Lecture 2: Radiation Safety Flashcards
X-rays are __, damage atoms by ejecting electrons
Ionizing
What is the result of Compton scatter
Electron is ejected and creates free radicals and affects DNA
What is the critical target in the body for radiation induced damage
DNA
Ionizing damage to DNA causes what 4 things
- Increase mutation rate
- Fetal abnormalities/ death
- Shortened life span
- Increase cancer risk
What radiation is the major source of exposure to veterinarians and technicians
Scatter radiation
Deterministic vs stochastic: which type of exposure has a threshold dose that exists and below that threshold side effects are not seen
Deterministic
With deterministic radiation exposure severity ___with dose
Increases
What are some side effect examples of deterministic radiation exposure
Radiation induced cataracts, radiation burns, sun burns
Deterministic vs stochastic radiation exposure: which can we prove and control
Deterministic
Stochastic radiation exposure severity is __of dose
Independent
T or F: no safe threshold exists for stochastic radiation exposure
True
What are some side effect examples of stochastic radiation exposure
Cancer, hereditary defects, mutations
T or F: we can prove stochastic side effects of radiation exposure
False
What are dosimeters used for
Measure radiation exposure
Where are dosimeters worn
- External badges at the level of the thyroid
- Badges under the gown at level of your belt
How often are dosimeters badges changed
Monthly or quarterly
What units are used to measure radiation exposure
Sv (Sieverts) and rem
1 Sv= __rem
100
What does Sieverts (Sv) and rem measure and take into account
Takes into account the amount of radiation energy deposited in tissues and also the types of radiation used
What is the occupational yearly dose limit for X-ray radiation exposure
0.05 Sv (5 rem)
What is the lifetime occupational dose limit for X-ray radiation exposure
Age in years (0.01 Sv) or 1rem
What is the dose limit for X-ray radiation exposure for pregnant people
0.05rem/month
What is ALARA
As low as reasonably achievable
How is ALARA achieved/what are the cardinal rules of radiation protection
- Decrease time
- Increase distance
- Shielding
What is passive restraint when performing X-rays
Sedate the patient, use restraints like sandbags and rope to reduce exposure
What is the inverse square law
Intensity of radiation at a given distance from a point source is inversely proportional to the square of the distance of the object from the source
Ex: if you move 4ft away from x-ray source, your exposure is reduced by __fold
16 fold (4^2)
What substances are used as shields placed between individuals and radiation source to reduce exposure
Lead and concrete
Body aprons, thyroid shields and gloves are made of ___most commonly
Lead impregnated vinyl
What two areas of human tissue are very radiation sensitive
Breast tissue and thyroid gland
Women or men: who is 4x more likely to develop radiation induced thyroid tumors
Women
Gowns and gloves are good at protecting form ___radiation not __
Scatter, not primary X-ray beam
How do you test your PPE equipment
X-ray gowns and gloves every 6 months to look for cracks
Why do you want to collimate primary X-rays to area of interest (2 reasons)
- Reduces scatter because less patient tissue is exposed to primary X-rays
- Improved image quality and decrease human exposure
What is the annual US average radiation exposure
360 mrem
How much radiation exposure occurs from a sunburn
200 rem
How much radiation exposure occurs from chest X-ray
25 mrem
