Radiation Safety

Types of radiation damage to cells

Reparable - repaired without incident

Reparable with errors - increased risk of cancer, risk of birth defeces

Irreparable - high doses of radiation can kill cells, leading to tissue damage (Ex: cataracts to lens of eyes)

What is the unit absorbed dose equivalent used for radiation safety

Sievert (Sv)

1 Rem is equal to how many mSv

10 mSv (basically 10x or just add the 0)

Maximum permissible dose limit for whole body

50 mSv (5 rem)

Maximum permissible dose limit for skin extremities

500 mSv (50 rem)

Maximum permissible dose limit for eye or lens dose

150 mSv (15 rem)

Maximum permissible dose limit for pregnant women

5 mSv or 0.05 mSv in any month

When taking radiographs as a pregnant women, what is the most important period of time to worry about the embryo

First 3 months - the embryo is most sensitive to adverse radiation effects at this time

Maximum permissible dose limit for young people under 18 years

They should be excluded from performing or assisting in radiographic exams

Occupation dose limit for them is 10% of the limit for adults

Registered vet techs can operate under radiographic equipment under

Indirect supervision of a licensed veterinarian

What is the main guiding principle of radiation protection

ALARA - as low as reasonably achievable

What are the ways to minimize radiation exposure

Decrease time of exposure

Plan carefully and avoid retakes

Increase distance from radiation source

Increase shielding between individuals and radiation source

Use lead equipment and shielding

How do we decrease time of exposure to radiation

Use chemical or mechanical restraints when possible so individuals dont need to be in x-ray

Use rare-earth screens to decrease exposure

How do we increase our distance from radiation source and why

Make sure we stand away from the x-ray beam as far away as possible

B/c of the inverse squares law

What are ways to increase shedding between individuals and radiation source

Protective barriers

Individuals in an x-ray room should stand behind a protective barrier or wear a protective apron

How thick should a lead apron or gloves be to reduce a 100 kVp x-ray beam by 60%

0.25 mm

How thick should a lead apron or gloves be to reduce a 100 kVp x-ray beam by 85%

0.5 mm lead equivalent

What kind of radiation does shielding devices protect the wearer from

Scatter radiation only*

What are the common monitoring devices we use

Film badges

thermoluminescent dosimeters (TLDs)

Pocket dosimeters

ring or wrist badges

Where should or monitoring devices be worn

Should be worn at thyroid level on collar outside apron