Basic Principles of Digital Radiography

Question 1

pixel

Answer 1

picture element

Question 2

these small little dots are what make up the images on computer displays, whether they are flat screen or tube monitors

Answer 2

pixel/picture element

Question 3

it is the cell of a digital image matrix

Answer 3

pixel/picture element

Question 4

are the horizontal and vertical measurements of an image expressed in pixels

Answer 4

pixel dimensions

Question 5

it is the amount of resolution in an image is determined by the size of the pixels and the spacing between them or pixel pitch

Answer 5

pixel size/matrix size

Question 6

PACS

Answer 6

picture archival and communication system

Question 7

how many pixels in a row are adequate for most diagnostic examinations?

Answer 7

2000 pixels/row

Question 8

it consists of a photoconductor, amorphous selenium, which holds a charge on its surface that can then be read out by a TFT

Answer 8

flat panel detectors

Question 9

in _____ ________, xray photons are absorbed by the coating material and immediately converted into an electrical signal

Answer 9

direct conversion

Question 10

TFT

Answer 10

thin film transistor

Question 11

it is a photosensitive array made up of small pixels. each pixel contains a photodiode that absorbs the electrons and generates electrical charges

Answer 11

thin film transistor (TFT)

Question 12

each pixel contains a________ that absorbs the electrons and generates electrical charges

Answer 12

photodiode

Question 13

FET

Answer 13

field effect transistor

Question 14

field effect transistor or _____ TFT

Answer 14

field effect transistor or silicon TFT

Question 15

it isolates each pixel element and reacts like a switch to send the electrical charges to the image processor

Answer 15

field effect transistor (FET)
or
silicon TFT

Question 16

it is a two step process: xray photons are converted to light and then the light photons are converted to an electrical signal

Answer 16

indirect conversion detectors

Question 17

a ______ converts xray into visible light

Answer 17

scintillator

Question 18

CCD

Answer 18

charge-coupled device

Question 19

this type of flat panel sensor uses thin films of silicon integrated with arrays of photodiodes

Answer 19

amorphous silicon detector

Question 20

the oldest indirect conversion DR system is based on ______ ________ ________

Answer 20

the oldest indirect conversion DR system is based on charge coupled devices (CCDs)

Question 21

it acts like cameras that reduces the size of the projected visible light image and transfer the image to one or more small CCDs that convert the light into electrical charge

Answer 21

fiberoptics

Question 22

DQE

Answer 22

detective quantum efficiency

Question 23

it is one of the fundamental physical variables related to image quality in radiography and refers to the efficiency of a detector in converting incident xray energy into an image signal

Answer 23

detective quantum efficiency (DQE)

Question 24

SNR

Answer 24

signal to noise ratio

Question 25

it refers to the amount of error that can be made and still result in the capture of a quality image

Answer 25

latitude

Question 26

what is the result if the exposure in CR is more than 50% below the ideal exposure?

Answer 26

quantum mottle

Question 27

what is the result if the exposure is more than 200% above the ideal exposure?

Answer 27

contrast loss