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