Digital Radiography And Pacs - Chap 4

Front 1

consists of a durable, lightweight plastic material; backed by a thin sheet of aluminum or lead that absorbs backscatter x-ray photons

Back 1

PSP cassette

Front 2

PSP

Back 2

photostimulable phosphor

Front 3

contains an antistatic material (usually felt) that protects against static electricity buildup, dust collection, and mechanical damage to the PSP plate

Back 3

PSP cassette

Front 4

a very thin, rough, clear plastic that protects the phosphor layer

Back 4

protective layer

Front 5

a layer of PSP that "traps" electrons during exposure; usually made of phosphors from the barium flourohalide family

Back 5

phosphor layer (or active layer)

Front 6

a layer that sends light in a forward direction when released in the cassette reader; may be black to reduce the spread of stimulating light and the escape of emitted light

Back 6

reflective layer

Front 7

a layer of material that absorbs and reduces static electricity

Back 7

conductive layer

Front 8

located between the active layer and support, that absorbs the stimulating light but reflects emitted light

Back 8

color layer

Front 9

a soft polymer that protects the back of the cassette

Back 9

backing layer

Front 10

allows the technologist to match the image information with the patient-ID barcode on the examination request

Back 10

barcode label

Front 11

how is the patient positioned with PSP systems?

Back 11

the same way as in conventional radiography, using appropriate positioning techniques, and the body part aligned with the IR

Front 12

in PSP, what does the remnant beam interact with?

Back 12

electrons in the barium fluorohalide crystals contained within the IR

Front 13

what interaction stimulates, or gives energy to, electrons in the crystals, trapping them in an area known as the color or phosphor center?

Back 13

the interaction of the remnant beam and electrons in the barium fluorohalide crystals contained within the imaging plate

Front 14

2 types of PSP readers

Back 14

point scan and line scan

Front 15

how is a PSP cassette read?

Back 15

without a chemical processor or darkroom, the cassette is fed into a reader that removes the imaging plate and scans it with a laser to release the stored electrons

Front 16

a device that creates and amplifies a narrow, intense beam of coherent light

Back 16

laser, or Light Amplification of Stimulated Emission of Radiation

Front 17

what are the characteristics of the laser beam that scans the plate with red light in a raster pattern and gives energy to the trapped electrons?

Back 17

about 100 micrometers wide with a wavelength or 633 nm (or 670 to 690 nm for solid state)

Front 18

how many eV is necessary to energize the trapped electrons by the red laser light emitted to read the imaging plate?

Back 18

2 eV

Front 19

the visible blue light is emitted at an energy of ____ as they relax into lower energy levels

Back 19

3 eV

Front 20

what is meant when talking about digitizing a signal, such as the light signal from a photodetector?

Back 20

assigning a numerical value to each light photon

Front 21

what is the time frame a digital clock is capable of representing?

Back 21

only a finite number of times (e.g., every tenth of a second)

Front 22

the amount of detail present in any image

Back 22

spatial resolution

Front 23

how often should imaging plates be erased to prevent a buildup of background signal?

Back 23

at least once a week

Front 24

how are imaging plates erased by the readers?

Back 24

by flooding it with light to remove any electrons still trapped after the initial plate reading

Front 25

how is image recognition accomplished in the part selection menu?

Back 25

through complex mathematical computer algorithms

Front 26

what is the consequence if improper part and/or position is entered in the part selection menu?

Back 26

the image may be processed incorrectly and fail to display properly

Front 27

what is the result when insufficient light produces a grainy image?

Back 27

quantum mottle or quantum noise

Front 28

a wavy artifact that occurs because the grid lines and the scanning laser are parallel

Back 28

moire pattern

Front 29

what blurs grid lines and eliminates interference?

Back 29

the oscillating motion of a moving grid, or Bucky

Front 30

the reduction of the area of beam that reaches the patient through the use of two pairs of lead shutters encased in a housing attached to the x-ray tube; results in increased contrast resolution as a result of the reduction of scatter

Back 30

collimation

Front 31

post-exposure image manipulation; a black background that can be added around the original collimation edges, virtually eliminating the distracting white or clear areas

Back 31

shuttering

Front 32

a graphic representation of the numerical tone of values of an x-ray exposure

Back 32

histogram

Front 33

term used by AGFA for image recognition

Back 33

collimation

Front 34

term used by Carestream for image recognition

Back 34

segmentation

Front 35

term used by Fuji for image recognition

Back 35

exposure data recognition

Front 36

any undesirable densities on the processed image other than those caused by scatter radiation or fog

Back 36

artifacts

Front 37

where images are sent to be analyzed and sent to the PACS for long-term storage

Back 37

QC station

Front 38

how is spatial resolution of the digital image determined?

Back 38

by the thickness of the phosphor layer and the size of the pixels; the thinner the phosphor layer, the greater the sharpness of the image, and the smaller the pixel size, the higher the spatial resolution

Front 39

collects light and sends it to a signal digitizer

Back 39

photodetector

Front 40

ADC

Back 40

analog-to-digital convertor

Front 41

assigns a numerical value to each pixel in a matrix according to the intensity of the detected light

Back 41

ADC

Front 42

A

Back 42

protective layer

Front 43

B

Back 43

light reflective layer

Front 44

C

Back 44

support layer

Front 45

D

Back 45

backing layer

Front 46

E

Back 46

phosphor layer

Front 47

F

Back 47

conductive layer

Front 48

G

Back 48

light shielding layer

Front 49

H

Back 49

barcode label