RAD 100 - Ch 8 Radiographic & Fluoroscopic Equipment - Key Terms

Autotracking:

A feature of modern x-ray systems that enables simultaneous vertical movement of an upright image receptor and overhead x-ray tube.

Anode:

Positive electrode of the x-ray tube.

Bucky Mechanism:

Grid that is an integral part of the x-ray table, located below the tabletop and above a cassette receptor tray. It decreases the amount of scatter radiation reaching the image receptor, which improves image quality increases contrast. It also moves during exposure so that no grid lines appear on the image.

Cassette:

Lightproof holder for the image receptor. In computed radiography, the cassette holds the reusable photostimulable phosphor imaging plate; in conventional film-screen radiography, the cassette contains intensifying screens and a sheet of film.

Cathode:

Negative electrode of the x-ray tube.

Collimator:

Diaphragm or system of diaphragms made of an absorbing material; designed to define the dimensions and direction of a beam of radiation. This device consists of four rectilinear radiopaque blades that are adjustable to control the x-ray's field size and shape.

Digital Imaging:

Acquisition of static images in an electronic fashion; conversion of images to a digital format for image manipulation, enhancement, storage, and networking.

Diode:

Electrical component that possesses polarity with a negative and positive terminal.

DR Panel:

Common term for a flat-panel digital image receptor using either indirect or direct digital capture technology.

Flat-Panel Detector:

Type of digital detector employing amorphous silicon or selenium material bonded with thin-film transistor technology for digital image creation and amplification.

Fluoroscope:

Device used for dynamic radiographic examinations; usually consists of an x-ray tube situated underneath the x-ray table and an electronic image detector situated over the x-ray table.

Fluoroscopy:

Examination by means of the fluoroscope, employing image intensification.

Goniometer:

Angulation scale incorporated into the x-ray tube-head assembly to indicate the degree of x-ray tube angle relative to the image receptor.

Hard Copy:

Radiographic image created on a polyester film medium.

Latent Image:

Invisible image created after x-ray exposure and before image processing.

Longitudinal:

Lengthwise, or along the long axis.

Orthogonal:

A perpendicular relationship between the x-ray beam central ray (CR) and image receptor.

Overhead Tube Crane:

Mechanical support for suspending the x-ray tube and collimator assembly from the ceiling of the radiography room.

Picture Archival and Communication System (PACS):

Computer network for the transmission, viewing, and archival storage of medical images; often integrated into a larger hospital information system (HIS) and radiology information system (RIS).

Positive Beam Limitation (PBL):

Form of x-ray beam collimation of field size ensuring that the x-ray exposure field is no larger than the receptor size.

Postprocessing:

Manipulation of medical images after they have been acquired through x-ray exposure in order to improve image quality and diagnostic yield.

Pyrex Glass:

Special type of glass that can withstand very high temperatures from the x-ray tube anode.

Primary Barrier:

A receptor of x-radiation that intercepts the primary beam and prevents exposure if not interlocked with the central ray of the x-ray beam. In fluoroscopy, the fluoroscopic digital panel or image intensifier tube are primary barriers.

Radiolucent:

Describes a material that easily transmits x-ray energy with very little absorption.

Real-Time Images:

Images in which dynamic patient motion is visualized instantly as fluoroscopic imaging is occurring.

Remnant Radiation:

All radiation exiting the patient during exposure and ultimately striking the receptor.

Soft Copy:

Visualization of x-ray images using a video monitor for display and interpretation.

Spot Film:

Equipment that permits the acquisition of static images during a dynamic fluoroscopic examination; images are recorded using film or are acquired digitally and stored electronically.

Tether:

Electrical wire connection between a digital detector and the x-ray generator and computer.

Transverse:

Placed crosswise; situated at right angles to the long axis of a part.

Trendelenburg Tilt:

Table tilt angle in which the patient's head and thorax are lower than his or her legs.

Tube Angulation:

Pivoting the tube at the point where it is attached to its support.

Vertical:

Perpendicular to the plane of the horizon.

X-Ray Tube:

Device that produces x-rays.

X-Ray Tube Head:

Equipment consisting of the x-ray tube, collimator, and operator controls; permits manipulation of the x-ray tube in many directions for proper positioning.