Radiation Safety
Dr. LeeAnn Pack
Diplomate ACVR
www.upei.ca/~vetrad
www.upei.ca/~vetrad
Radiation Safety
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All radiation is harmful
Learn to protect ourselves
Monitor our exposure
Make our practices safe while providing
diagnostic images to help us treat our
patients
www.upei.ca/~vetrad
ALARA
 National Council on Radiation
Protection
– Publishes recommendations for radiation
limits
 Most groups follow their guidelines
 As Low As Reasonably Achievable
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Roentgen
 First quantitative unit used to measure
exposure.
 It indicates the capacity of radiation to
ionize (energy of radiation can remove
electrons from atoms) air. Roentgen (R)
measures the quantity of ionization
produced by X- or gamma radiation.
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Radiation Absorbed Dose
(Rad)
 Quantity of radiation energy removed
from the x ray beam by an absorbing
material
 1 rad = 100 ergs of ionizing energy per
1 gram of tissue
 SI unit = Gray (Gy) = 1 joule of energy
absorbed per kg of mass
– 1 Gray = 100 rads
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Roentgen Equivalent Man
(Rem)
 This is the dose equivalent
 Expresses the biological impact of the
radiation exposure
 SI unit = Sievert
 1 Sievert = 100 rems
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Everyday Exposure
 Natural
– Cosmic rays (altitude, sunlight, plane
flights)
– Natural, ingested or inhaled terrestrial radio
nuclides
 Man Made
– Medical, nuclear storage facilities
– Products (lanterns, fire detectors)
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Maximum Permissible Dose
 Is set by the International Commission
on Radiological Protection for
occupationally exposed workers and the
public
 ALARA is 10% of MPD
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Occupationally Exposed
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Over 18
Possible to get 25% of MPD
Accept some risk
Limits set for various areas
– Eyes
– Hands
– Whole body
www.upei.ca/~vetrad
Pregnancy
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Must declare they are pregnant
Monitoring devices
Apron
First trimester most important
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Personnel Monitoring Devices
(PMD)
 Anyone who is likely to receive 25% or
more of the MPD should be monitored.
 Film Badges
 Pocket Dosimeter
 Thermoluminescent Dosimeter
– Know how they work, advantages and
disadvantages of each type
www.upei.ca/~vetrad
www.upei.ca/~vetrad
Radiation Damage
 DNA - sensitivity
 Somatic and genetic
 Early and Late
– Cancers
– cataracts
 Cumulative
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Time
 Exposure time should be kept as short
as possible
– Use a technique chart
 Screens
 Do not be in room unless necessary
www.upei.ca/~vetrad
Distance
 Again do not be in room unless
necessary
 Inverse square law
 Exposure switch outside room
 Cassette holder
 Wooden devices
www.upei.ca/~vetrad
www.upei.ca/~vetrad
www.upei.ca/~vetrad
Shielding
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Lead aprons
Lead gloves
Thyroid shield
Gonad shield
Lead glasses
Lead barriers, leaded glass, concrete
www.upei.ca/~vetrad
www.upei.ca/~vetrad
www.upei.ca/~vetrad
www.upei.ca/~vetrad
Restraint
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Tape
Gauze
Rope
Positioning trays
Foam wedges
Sandbags
drugs
www.upei.ca/~vetrad
www.upei.ca/~vetrad
www.upei.ca/~vetrad
www.upei.ca/~vetrad