

3. DESCRIBE the purposes of radiation dose limits and the guidance for emergency doses.

Health and Medical Effects

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Enabling Objectives (continued):

4. DESCRIBE acute radiation dose and chronic radiation dose and the possible effects of each.

5. STATE the routes of entry by which radioactive material can enter the body.

Health and Medical Effects

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Sources of Natural Background Radiation

• Cosmic Radiation

• Sources in the Human Body

• Sources in the Earth’s Crust

• Radon

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Cosmic Radiation

• Cosmic radiation comes from the sun and outer space.

• At sea level, the average annual cosmic radiation dose is about 26 mrem per year.

• The higher the elevation, the higher the dose of cosmic radiation.

• The exposure increases about 1 mrem per year for every 100 feet up in altitude.

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Terrestrial Radiation

Sources in the Earth’s Crust

• Ground, rocks, soil, and sand

• Sources – natural radioactive elements of radium, uranium, thorium, and potassium

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75

55

40

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Terrestrial Radiation average in continental US: 28 mrem per year

Terrestrial Radiation average in continental U.S.: 28 mrem per year

mrem per year

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Internal Sources of Natural Background Radiation

• Sources in the human body• Food and water in trace amounts• Naturally occurring radioactive

materials deposited in our bodies• Combined exposure from internal

sources – radioactive dose of about 40 mrem per year

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Radon

• (Gas) formed from the radioactive decay of uranium in the soil

• Can collect in basements

• Emits alpha radiation

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Man-Made Sources of Radiation

• Tobacco products

• Medical radiation

• Building materials

• Domestic water supply

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Sources of Radiation

NATURAL BACKGROUND mrem/yearCosmic Radiation 26Terrestrial (Earth’s crust) 28Internal Sources (body) 40Radon 200

MAN-MADE SOURCES mrem/yearSmoking (Tobacco Products) 1300Medical X-rays 40Medical Diagnosis and Therapy 14Building Materials 7Domestic Water Supply 5

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Sources of Radiation

Total of natural background and man-made sources for the average American (non-smoker):

360 mrem per year (about 1 mrem per day)

Average due to smoking cigarettes

(1 pack a day):

1300 mrem per year (about 3 mrem per pack)

Round-trip airline flight across the U.S.:

about 5 mrem

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Biological Effects

QuickTime™ and aCinepak decompressor

are needed to see this picture.

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Effects of Radiation on Cells

• Atoms

• Molecules

• Cells

• Tissues and Organs

• Body

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Effects of Radiation on Cells (cont.)

Some cells are more sensitive:

• Blood

• Cells that form sperm

• Intestinal tract

• Hair follicles

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Effects on Cells Exposed to Ionizing Radiation

• No damage

• Repair and operate normally

• Damaged and operate abnormally

• Cells die

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Inhalation Ingestion

Biological Pathways

Puncture or InjectionAbsorption

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Acute vs. Chronic Radiation Doses

Acute• Large

dose • Short time

Chronic• Small

doses • Long time

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Acute Radiation Dose

Exposure to high doses of radiation over a short period of time

(minutes, hours, days)

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Biological Effects of Radiation Exposure

• Damage in exposed individual

• No proven cases of genetic damage to humans passed on to future children

• Survivors of Hiroshima and Nagasaki: genetic mutations in their children no higher than the general population

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Factors Affecting Cell Damage

• Total dose • Dose rate • Type of radiation • Area of the body• Cell sensitivity • Individual sensitivity • General state of health

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Acute Radiation EffectsDose

Less than 50,000 mrem

• No symptoms

Between 50,000 and 100,000 mrem

• Temporary lowering of white cell count

Between 100,000 and 200,000 mrem

• Hours Later: Nausea, vomiting, diarrhea

• No permanent disability

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Acute Radiation EffectsDose (continued)

Between 200,000 and 450,000 mrem

• Vomiting, diarrhea, hair loss

• 200,000 mrem lethal for 5% people in 60 days

450,000 mrem

• Lethal Dose 50% in 60 days LD50/60

600,000 mrem

• Death for most people

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Radiation Burns

Chernobyl Firefighter

Bronze-coloring, “tanning” of the skin

Cloth

Red-coloring, Swelling, Blistering

Victim from the country of Georgia

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Radiation Burns – Gamma and Beta Radiation

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Beta Burns from Contamination

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Beta Burns on Foot

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Beta Burns from Radioactive Fallout

Healing Skin, 30 Days after Burn

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Hair Loss

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Casualties from a Nuclear Detonation

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Effects of Nuclear Detonation

• Thermal (flash) injuries from thermal pulse

• Shock wave injuries, collapsed buildings

• Radiation burns and sickness

• Injuries from fires

• External/internal contamination

• Long-term effects

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Flash Burns

Thermal Pulse Injury from Nuclear Blast

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Dose (mrem) Percent

1,000 0.08

5,000 0.4

10,000 0.8

25,000 2.0

50,000 4.0

Acute Exposure and Fatal Cancer

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Fatal Cancer Risk Estimates (Example)

• 10,000 mrem dose – extra 0.8%

• 1,000 survivors receive 10,000 mrem – estimated 8 extra cancer deaths

• 200 cancer deaths from other causes

• 208 total cancer deaths

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Chronic Radiation Dose Risks

• A small amount of ionizing radiation received over a long period of time (months, years)

• Small increase in cancer risk

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Estimated Loss of Life Expectancy from Health Risks

Estimated Days Lost

• Smoking one pack a day 2250

• Being 25% overweight 777

• Agricultural accidents 320

• Construction accidents 227

• Automobile accidents 207

• Chronic Radiation

(1000 mrem per year from 18 to 65) 51

• All industry 50

• Chronic Radiation

(100 mrem per year for 70 years) 10

• Medical radiation 6

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EPA Guidelines for Emergency Procedures

Dose Limit:

Maximum radiation dose that a responder is allowed to receive.

Purpose of Dose Limit:

Allow responders to perform emergency actions, yet keep risk as low as possible

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EPA Guidelines for Emergency Procedures*

(expected only once in a lifetime)

* Minors and pregnant females have much lower limits

Dose limitEmergency

Activity PerformedCondition

5,000 mrem All activitiesAll activities during

emergency

10,000 mremProtecting major

propertyWhere lower dose not

practicable

25,000 mremLifesaving or protection

of large populationsWhere lower dose not

practicable

More than 25,000 mrem

Lifesaving or protection of large populations

Only on a volunteer basis to persons fully

aware of the risks involved.

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Health and Medical Effects

1.1. If there are low-level radiation readings, If there are low-level radiation readings, what are the possible sources of what are the possible sources of radiation?radiation?

2.2. How much radiation do you receive How much radiation do you receive daily?daily?

3.3. If there is radiation from the explosion, If there is radiation from the explosion, could it get onto or into your body?could it get onto or into your body?

4.4. What happens if radiation gets into the What happens if radiation gets into the body?body?

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