Www.upei.ca/~vetrad Radiation Safety Dr. LeeAnn Pack Diplomate ACVR.
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Transcript of Www.upei.ca/~vetrad Radiation Safety Dr. LeeAnn Pack Diplomate ACVR.
Radiation Safety
Dr. LeeAnn Pack
Diplomate ACVR
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
ALARA
National Council on Radiation Protection– Publishes recommendations for radiation
limits Most groups follow their guidelines
As Low As Reasonably Achievable
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.
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
Roentgen Equivalent Man (Rem)
This is the dose equivalent Expresses the biological impact of the
radiation exposure SI unit = Sievert 1 Sievert = 100 rems
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)
Maximum Permissible Dose
Is set by the International Commission on Radiological Protection for occupationally exposed workers and the public
ALARA is 10% of MPD
Occupationally Exposed
Over 18 Possible to get 25% of MPD Accept some risk Limits set for various areas
– Eyes– Hands– Whole body
Pregnancy
Must declare they are pregnant Monitoring devices Apron First trimester most important
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
Radiation Damage
DNA - sensitivity Somatic and genetic Early and Late
– Cancers– cataracts
Cumulative
Time
Exposure time should be kept as short as possible– Use a technique chart
Screens Do not be in room unless necessary
Distance
Again do not be in room unless necessary
Inverse square law Exposure switch outside room Cassette holder Wooden devices
Shielding
Lead aprons Lead gloves Thyroid shield Gonad shield Lead glasses Lead barriers, leaded glass, concrete
Restraint
Tape Gauze Rope Positioning trays Foam wedges Sandbags drugs