digital systems

Question 1

film-type radiograph

Answer 1

analog

Question 2

smallest component of the matrix; a greater number of smaller ______ improves spatial resolution; “picture elements”

Answer 2

pixels

Question 3

image displayed as a combination of rows and columns (array)

Answer 3

matrix

Question 4

number of bits that determines the precision with which the exit radiation is recorded and controls the exact pixel brightness that can be displayed

Answer 4

pixel bit depth

Question 5

pixel size is _____ related to the FOV and _____ to the matrix size

Answer 5

directly, inversely

Question 6

the greater the pixel bit depth, the _________ the digitization of analog signal and the _________ the number of shades of gray available for image display

Answer 6

more precise; greater

Question 7

increasing pixel bit depth _______ contrast resolution

Answer 7

increases

Question 8

CR has ___; DR has ____

Answer 8

2 steps, 1 step

Question 9

the IP in computed radiography layers in a cross section

Answer 9

protective layer
phosphor layer (turbid)
reflective layer
conductive layer
support layer

Question 10

types of phosphor layers

Answer 10

turbid (random), structured (columnar)

Question 11

three stages of CR processing

Answer 11

scanning, sampling quantization

Question 12

what type of laser is the CR reader?

Answer 12

neon helium laser

Question 13

how often the analog signal is reproduced in its digitized form

Answer 13

sampling frequency

Question 14

distance between sampling points

Answer 14

sampling pitch

Question 15

equation for analog to digital conversion

Answer 15

Nyquist frequency

Question 16

each pixel brightness value is assigned a numerical number

Answer 16

quantization

Question 17

number of gray shades (contrast resolution)

Answer 17

pixel depth

Question 18

Laser scanning of the exposed IP converts the released energy (_______) into an electrical signal (______)

Answer 18

visible light, voltage

Question 19

indirect conversion utilizes a ______________ detector that converts exit radiation to _______; the __________ then converts this to a _________________

Answer 19

scintillator type, visible light, photodetector, electrical charges

Question 20

direct conversion utilizes ____________________ detector converts exit radiation directly into ____________-

Answer 20

amorphous selenium-coated, electrical charges

Question 21

which sends electrical signal to an analog to digital converter?

Answer 21

both direct and indirect conversion

Question 22

solid state IRs that use a large area active matrix array of electronic components

Answer 22

flat panel detectors (FPDs)

Question 23

for best image quality, you want _____ matrix with ______ pixel size

Answer 23

large, small

Question 24

graphic representation of a data set

Answer 24

histogram

Question 25

histogram x-axis

Answer 25

X-axis = range of pixel values

Question 26

histogram y-axis

Answer 26

y -axis = number of pixels in that range

Question 27

names for exposure indicators

Answer 27

S number, EI, Z number

Question 28

this provides a method of processing the image data, based on the reference histogram, to transform the image data into a quality image for display

Answer 28

lookup table (LUTs)

Question 29

LUTs provide the means to alter the ___________ to improve the brightness and contrast of the displayed image

Answer 29

original pixel values

Question 30

a post processing technique that can remove superimposed structures so that the anatomic area of interest becomes more visible

Answer 30

dual-energy subtraction

Question 31

post-processing technique that suppresses image noise (quantum noise)

Answer 31

smoothing

Question 32

post-processing function whereby underexposed areas (light areas) are made darker and overexposed areas (dark areas) are made lighter

Answer 32

equalization

Question 33

high-pass filtering is another term for _________

Answer 33

edge enhancement

Question 34

post-processing technique that improves the visibility of small, high-contrast structure

Answer 34

edge enhancement

Question 35

post-processing technique that reverses the grayscale from original imaging

Answer 35

inversion

Question 36

low-pass filtering is another term for __________

Answer 36

smoothing

Question 37

window level is for ________

Answer 37

brightness

Question 38

window width is for ______

Answer 38

contrast

Question 39

HIS stands for

Answer 39

hospital information system

Question 40

RIS stands for

Answer 40

radiology information system

Question 41

EHR stands for

Answer 41

electronic health record

Question 42

PACS stands for

Answer 42

picture archival and communication system

Question 43

DICOM stands for

Answer 43

digital imaging and communications in medicine

Question 44

S numbers are (inverse/direct)

Answer 44

inverse

Question 45

a larger matrix size _____ spatial resolution

Answer 45

Improves

Question 46

increasing pixel density (increases/decreases) spatial resolution

Answer 46

increases

Question 47

decreasing pixel pitch (increases/decreases) spatial resolution

Answer 47

decreases

Question 48

post processing technique that alters pixel values to change contrast

Answer 48

contrast enhancement

Question 49

what does PACS stand for?

Answer 49

pictural archival and communication system

Question 50

what does DICOM stand for?

Answer 50

Digital Imaging and Communications in Medicine

Question 51

material used in phosphor layer in CR plates

Answer 51

barium halide with europium

Question 52

material used in DR scintillator detectors

Answer 52

cesium iodide OR gadolinium oxide

Question 53

material used in DR CCD detectors

Answer 53

cesium iodide

Question 54

material used in DR CMOS detectors

Answer 54

crystalline silicon

Question 55

material used in DR direct conversion detectors

Answer 55

amorphous selenium