Radiology Chapters 38-42

Angulation

Alignment of central ray of x-ray beam in horizontal and vertical planes

ALARA Concept

As low as reasonably achievable

Ampere

A unit of electric current

Anode

Positive electrode in the x-ray tube

Artifact

Blemish or unintended radiographic image that is not present in the actual structure

Atom

Basic unit of matter

Automatic processor

Machine that automates all film-processing steps

Beam alignment device

Assists in the positioning of the position indicator device

Bitewing

Image view that shows the crowns of both arches on one film

Bisecting (bisecting of the angle) technique

Intraoral technique of exposing dental images

Bitewing

Type of image used for interproximal examination

Bremsstrahlung radiation

“braking radiation”; the sudden deceleration of electrons as they interact with highly positively changed nuclei

Calcium tungstate

Common type of phosphor

Cathode

Negative electrode in the x-ray tube

Cassette

Contains extraoral films during exposure

Central ray

X-rays at the center of the beam

Cephalometric film

Shows the bony and soft tissue areas of the facial profile

Cephalostat

Special device that allows the operator to easily position both film and patient

Charged coupled-device (CCD)

Solid-state image sensor used in intraoral digital imaging

Computer tomography (CT)

Radiographic technique the produces images or “slices” of one layer or section of the specific area; also referred to as computed axial tomography

Cone beam computed tomography (CBCT)

Three-dimensional digital imaging method that uses a cone-shaped beam of radiation that rotates around the patient

Confidentiality

Never revealing any personal information about the patient

Contact area

Area of the mesial or distal surfaces of a tooth that touches an adjacent tooth in the same arch

Contrast

Differences in degrees of blackness on an image

Control panel

Portion of the x-ray unit that contains the master switch, the indicator light, the selector buttons, and the exposure button

Crestal bone

Coronal portion of alveolar bone found between the teeth

Density

Overall darkness or blackness of an image

Dental radiography

Process of recording images of the teeth and adjacent structures to x-radiation

Developmental disability

Impairment of mental or physical functioning that usually occurs before adulthood and lasts indefinitely

Diagnostic quality

Referring to images with the proper structures and necessary density, contrast, definition, and detail for diagnostic purposes

Digital image

Electronic signals captured by sensors and displayed on computer monitors

Digital imaging

Filmless method of capturing an image and displaying it by using an image receptor, an electronic signal, and a computer to process and store the image

Digital panoramic units

Filmless method of recording a panoramic image and displaying it by using an electronic sensor and a computer to process and store the image

Digitize

Scanning of tradition film-based radiographs into a digital image

Disclosure

Process of informing the patient about a procedure, for example, the procedure of taking x-rays

Distortion

The disproportionate charge in the size of images that is caused by excessive or insufficient vertical angulation

Dosimeter

Used to measure the amount of occupational exposure to ionizing radiation

Duplicating film

Film designed for use in a film duplicating machines

Emulsion

Coating on the x-ray film that contains energy-sensitive crystals

Extraoral film

Film designed for use in cassettes

Extraoral images

Images taken when large areas of the skull or jaw must be examined

Extraoral imaging

Image of the tooth and bones made by placing the film or cassette against the face or the head and projecting the x-rays from the opposite side

Film composition

Fast film speeds result in less sharp detail because of the large crystal size

Film speed

Sensitivity of the emulsion on the film to radiation

Field of view

Area that can be shown when performing imaging procedures

Focal trough (trof)

Imaginary three-dimensional horseshoe-shaped zone used to focus panoramic radiographs

Focal spot size

A machine with a small focal spot produces a sharper image than a machine with a larger focal spot size

Frankfort plane

Imaginary plane that passes through the top of the ear canal and the bottom of the eye socket

Image Receptor

A recording medium; examples include x-ray film, phosphor plate, or digital sensor

Informed consent

Permission granted by a patient after being informed about the risks, benefits, and alternatives of a procedure

Intensifying screen

Part inside an extraoral cassette that converts x-ray energy into visible light, which in turn exposes screen film

