X-ray Safety Flashcards
How does a low energy x-ray photon interact with an atom?
It causes the outer shell electron to vibrate. Then the electron returns to its stable state after releasing the photon’s energy as heat or light
How does a High Energy x-ray photon interact with an atom?
It ejects an electron creating an ion and a free electron called an ion pair.
If a photon has enough energy to knock out an atomic electron, what is it called?
Ionizing radiation
What happens if an atom that is ionized by a photon is part of a large molecule?
It can destroy the molecule’s ability to complete its cellular function
Why is it dangerous to ionize water?
Free radicals can result
How is Hydrogen peroxide created by water ionization?
two OH free rads combine
How is Hydroperozyl created by water ionization?
When an H radical combines with an O2 molecule
What is Direct Effect ionizing radiation
Energy of ionization that is directly imparted to critical chemicals like DNA, RNA, Enzymes, etc.
What is indirect effect ionizing radiation
When the radiation causes problems like water ionization that injure the cell via free radicals
What is the time between the exposure and the observed effect of the radiation called
latent period
Why are Alpha particles more damaging than x-rays or gamma rays?
They have a higher LET or linear energy transfer which means they unload all or their energy in a small space
What is the quality dose factor for neutrons
5
Radium and Thorium create what type of ionizing radiation?
Alpha particles
What is the quality dose factor for alpha particles?
20
What is the quality dose factor for xrays
1
If tissues divide quickly, are they more or less susceptible to radiation?
More
What two tissues are the least susceptible?
Nerve and Muscle
Why don’t you want to hold a drifting tube head?
Radiation burns and skin cancers
What is the threshold for CNS Syndrome
50+ grays
How long will CNS system patients live?
3 days, swelling in brain and spinal cord
What is the second most serious Total Body Irriadiation syndrom
GI Syndrome
10-50 grays
No survivors
What is the third most serious total body irradiation syndrome
Bone Marrow
2-10 grays
What is the greatest source of exposure to Americans
Radon in the earth’s crust. 54% of our annual exposure
Does exposure = dose?
No. Exposure is the amount coming out of the machine.
Dose is the amount absorbed by patient tissues
What is the maximum permissible dose for the dental team
50 mSv
What are the 3 tissues effected the most
Bone marrow
How can you reduce scatter
Use aluminum filtration
How thick should the aluminum filtration be?
2.5 mm
What does the aluminum filtration do?
Filters out low energy photons that will cause fog
What is collimation
Restricting the size and cross-sectional area of the beam
What is the max size of a round cone beam?
7 cm by law
What is the better shape for the beam?
Rectangular
Do you want a long cone or a short cone
Long, it reduces beam divergence more an more accurate beam
How often do x ray machines get checked in virginia?
Once every three years
what is the safe distance from the cone
6 feet
What product should you use for surface disinfection
quarternary disinfectant
How long do quarternary disinfectants last once diluted
28 days
What is the surface difinfection technique
spray….wipe…..spray
