Chapters 1-2: Radiation History & Radiation Physics Flashcards
Ionization, X-Radiation, X-ray Machine, Dental X-ray Production
List the two types of electrical circuits used in the production of x-rays.
- filament circuit / low-voltage circuit
- high-voltage circuit
Define the term: photoelectric effect
- one of the interactions of x-radiation with matter in which the x-ray photon collides with a tightly-bound, inner-shell electron and gives up all its energy to eject the electron from its orbit
- all of the energy of the photon is absorbed by the displaced electron in the form of kinetic energy
What component of the tubehead surrounds and protects the x-ray tube with insulating oil?
the metal housing
Define the term: ion
- an electrically unbalanced particle
- an atom that gains or loses an electron
How is voltage measured in the production of x-rays?
kilovoltage (kVp)
What is the term for the electrical current when the electrons flow in one steady, constant direction through the conductor?
direct current (DC)
Define the term: image
a picture or likeness of an object
What component of the anode in the x-ray tube us used to dissipate the heat away from the tungsten target during the production of x-ray photons?
the copper stem
List the two parts of an atom
- nucleus
- electrons in orbit
Which type of x-radiation is the most detrimental to humans?
scatter radiation
Describe the process of the electrical current in a step-down transformer.
- the primary/input coil contains more wire coils that receive and energize the alternating electrical current
- this induces an electrical current in the secondary/output coil that contains less wire coils
- the resulting electrical current is directed in the x-ray tube
Define the term: x-ray
a beam of energy that has the power to penetrate substances and record image shadows on image receptors
What is the particle concept of electromagnetic radiations?
electromagnetic radiations are discrete bundles of energy with no mass or weight that travel in waves at the speed of light in a straight line
Why would a substance be considered radioactive?
if it gives off energy in the form of particles or rays as a result of the disintegration of the atomic nuclei
What charges are present in a neutral atom?
an equal number of protons (positive charges) and electrons (negative charges)
What is the term for the path of an electrical current?
circuit
What percentage of Compton scatter occurs in dental radiography?
62%
How many volts are used in the high-voltage circuit?
65,000-100,000 V
How many volts are used in the filament circuit?
3-5 V
What is considered “the heart” of the x-ray generating system?
the x-ray tube
What forms when atoms are combined?
molecules
What is the wave concept of electromagnetic radiation?
electromagnetic radiations are waves that travel in various wavelengths at the speed of light
Which component of the cathode in the x-ray tube produces electrons when heated?
tungsten filament
Is the cathode in the x-ray tube positively or negatively charged?
negatively charged
What is radiography the science of?
the art and science of making radiographs by the exposure of an image receptor to x-rays
Describe the speed of x-rays.
X-rays travel at the speed of light
Define the term: dental radiograph
a photographic image produced on an image receptor by the passage of x-rays through teeth and related structures
What is the term used to measure the speed of a wave?
velocity
Define the term: element
substances made up of only one type of atom
Are frequency and wavelength conversely or inversely related?
conversely (if the frequency of the wave is high, the wavelength will be short, and vice versa)
How is the atomic number of an atom determined?
by the number of protons inside the nucleus, which equals the number of electrons outside the nucleus
List the four types of particulate radiation.
- electrons (beta particles or cathode rays)
- alpha particles
- protons
- neutrons
Define the term: beta particles
fast-moving electrons emitted from the nucleus of radioactive atoms
What is the conversion of alternating to direct current of electricity?
rectificatoin
What are placed in the in the x-ray tubehead to filter out the nonpenetrating, longer-wavelength x-rays from the exiting x-ray beam?
aluminum disks
What is the purpose of a step-up transformer?
to increase the voltage from the incoming 110-220 line voltage to the necessary 65,000-100,000 V used by the high-voltage circuit
Define the term: nucleus
the dense core of the atom, composed of protons and neutrons
How do electrons travel inside an atom?
in well-defined paths called orbits or shells
What is the purpose of an autotransformer?
a voltage compensator that automatically corrects minor fluctuations in the electrical current
Define the term: dental imaging
the creation of digital, print, or film representations of anatomic structures for the purpose of diagnosis
Describe the fluorescence capabilities of x-rays.
X-rays can cause certain substances to fluoresce or emit radiation in longer wavelengths
List the two concepts of that describe how electromagnetic radiations move through space.
- particle concept
- wave concept
What electrical charge do neutrons carry?
- no electrical charge
- they are neutral
Approximately how much of the x-ray energy produced at the anode is considered general radiation?
approximately 70%
What component of the anode in the x-ray tube serves as a focal spot for the bombarding electrons from the cathode, which will then convert those electrons into x-ray photons?
the tungsten target
Define the term: scatter radiation
a form of secondary radiation that is caused by an x-ray beam being deflected from its path by its interaction with matter
List the two components of the anode in the x-ray tube.
- tungsten target
- copper stem
What component of the x-ray tubehead aims and shapes the exiting x-ray beam?
the position-indicating device (PID)
Define the term: secondary radiation
x-radiation that is created when the primary beam interacts with matter
Describe the penetrating power of x-rays.
X-rays can penetrate liquids, solids, and gases, depending on the composition of that substance
What occurs when matter is altered?
energy
Where is the beginning of the electricity needed to generate x-rays created?
when the x-ray machine is turned on, the electrical current enters the control panel from the wall outlet
How are electromagnetic radiations arranged?
according to their energies on the electromagnetic spectrum
Define the term: coherent scatter / unmodified scatter
- one of the interactions of x-radiation with matter in which the path of a low-energy x-ray photon interacts with an outershell electron
- no change in the atom occurs
- scatter radiation is produced
What occurs when the x-rays produced inside the tube are directed to exit the tubehead?
- the leaded-glass housing prevents the x-rays from escaping in all directions and allows a small number to pass through
- the x-rays travel travel through th tubehead seal and the aluminum disks filter out the longer wavelengths from the x-ray beam
- the lead collimator restricts the size of the x-ray beam
- the remaining x-ray beam travels down the position-indicating device and exit at the opening of the tubehead
What component of the x-ray tubehead alters the voltage of the incoming electricity?
the transformer
What component of the x-ray tubehead seals in the insulating oil and filters out the x-ray beam?
the tubehead seal
Describe the appearance of x-rays.
X-rays are invisible