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Flashcards in Module 2 Deck (18)
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1
Q

An atom is a ______ with a ________ and _________ that are _______

A

Fundamental unit of matter
Central nucleus (positively charged)
Orbiting electrons
Negatively charged

2
Q

Describe ionization (production of ions)

A

Process of converting an atom (neutrally charged) into ions (electrically unbalanced) by loosing an electron

3
Q

Differentiate radiation from radioactivity

A

Radiation: formation of energy in the form of waves or particles

Radioactivity: a substance with unstable atoms or elements that undergo spontaneous disintegration or decay

4
Q

Describe x-radiation

A

Conversion of electric energy to radiation

5
Q

List the properties of x-radiation

A

Invisible
Consists of energy (photons)
Travels in lines at the speed of light
Moves in form of transverse (small) waves
Penetrates tissues/structures
Affects film emulsion producing latent image
Can affect/impact living tissue

6
Q

Review parts of the x-ray tube head and the x-ray tube

A

Tube head: Aluminum disks, lead collimator, PID, tube head seal, x-ray tube, insulating oil, unleaded glass window, and metal housing of x-ray tube head

X-ray tube: Tungsten filament, molybdenum cup, electron stream, tungsten target, copper stem, vacuum, x-ray beam, and lead-glass housing

7
Q

Describe the purpose of transformers

A

Transformers change the alternating current in the machine to decrease/increase the typical 110 volts that enter the machine when plugged into the wall

8
Q

Describe the step-down transformer

A

mA circuit is part of the step-down transformer
Decrease the wall outlet voltage from 110 volts to 3-5 volts in the filament circuit
When turned on the filament in the cathode (-) terminal heats up and produces an electron cloud

9
Q

Describe the step-up transformer

A

kVp circuit is part of the step-up transformer
Increases house voltage of 110 volts to 65,000-100,000 volts (65-100 kVp)
When exposure button is hit, the (-) electrons are attracted to the anode (+) and high speed electrons hit the tungsten target and then leave the tube

10
Q

Explain the process in which x-rays are produced within the x-ray tube

A

Machine is turned on
The tungsten filament in the cathode (-) forms and electron cloud
When the exposure button is activated the high voltage circuit is completed
Electrons are attracted across the tube head to the tungsten target on the anode (+)
X-rays are produced when the high speed electrons strike the tungsten target
X-rays are then directed out of the tube head because of the angled tungsten target so you can take an image on the film/sensor

11
Q

In the process of x-ray production, how much energy is converted into x-rays and how much is converted into heat?

A

1% x-rays

99% heat

12
Q

Explain Bremsstrahlung (general) and characteristic radiation

A

Bremsstrahlung: “braking radiation” high-speed electrons suddenly stop when they hit the tungsten target in the anode

Characteristic: produced when a high-speed electron dislodges an inner-shell electron from the tungsten atom and causes ionization of that atom

13
Q

Which type of radiation occurs most frequently within the dental x-ray tube?

A

Bremsstrahlung (70%)

14
Q

When does Characteristic radiation occur?

A

70 kVp or above

15
Q

Describe primary radiation

A

Penetrating x-ray beam that is produced at the target and exits the tube head; useful beam

16
Q

Describe secondary radiation

A

Created when the primary beam interacts with matter (skin, bones, teeth, etc); less penetrating than primary radiation

17
Q

Describe scatter radiation

A

Form of secondary radiation and is the result of x-rays that have been deflected by interaction with matter; usually absorbed by construction materials

18
Q

Describe the possible interactions of x-rays with matter

A

X-rays can pass through the pt without any interaction
X-ray photons can be completely absorbed by the pt
X-ray photons my be scattered