DR

Question 1

TFT

Answer 1

Thin film transistor

Question 2

CCD

Answer 2

Charge coupled device

Question 3

AMA

Answer 3

Active matrix array

Question 4

ADC

Answer 4

Analog digital conversion

Question 5

DEL

Answer 5

Detector element

Question 6

What are some advantage of DR?

Answer 6

Faster

No physical storage space required

Post processing allows for post acquisition alterations

Reduce patient radiation dose

Question 7

What are the 3 elements of digital radiography?

Answer 7

Capture element
Coupling element
Collection element

Question 8

What are possible materials for the capture element in DR?

Answer 8

Sodium iodide (NaI)
Cesium iodide (CsI)
Gadolinium oxysulfide (GdOS)
Amorphous selenium (a-Se)

Question 9

Transfers the xray generated signal to the collection element

Answer 9

Coupling element

Question 10

What are typical detector dimensions for DR?

Answer 10

43x43cm
43x35cm

Question 11

What is the typical pixel dimension in a digital detector?

Answer 11

139-200 um
Micrometers

Question 12

What are possible coupling elements?

Answer 12

Lens or fibre optic assembly

A contact layer

a-Se

Question 13

What are possible collection elements?

Answer 13

Photodiode

Charge coupled device (CCD)

Thin film transistor (TFT)

Question 14

Which collection elements are light sensitive devices that collect light photons?

Answer 14

Photodiode and CCD

Question 15

Which collection element is a charge sensitive device that collects electrons?

Answer 15

TFT

Question 16

What is the capture element in CR?

Answer 16

Photostimuable phosphor (PSP)

Question 17

What causes exit radiation to create an electric charge?

Answer 17

Interaction with the detector
The pattern of the electric charge constitutes the latent image

Question 18

Array of CCDs or TFTs with an xray absorption material

Answer 18

Active matrix array (AMA)

Question 19

Converts xray photons to an electrical charge

Answer 19

Photoconductors

Question 20

Converts xray energy to light photons

Answer 20

Scintillators

Question 21

What are the two main types of xray absorption materials

Answer 21

Photoconductors and scintillators

Question 22

What is the absorption material attached?

Answer 22

To the surface of the AMA
*array measures xray absorption rather than counting/measuring the actual X-rays

Question 23

The conversion of X-rays, either direct or indirect is based on what?

Answer 23

The xray absorption material

Question 24

What are the 3 elements of a DR detector?

Answer 24

Capture element
Coupling element
Collection element

Question 25

The way in which X-rays are captured

Answer 25

Capture element (CsI, GdOS, a-se)

Question 26

Transfers cray generated signal to the collection element

Answer 26

Coupling element (Lens or fibre optics, contact layer, a-se)

Question 27

What material can act as a capturing or coupling element?

Answer 27

a-se

Question 28

Collects light photons or electrons?

Answer 28

Collection element (Photodiode, charged coupling device, thin film transistor)

Question 29

What two collection elements are light sensitive devices that collect light photons?

Answer 29

Photodiode, charged coupled device

Question 30

Which collection element is a charge sensitive device that collects electrons?

Answer 30

Thin film transistor

Question 31

What is the capture element for indirect (CCD)?

Answer 31

CsI

Question 32

What form of indirect DR uses fiber optics for a coupling element?

Answer 32

Indirect (CCD)

Question 33

Deposited as powdered particles Turbid/unstructured phosphor

Answer 33

GdOS (Reduces spatial resolution)

Question 34

Crystals are deposited in a needle like fashion perpendicular to detector surface Structures phosphor

Answer 34

CsI Higher DQE and spatial resolution

Question 35

Collects and stores electrical charge

Answer 35

Thin film transistor (TFT) *charge produced as a matrix of detector elements(DEL)

Question 36

T/F The term thin film transistor and flat panel detector are interchangeable

Answer 36

True

Question 37

T/F The maximum possible surface area is wanted for capture element to increase effectiveness

Answer 37

True

Question 38

T/F Detectors use about 2.5km of electrical bias, control, and data lines in the TFT

Answer 38

True

Question 39

Each row of pixels is connected to what line?

Answer 39

The same horizontal control line

Question 40

Each column is connected to which line?

Answer 40

The same vertical data line

Question 41

The ratio of sensing area of the pixel to the area of the pixel itself

Answer 41

Fill factor

Question 42

What are the 3 components that the pixel contains

Answer 42

TFT Storage capacitor Sensing area

Question 43

T/F As pixel size is reduced, spatial resolution increases, but fill factor decreases

Answer 43

True

Question 44

T/F A smaller fill factor decreases efficiency and effectiveness

Answer 44

True

Question 45

Requires scintillating screen to convert X-rays to light

Answer 45

Indirect (CCD)

Question 46

What is used to focus light onto the CCD chip in indirect DR?

Answer 46

Lenses or fibre optics *optics in a CCD a critical contributors to the quality of a digital image

Question 47

What does the CCD chip consist of, and what does it represent?

Answer 47

A series of semiconductor capacitors. Each capacitor represents a pixel

Question 48

T/F Spatial resolution in DR is pixel limited

Answer 48

True

Question 49

Information is read out row by row by via the changing of the _______

Answer 49

Control line voltage