Introduction Flashcards

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1
Q

Define Energy

A

-The ability to do work

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2
Q

What are examples of electromagnetic energy (EME)?

A
  • X-rays
  • radiowaves
  • microwaves
  • UV rays
  • Infrared rays
  • Visible light
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3
Q

How do you create EME?

A

-converting electrical energy to X-ray photons via the imaging system

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4
Q

What is radiation?

A

-the energy in transit

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5
Q

What is it when matter intercepts and absorbs radiation said to be?

A

-irradiated/exposed

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6
Q

What is radiation when an electron is removed from its orbital? What forms of EME are capable of this matter?

A
  • ionization

- X-Rays, Gamma rays, UV light

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7
Q

What is the relationship between EME and wavelength?

A
  • EME is inversely proportional to wavelength

- EX: short wavelength/high frequency = greater energy

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8
Q

What are the 2 sources of ionizing radiation?

A
  • Cosmic

- Man-made

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9
Q

What are cosmic rays (give example)?

What is terrestrial radiation produced by?

A
  • particulate radiation (Sun and Stars)

- uranium, thorium, and other nuclides

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10
Q

What is the largest source of natural energy? What materials contain it?

A
  • Radon Gas

- all earth-based materials (concrete and brick)

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11
Q

What is the largest source of man-made energy?

A

-Medical imaging

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12
Q

Who was the first man to recognize the significance of radiation and x-rays?

A

-Wilhelm Roentgen

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13
Q

What are the properties of X-rays?

A
  • No charge
  • Invisibility
  • Penetrability of most matters dependent on Z
  • Ionization and biological effect
  • Making compounds fluoresce and emit light
  • travel at the speed of light
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14
Q

How are X-rays produced?

A

-When electrons from cathode slam into the anode

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15
Q

What is part of the imaging system?

A
  • X-ray tube
  • Operating console
  • High-voltage generator
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16
Q

How are X-rays emitted in an X-ray tube?

A

-isotropically (in all directions)

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17
Q

What is a cathode? What is it composed of?

A
  • negative charged end of the X-ray tube

- heat resistant filament made of thoriated tungsten

18
Q

Explain thermionic emission

A

-When filament temperature is high enough for the electrons to ejected from the filament

19
Q

Explain space-charge effect

A

-When an electron cloud repels any additional electrons from being emitted from the filament

20
Q

What is Dual-Focus?

A

-2 focal spots on the anode corresponding to large and small filaments of the cathode

21
Q

What is needed when imaging a large body part?

A

-More than 400mA (large filament and large focal spot)

22
Q

What is an anode and its 3 functions?

A
  • Positive charged end of X-ray tube
    1) target of x-ray photons
    2) rotates and dissipates heat
    3) electrical conductor
23
Q

What is the Line-Focus principle?

A

-By angling the focal spot target (5-15 degrees), allows for a larger area of heat dissipation while maintaining a small focal spot

24
Q

What is the anode-heel effect?

A

-the anode side must always face the thinner body part

25
Q

What is off-focus radiation?

A

X-rays from other areas than the focal spot are being produced

26
Q

What modifies incoming voltage and current to provide an X-ray tube with the power needed to produce an X-ray beam of the desired kilo-voltage (kV), current (mA), and minimal duration (time)?

A

X-ray generator and transformer

27
Q

What permits selection of technical factors of initiation of radiographic exposures: mA, kV, time?

A

Control Panel

28
Q

What is a step-up transformer?

A

-Supplies high voltage to X-ray tube (voltage increases and current decreases)

29
Q

What converts alternating current (AC) to direct current (DC)?

A

Rectification

30
Q

What is used to reduce the patient’s dose by restricting the X-ray beam to the desired anatomy?

A

Collimator

31
Q

What is added filtration’s role?

A

-To harden the beam and remove lower energy X-rays

32
Q

What are the 3 components to the operator’s console?

A
  • mA station
  • kV selection
  • time in seconds
33
Q

What is the Bucky system?

A

-contains grid to remove scatter radiation and improve image quality.

34
Q

What is radiographic film composed of and coated with?

A
  • composed of: polyester

- coated with: Silver Halide Crystals (SHC)

35
Q

What value is responsible for X-ray quantity?

A

mAs

36
Q

What is known as the amount of energy that an X-ray beam possesses?

A

kilovoltage peak (kVp)

37
Q

What value is responsible for X-ray quality?

A

kVp

38
Q

How much of a percentage in kVp is needed to notice visible changes? mAs?

A

kVp: 4% change
mAs: 30% change

39
Q

How much of a change in kVp is equivalent to 50% change in mAs?

A

10-15 kVp

40
Q

What equations will give 50 mAs?

A

100 mA x 0.5 sec

200 mA x 0.25 sec

41
Q

What will reducing time of exposure result in with the patient?

A

radiation dose reduction

42
Q

What is the 10 kVp rule?

A

Changing the tube voltage by 10kVp will result in the same image density if you were to either increase or decrease mAs by 50%