DETH 103 Radiography

Dental Therapy

A field of dentistry that involves the prevention, diagnosis, and treatment of oral diseases and disorders.

Radiography Theory

The study of the principles and concepts of radiation and radiation safety in dental radiography.

Radiology

The science of radiation.

Radiography

The science of making a radiograph by exposing, processing, and creating an image.

Radiograph

The resulting picture from a radiographic image, which can be digital or film-based.

X-Rays

High-energy electromagnetic waves used in dentistry to produce images of teeth and surrounding structures.

Ionizing Radiation

Radiation that has enough energy to remove tightly bound electrons from atoms, causing ionization.

Electromagnetic Radiation

The propagation of wavelike energy (without mass) through space or matter, including visible light, radar, radio, and television waves.

Ionization

The process of converting an atom into ions by removing or adding electrons.

Dental X-Ray Machine

A device used to produce and capture dental radiographic images.

Control Panel

The part of the dental x-ray machine that contains switches, buttons, and controls for adjusting exposure settings.

Extension Arm

The part of the dental x-ray machine that suspends the x-ray tubehead and allows for movement and positioning.

Tubehead

The housing that contains the x-ray tube and other components necessary for producing x-rays.

X-Ray Tube

A glass vacuum tube that generates x-rays when electrons collide with a metal target.

Anode

The positive electrode in the x-ray tube that converts electrons into x-ray photons.

Cathode

The negative electrode in the x-ray tube that supplies the electrons necessary to generate x-rays.

Electricity

The energy used to make x-rays in a dental x-ray machine.

Electrical Current

The flow of electrons through a conductor, such as the cathode filament in a dental x-ray machine.

Milliamperage Adjustment

A control on the dental x-ray machine that can increase or decrease the number of electrons passing through the cathode filament.

Kilovoltage Peak (kVp) Adjustment

A control on the dental x-ray machine that can control the current passing from the cathode to the anode.

Transformers

A device used to either increase or decrease the voltage in an electrical circuit.

Step-Down Transformer

Used to decrease voltage from the incoming 110- or 220-line voltage to the 3 to 5 volts used by the filament circuit.

Step-Up Transformer

Used to increase incoming voltage to 65,000 to 100,000 volts used by the high-voltage circuit.

Autotransformer

A type of transformer used to adjust the electrical circuits.

Position Indicating Device (PID)

A device used in X-ray imaging to control the size and shape of the X-ray beam.

Collimator

A metallic barrier used to reduce the size and shape of the X-ray beam.

Aluminum Filter

Material placed in the X-ray beam to absorb lower energy photons.

Primary Beam

The main X-ray beam that is directed towards the patient's face and reacts with the image receptor area.

X-Rays

High-energy electromagnetic radiation produced when electrons strike a target material.

Tungsten Target

The target material in an X-ray tube that is struck by electrons to produce X-rays.

Primary Radiation

The penetrating X-ray beam produced at the target of the anode.

Secondary Radiation

X-radiation created when the primary beam interacts with matter.

Scatter Radiation

A form of secondary radiation that occurs when X-rays are deflected from their path by interaction with matter.

No Interaction

X-ray photons pass through the atom unchanged and leave the atom unchanged.

Absorption

The process by which X-ray photons transfer their energy to matter.

Photoelectric Effect

The absorption of X-ray photons by inner-shell electrons, resulting in the ejection of the electron and the production of an image.

Compton Scatter

The deflection of X-ray photons by outer-shell electrons, resulting in a change in direction and a decrease in energy.

X-ray Beam Quality

The mean energy or penetrating ability of the X-ray beam.

X-ray Beam Quantity

The number of X-ray photons produced in the dental X-ray unit.

Intensity

The product of the quantity and quality of X-ray photons per unit of area per unit of time of exposure.

Kilovoltage (kV)

The potential difference between two electrical charges.

Kilovoltage Peak (kVp)

The maximum or peak voltage of an alternating current.

Film Density

The overall darkness or blackness of a dental X-ray film.

Exposure Time

The interval of time during which X-rays are produced.

Milliamperage (mA)

The measure of the amount of electrons passing through the cathode filament.

Amperage (A)

The unit of measure used to describe the number of electrons or current flowing through the cathode filament.

Milliampere-Seconds (mAs)

The product of milliamperes and exposure time, used to control the density of the X-ray film.

X-ray Beam Intensity

The product of the quantity and quality of X-ray photons per unit of area per unit of time of exposure.

Milliamperage

Controls the penetrating power of the x-ray beam by controlling the number of electrons produced in the x-ray tube and the number of x-rays produced.

Exposure Time

Affects the number of x-rays produced. A longer exposure time produces more x-rays and a more intense x-ray beam.

Distance

The distance traveled by the x-ray beam affects the intensity of the beam. There are three types of distances:target-surface (source to patient's skin), target-object (source to patient's tooth), and target-film (source to film).

Divergence

As x-rays travel from their point of origin, they diverge and spread out to cover a larger surface area. The intensity of the beam lessens.

Inverse Square Law

"The intensity of radiation is inversely proportional to the square of the distance from the source of radiation." When the distance is doubled, the beam is one quarter as intense. When the distance is halved, the beam is four times more intense.