Center for Health Sciences
Welcome To Radiation
Safety Training
OSU Radiation Safety Program
The OSU-CHS radiation safety program will be
conducted in such a manner so that exposure to
faculty, staff, students, the public, and the
environment will be maintained as low as
reasonably achievable and that no radiation
exposure will be received without societal benefit.
This will be accomplished without impeding
legitimate research, or realistic teaching objectives
in accord with State and Federal regulations.
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Chernobyl
Atomic Bomb
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Radiation Environment
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Natural Sources
• Cosmic
• Terrestrial
• Internal
• Inhaled
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Cosmic Radiation
• High energy particles and
photons from the sun and
other sources outside the
earth's atmosphere
– Atmosphere provides
shielding from cosmic
radiation
– An increase in altitude results
in an increase in exposure
(measured in millirem)
– 26 mrem/yr @ sea level
50 mrem/yr in Denver
.5 mrem/hr @ 39,000 feet
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Terrestrial Radiation
• Radiation from radioactive
materials occurring naturally
in the earth’s crust
– Lowest on the Atlantic coast
(16 mrem/yr)
– Highest on eastern slopes of
the Rockies (63 mrem/yr)
– About 30 mrem/yr in the
remainder of the U.S.
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Inhaled Radiation
• Primarily Radon (Rn-222) and its daughters
– Rn-222 is released from the soil as Radium-226
decays
– Radium is part of Uranium-238 decay chain
– Levels vary widely from area to area
– Average dose is 200 mrem/yr
– May be enhanced by poor ventilation or the use of
Uranium containing building materials
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Internal Radiation
• Radiation from radioactive materials
incorporated in the human body
– Primarily Carbon-14 (C-14) and
Potassium-40 (K-40)
– Total dose of 39 mrem/yr (due mostly to K-40)
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Man-Made Sources
• Medical Uses
• Consumers Products
• Industrial Uses
• Nuclear Power
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Medical Sources
• Diagnostic X-ray
• Nuclear Medicine
– General
Radiography
– Dental Radiography
– Fluoroscopy
– CT
– Etc.
39 mrem/yr – U.S. average
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– Imaging using I-131,
Tc-99m, Tl-201
– Therapy using I-131
14 mrem/yr – U.S. average
Medical Sources (cont.)
• Radiation Therapy
– Use of external beams and sealed sources
for treatment of cancers
2.3 mrem/yr – U.S. average
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Industrial Sources
• Industrial Radiography • Well Logging
– Use of X-rays or sealed
gamma-ray sources for
imaging structures and
components
• Level Gauges
― Use of sealed sources
to check the level of
materials in a tank or
vat.
– Use of sealed sources
to measure soil
porosity, soil density, or
underground structure
& composition
• Static Elimination
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– Use of radiation to
remove static electricity
Nuclear Power
• Doses are calculated for maximally exposed member
of the general public
• Uranium Mines = 26-61 mrem/yr
• Processing = 1-8 mrem/yr
• Nuclear Power Plants = < 1 mrem/yr
• Waste Storage = < 1 mrem/yr
• Transportation = 20 mrem/yr
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Consumer Products
• Smoke Detectors (Am-241)
• Tobacco Products
(Pb-210 & Po-210)
• Building Materials
(Sheetrock; gypsum board)
• Airport Baggage
Inspection – (x-rays)
• Welding Rods
(Thorium)
• Luminous Paints for
watch and instrument
dials
(H-3, Ra-226, Pm-147)
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Consumer Products (cont.)
• Television and VDT
(Low energy x-rays)
• Radium Hot Springs
(Ra-226, Rn-222)
• Fiesta-ware
(Uranium oxide coating)
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Contributions to the Public Dose*
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