long wavelength
* Low frequency* Low energy* Less penetrating x-ray
Short wavelength
*High frequency, *High energy,*More penetrating x-ray
General/bremsstrahlung radiation
produced when high-speed electrons are stopped or slowed down by the tungsten atoms of the dental x-ray tube, an x-ray photon is created. more common
General radiation
EX: A & B.
Characteristic radiation
EX: C. created when an incoming electron interacts with the K-shell electron and knocks it out of orbit. When the electron void is filled with an outer shell electron, an x-ray photon is created. Must be at or above 70KV
Primary radiation
useful beam
Secondary radiation
X-radiation that is created when the primary beam interacts with matter
Scatter radiation
A form of secondary radiation that occurs when an x-ray beam has been deflected from its path by interaction with matter
Absorption
Transferring the energy of the x-rays to the atoms of the material through which the x-ray beam passes
Basic method of absorption
Ionization
When a beam of x-rays pass through matter, four possibilities exist-
*No interaction* Coherent scattering*Photoelectric effect* Compton effect
Coherent scattering
The incoming photon interacts with the atom, causing it to become excited. Electron vibrates. The x-ray does not lose energy but changes direction. New unmodified
photoelectric effect
High speed electron (called a photoelectron) knocks other electrons from the inner orbit creating an ion pair.
Compton scattering
Interaction with matter in which a higher energy photon strikes a loosely bound outer electron, removing it from its shell, and the remaining energy is released as a scattered photon. Most common, 60% of interactions with matter
Do x-rays make material they pass through radioactive?
No
SI Units of Radiation: (3)
Couloms/kilogram (C/kg)gray (Gy)sievert (Sv)
Exposure measurement
Measurement of ionization in air produced X-rays (Coulombs)
Absorbed dose measurement
How much was deposited (Gray)
Dose equivalent measurement
compares biologic effects of different kinds of radiation (Sieverts)
Effective dose equivalent
Aids in making more accurate comparisons between different radiographic exposures. Based on size and amount. Exposure on arm vs whole body
Electron shells are also called _______________.
energy levels
_______________ are bundles of energy that travel through space at the speed of light.
Photons
All electromagnetic radiation travels at a speed of _______________.
light
Dense structures, such as bone and enamel, will appear _______________ on a radiograph.
Radiopaque
____________________ accounts for only a very small portion of the x-rays produced in a dental x-ray machine.
Characteristic radiation
Energy is produced whenever the state of matter is naturally or artificially altered.
True
Atoms have the unique ability to retain their properties once they are split.
False
Wavelength and frequency are inversely related.
True
Frequency is the measure of the distance between two points on the electromagnetic spectrum.
False
The longer the wavelength, the more penetrating the radiation.
False
Soft x-rays are the result of long wavelengths and low frequencies.
True
Less dense structures, such as the pulp chamber of the tooth, will appear dark gray or black on a radiograph.
True
The Compton effect causes x-rays to be scattered in all directions.
True
X-rays cause radioactivity when they pass through structures.
False
Exposure to radiation does not produce a measurable dose until the radiation is absorbed in the tissues.
True
A unit of measurement that describes wavelengths of certain high-frequency radiation.
Angstrom
A process through which radiation imparts some or all of its energy to any material through which it passes.
Absorption
A common form of particulate (corpuscular) radiation.
alpha Particle
The smallest particle of an element that still has the properties of that element.
Atom
Long wavelengths of x-rays.
Soft radiation
What initiates X-rays exposure
Exposure button
To decrease magnification
Increase target receptor distance