Interproximal

Between two adjacent surfaces

Intersecting

Cutting across or through

Intraoral film

Film designed for placement in the patient’s mouth

Ionization radiation

Harmful and produces biologic changes on living tissues

Kilovoltage

Highest voltage of x-ray tube used during an exposure

Label side

Colored side of the film that faces the tongue

Latent

Time between exposure to ionizing radiation and appearance of symptoms

Latent image

invisible image on the x-ray film after exposure but before processing

Lead apron

Device used to protect the reproductive and blood-forming tissues from scatter radiation

Liability

Accountability or legal responsibility

Long axis of the tooth

Imaginary line dividing the tooth longitudinally(vertically) into two equal halves

Magnification

Proportional enlargement of an image

Malpractice

Professional negligence

Matter

Anything that occupies space and has form or shape

Midsagittal plane

Imaginary line that divides the patient’s face into right and left side

Milliampere (MA)

One one-thousandth (1/1000) of an ampere; a unit of measurement used to describe the intensity of an electrical current

Movement

Any movement of the patient or image receptor (the film or sensor), no matter how slight, will degrade the sharpness of the image

Negligence

Failure to provide a proper or reasonable level of care

Occlusal

Radiographic view that shows larger areas of the maxilla or mandible

Occlusal technique

Used to examine large areas of the upper or lower jaw

Panoramic film

Used in cassettes to provide a wide-view of both the upper and lower jaws

Parallel

Moving or lying in the same plane, always separated by the same distance

Paralleling technique

Intraoral technique of exposing periapical and bitewing images

Penumbra

Blurred or indistinct area that surrounds an image

Periapical

Radiographic view that shows the crown, root tip, and surrounding structures

Perpendicular

Intersescting at or forming a right angle

Personal radiation monitoring badge

Device that measures exposure of personnel to ionizing radiation by measuring the intensity of visible light emitted from a crystal in the detector when heated; the intensity of light emitted depends on the radiation exposure

Photon

Minute (tiny) bundle of pure energy that has no weight or mass

Phosphor storage plate (PSP)

Reusable film-sized plated coated with phosphor as the image receptor

Physical disability

Impairment in certain function(s) of the body, such as vision, hearing, or mobility

Positioning instruments (device)

intraoral devices used to position and hold the film, sensor, or PSP

Primary beam

Most penetrating beam produced at the target of the anode

Primary radiation

Is made up of x-rays that come from the target of the x-ray tube. Primary radiation is often referred to as the useful beam , or primary beam

Quality (of x-ray beam)

Mean energy or penetrating ability of the x-ray beam

Quality assurance

Plan to ensure that the dental office produces consistent, high-quality images with a minimum of exposure to patients and personnel

Quality control tests

Specific tests used to ensure quality in dental x-ray equipment, supplies, and film processing

Quantity (of x-ray beam)

Number of x-rays produced in the dental unit; the quantity of x-rays produced is controlled by mA

Radiation

Forms of waves of energy emission through space or material

Radiograph

Image produced on photosensitive film by exposing the film to radiation and then processing it

Radiology

The science of study of radiation as used in medicine; a branch of medical science that deals with the therapeutic use of x-rays, radioactive substances, and other forms of radiant energy

Right angle

Angle of 90 degrees formed by two lines perpendicular to each other

Risk management

Policies and procedures that will reduce the chance that a malpractice lawsuit will be brought against the dentist; key areas of risk management include patient informed consent, patient records, confidentiality, liability issues, and patient education

Scatter radiation

Form of secondary radiation that occurs when an x-ray beam has been deflected from its path by interaction with matter

Secondary radiation

X-radiation that is created when the primary beam interacts with matter

Sensor

Solid-state image receptor that contains a silicon chip with an electric circuit

Sharpness

Measure of how well an image reproduces the fine details or outline of an object

Somatic effects

Effects of radiation that cause illness and are responsible for poor health (such as cancer, leukemia, and cataracts) but are not passed on to offspring

Standard of care

Level of knowledge, skill, and care comparable with that of other dentists who are treating similar patients under similar conditions

Stepwedge

Device constructed of layered aluminum steps to demonstrate film densities and contrasts