Radiation Safety - University of Prince Edward Island
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Transcript Radiation Safety - University of Prince Edward Island
Radiation Safety
Dr. LeeAnn Pack
Diplomate ACVR
www.upei.ca/~vetrad
www.upei.ca/~vetrad
Radiation Safety
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
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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
Over 18
Possible to get 25% of MPD
Accept some risk
Limits set for various areas
– Eyes
– Hands
– Whole body
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Pregnancy
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
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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
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Distance
Again do not be in room unless
necessary
Inverse square law
Exposure switch outside room
Cassette holder
Wooden devices
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www.upei.ca/~vetrad
www.upei.ca/~vetrad
Shielding
Lead aprons
Lead gloves
Thyroid shield
Gonad shield
Lead glasses
Lead barriers, leaded glass, concrete
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www.upei.ca/~vetrad
www.upei.ca/~vetrad
Restraint
Tape
Gauze
Rope
Positioning trays
Foam wedges
Sandbags
drugs
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www.upei.ca/~vetrad
www.upei.ca/~vetrad
www.upei.ca/~vetrad