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D2: 621 Radiology > X-ray Safety > Flashcards

Flashcards in X-ray Safety Deck (38)
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1

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

2

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.

3

If a photon has enough energy to knock out an atomic electron, what is it called?

Ionizing radiation

4

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

5

Why is it dangerous to ionize water?

Free radicals can result

6

How is Hydrogen peroxide created by water ionization?

two OH free rads combine

7

How is Hydroperozyl created by water ionization?

When an H radical combines with an O2 molecule

8

What is Direct Effect ionizing radiation

Energy of ionization that is directly imparted to critical chemicals like DNA, RNA, Enzymes, etc.

9

What is indirect effect ionizing radiation

When the radiation causes problems like water ionization that injure the cell via free radicals

10

What is the time between the exposure and the observed effect of the radiation called

latent period

11

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

12

What is the quality dose factor for neutrons

5

13

Radium and Thorium create what type of ionizing radiation?

Alpha particles

14

What is the quality dose factor for alpha particles?

20

15

What is the quality dose factor for xrays

1

16

If tissues divide quickly, are they more or less susceptible to radiation?

More

17

What two tissues are the least susceptible?

Nerve and Muscle

18

Why don't you want to hold a drifting tube head?

Radiation burns and skin cancers

19

What is the threshold for CNS Syndrome

50+ grays

20

How long will CNS system patients live?

3 days, swelling in brain and spinal cord

21

What is the second most serious Total Body Irriadiation syndrom

GI Syndrome

10-50 grays

No survivors

22

What is the third most serious total body irradiation syndrome

Bone Marrow

2-10 grays

23

What is the greatest source of exposure to Americans

Radon in the earth's crust. 54% of our annual exposure

24

Does exposure = dose?

No. Exposure is the amount coming out of the machine.

Dose is the amount absorbed by patient tissues

25

What is the maximum permissible dose for the dental team

50 mSv

26

What are the 3 tissues effected the most

Bone marrow

27

How can you reduce scatter

Use aluminum filtration

28

How thick should the aluminum filtration be?

2.5 mm

29

What does the aluminum filtration do?

Filters out low energy photons that will cause fog

30

What is collimation

Restricting the size and cross-sectional area of the beam