Introduction

Question 1

Define Energy

Answer 1

-The ability to do work

Question 2

What are examples of electromagnetic energy (EME)?

Answer 2

• X-rays
• radiowaves
• microwaves
• UV rays
• Infrared rays
• Visible light

Question 3

How do you create EME?

Answer 3

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

Question 4

What is radiation?

Answer 4

-the energy in transit

Question 5

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

Answer 5

-irradiated/exposed

Question 6

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

Answer 6

• ionization

- X-Rays, Gamma rays, UV light

Question 7

What is the relationship between EME and wavelength?

Answer 7

• EME is inversely proportional to wavelength

- EX: short wavelength/high frequency = greater energy

Question 8

What are the 2 sources of ionizing radiation?

Answer 8

• Cosmic

- Man-made

Question 9

What are cosmic rays (give example)?

What is terrestrial radiation produced by?

Answer 9

• particulate radiation (Sun and Stars)

- uranium, thorium, and other nuclides

Question 10

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

Answer 10

• Radon Gas

- all earth-based materials (concrete and brick)

Question 11

What is the largest source of man-made energy?

Answer 11

-Medical imaging

Question 12

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

Answer 12

-Wilhelm Roentgen

Question 13

What are the properties of X-rays?

Answer 13

• 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

Question 14

How are X-rays produced?

Answer 14

-When electrons from cathode slam into the anode

Question 15

What is part of the imaging system?

Answer 15

• X-ray tube
• Operating console
• High-voltage generator

Question 16

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

Answer 16

-isotropically (in all directions)

Question 17

What is a cathode? What is it composed of?

Answer 17

• negative charged end of the X-ray tube

- heat resistant filament made of thoriated tungsten

Question 18

Explain thermionic emission

Answer 18

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

Question 19

Explain space-charge effect

Answer 19

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

Question 20

What is Dual-Focus?

Answer 20

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

Question 21

What is needed when imaging a large body part?

Answer 21

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

Question 22

What is an anode and its 3 functions?

Answer 22

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

Question 23

What is the Line-Focus principle?

Answer 23

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

Question 24

What is the anode-heel effect?

Answer 24

-the anode side must always face the thinner body part

Question 25

What is off-focus radiation?

Answer 25

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

Question 26

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)?

Answer 26

X-ray generator and transformer

Question 27

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

Answer 27

Control Panel

Question 28

What is a step-up transformer?

Answer 28

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

Question 29

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

Answer 29

Rectification

Question 30

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

Answer 30

Collimator

Question 31

What is added filtration’s role?

Answer 31

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

Question 32

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

Answer 32

• mA station
• kV selection
• time in seconds

Question 33

What is the Bucky system?

Answer 33

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

Question 34

What is radiographic film composed of and coated with?

Answer 34

• composed of: polyester

- coated with: Silver Halide Crystals (SHC)

Question 35

What value is responsible for X-ray quantity?

Answer 35

mAs

Question 36

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

Answer 36

kilovoltage peak (kVp)

Question 37

What value is responsible for X-ray quality?

Answer 37

kVp

Question 38

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

Answer 38

kVp: 4% change
mAs: 30% change

Question 39

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

Answer 39

10-15 kVp

Question 40

What equations will give 50 mAs?

Answer 40

100 mA x 0.5 sec

200 mA x 0.25 sec

Question 41

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

Answer 41

radiation dose reduction

Question 42

What is the 10 kVp rule?

Answer 42

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