Ch. 7 & 8 Vocab. In Intro To Radiography

Front 1

Attenuation

Back 1

process by which a beam of radiation is reduced in energy when passing through tissue or other materials

Front 2

Central Ray

Back 2

theoretical center of a beam of radiation

Front 3

Contrast

Back 3

difference between adjacent densities on a radiograph

Front 4

Density

Back 4

degree of darkening of exposed and processed photographic or radiographic film

Front 5

Distortion

Back 5

misrepresentation of the true size or shape of an object

Front 6

Dynamic

Back 6

with motion

Front 7

Fog

Back 7

unwanted exposure or film densities

Front 8

Grid

Back 8

device consisting of thin lead strips designed to permit primary radiation to pass while reducing scatter radiation

Front 9

Half-Value Layer

Back 9

amount of filtration necessary to reduce the intensity of the radiation beam to one half its original value

Front 10

Image Receptor

Back 10

medium used to capture the image for recording, such as x-ray film or a digital imaging plate

Front 11

Intensifying Screen

Back 11

layer of luminescent crystals placed inside a cassette to expose x-ray film efficiently and thereby significantly reduce patient dose

Front 12

Inverse Square Law

Back 12

mathematical formula that describes the relationship between radiation intensity and distance from the source of the radiation

Front 13

Kilovoltage Peak (kVp)

Back 13

measure of the potential difference, which controls the quality and quantity of x-ray photons produced in the x-ray tube

Front 14

Latent Image

Back 14

invisible image created after exposure but before processing

Front 15

Milliampere Seconds (mAs)

Back 15

measurement of milliamperage times seconds, which controls the quantity of x-ray photons produced in the x-ray tube

Front 16

Penetrating Ability

Back 16

ability of an x-ray beam to pass through an object, controlled by the kVp of the beam

Front 17

Penumbra

Back 17

fuzzy border of an object as imaged radiographically

Front 18

Photon

Back 18

quantum or particle of radiant energy

Front 19

Positive Beam Limitation (PBL)

Back 19

automatic collimation system used on diagnostic x-ray units

Front 20

Primary Radiation

Back 20

x-ray beam after it leaves the x-ray tube and before it reaches the object

Front 21

Radiolucent

Back 21

permitting the passage of x-rays or other forms of energy with little attenuation

Front 22

Radiopaque

Back 22

not easily penetrable by x-rays or other forms of radiant energy

Front 23

Recorded Detail

Back 23

representation of an object's true borders

Front 24

Relative Speed

Back 24

relative measurements of the speed of a radiographic film and intensifying screen system

Front 25

Remnant Radiation

Back 25

radiation resulting after the x-ray beam exits the object

Front 26

Resolution

Back 26

a measurement of the recorded detail on a radiograph

Front 27

Scatter Radiation

Back 27

radiation produced from x-ray photon interactions with matter in such a way that the resulting photons have continued in a different direction

Front 28

Source-to-Image Distance (SID)

Back 28

the distance between the source of the x-rays (usually the focal spot of the x-ray tube) and the image receptor

Front 29

Static

Back 29

unmoving

Front 30

Umbra

Back 30

true border of an object as imaged radiographically

Front 31

Anode

Back 31

positive electrode of the x-ray tube

Front 32

Bucky Mechanism

Back 32

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

Front 33

Cassette

Back 33

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

Front 34

Cathode

Back 34

negative electrode of the x-ray tube

Front 35

Collimator

Back 35

diaphragm or system of diaphragms made of an absorbing material; designed to define the dimensions and direction of a beam of radiation

Front 36

Fluoroscope

Back 36

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

Front 37

Fluoroscopy

Back 37

examination by means of the fluoroscope

Front 38

Longitudinal

Back 38

lengthwise; along the long axis

Front 39

Spot Film Device

Back 39

equipment that permits the acquisition of static images during a dynamic fluoroscopic examination

Front 40

Transverse

Back 40

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

Front 41

Tube Angulation

Back 41

pivoting the tube at the point where it is attached to its support

Front 42

Vertical

Back 42

perpendicular to the plane of the horizon

Front 43

X-ray Tube

Back 43

device that produces x-rays