Digital Imaging

Question 1

Two Step process for image capture and readout;
uses imaging plate (IP)

Answer 1

Computed radiography (CR)

Question 2

Combined image capture and readout; uses flat panel detectors

Answer 2

Direct radiography (DR)

Question 3

Individual picture elements in CR

Answer 3

Pixel

Question 4

Matrix size in CR

Answer 4

Field of view (collimation)

Question 5

_____ pixel size = better image quality in CR

Answer 5

smaller

Question 6

Demonstrates exposure range (S number)

Answer 6

Exposure index

Question 7

Two step process for CR

Answer 7

image capture and image readout

Question 8

In CR, the image receptor houses the:

Answer 8

imaging plate (IP)

Question 9

Absorbs x-rays in CR

Answer 9

IP phosphor

Question 10

Converts latent image into electric signal that can be digitized

Answer 10

CR reader

Question 11

3 stages on a CR reader:

Answer 11

scanning, sampling, quantization

Question 12

Laser scanning of the exposed IP converts the ____ into an ______.

Answer 12

released energy (visible light); electrical signal (voltage)

Question 13

The photodetector collects, amplifies, and converts the _____ to an _____ proportional to the range of energies stored in the IP

Answer 13

visible light; electrical signal

Question 14

How often the analog signal is reproduced in its digitized form on CR imaging

Answer 14

Sampling frequency

Question 15

Distance between sampling points on CR imaging

Answer 15

Sampling pitch

Question 16

Each pixel brightness value on CR image is assigned a numerical number:

Answer 16

quantization

Question 17

number of grey shades on CR image (contrast resolution)

Answer 17

Pixel depth

Question 18

Integrated into the flat-panel device in DR

Answer 18

Signal storage, signal readout, digitizing electronics

Question 19

Top layer of flat panel detector

Answer 19

X-ray converter

Question 20

second layer of flat panel detector

Answer 20

TFT tray

Question 21

third layer of flat panel detector

Answer 21

glass substrate

Question 22

Two types of conversion that flat panel detectors use

Answer 22

indirect/direct

Question 23

radiation to visible light, light to electrical charge, electric signal sent to ADC for digitization

Answer 23

Indirect conversion

Question 24

Made up of rows/columns of individual pixels

Answer 24

Matrix

Question 25

number of bits; number of shades of gray

Answer 25

Pixel bit depth

Question 26

Every pixel value of an image would demonstrate the photo's:

Answer 26

Histogram

Question 27

X-axis of an image's histogram:

Answer 27

Pixel value

Question 28

Y-axis of an image's histogram:

Answer 28

Pixel count

Question 29

Exposure histogram is compared to a:

Answer 29

reference histogram

Question 30

An image formed by recording a continuous changing signal is known as

Answer 30

Analog

Question 31

Which of the following measures the efficiency of a system to convert the x-ray input signal into a useful output image?

Answer 31

DQE

Question 32

The useful signal is determined during which part of the imaging cycle?

Answer 32

Image sampling

Question 33

In digital projection radiography, what process is used to normalize an image that has been taken with too great of an exposure?

Answer 33

Automatic rescaling

Question 34

Which processing technique will amplify particular known frequencies in an image while suppressing others? a. Edge enhancement b. High-pass filtering c. Masking d. All of the above.

Answer 34

D

Question 35

The active layer in a PSP plate is usually made of phosphors from what family group?

Answer 35

Barium fluorohalide

Question 36

What device in the reader detects the light being released from the PSP plate during reading?

Answer 36

Photodetector

Question 37

T/F: Dark line artifacts can be caused by too much kVp in an exposure.

Answer 37

True

Question 38

What does a photoconductor do?

Answer 38

absorbs x-rays and produces electrical charges.

Question 39

A charge-coupled device (CCD) does all of the following except: a. Reduce the size of the projected light image b. Transfer the image to a capacitor c. Convert light into X-ray photons d. Act as receptors via lenses or fiber optics

Answer 39

C

Question 40

T/F: Digital systems are more sensitive to scatter radiation

Answer 40

True

Question 41

What component of the CR reader converts light to an electric signal?

Answer 41

photodetector

Question 42

When x-rays strike the PSP material, ____ is released

Answer 42

Light

Question 43

T/F: The LUT is unique for each anatomic part

Answer 43

True

Question 44

Europium serves as:

Answer 44

An activator for the phosphor

Question 45

Two methods for indirect capture DR include:

Answer 45

Charged couple device TFT arrays + scintillator

Question 46

DR converts x-rays into:

Answer 46

Electrons

Question 47

The scintillator for the indirect capture DR system using CCD that is made of

Answer 47

Cesium iodide

Question 48

T/F: After the digital data leaves the ADC, the process of image formation is very different for the 3 types of DR systems

Answer 48

False

Question 49

The ability of phosphors to emit visible light when exposed to x-rays

Answer 49

Fluorescence

Question 50

PSP stands for:

Answer 50

Photostimulable Phosphor

Question 51

Intensifying screens are used to:

Answer 51

Decrease patient exposure

Question 52

The type of image receptor (IR) that uses a photostimulable phosphor to acquire the latent image is ________________.

Answer 52

Computed radiography

Question 53

What is used to extract the latent image from an imaging plate (IP)?

Answer 53

Laser beam

Question 54

T/F: Digital imaging systems have a wide dynamic range.

Answer 54

True

Question 55

T/F: A 16-bit digital system would have a narrow dynamic range compared to a 12-bit system.

Answer 55

False

Question 56

What provides an indication of patient radiation risk during a radiographic procedure?

Answer 56

DAP and KAP

Question 57

Digital detectors that require a two-stage process to acquire and digitize the latent image include A. flat-panel detectors indirect conversion. B. CCD. C. CMOS. D. all the above.

Answer 57

D

Question 58

The exposure latitude of digital projection radiography responds in a _______ manner.

Answer 58

Linear

Question 59

Which radiographic image capture method uses an x-ray absorber material coupled to a thin film transistor or a charge-coupled device (CCD) to form the digital radiographic image?

Answer 59

FPD