CR-DR MIDTERMS

Question 1

Most people can see objects as small

Answer 1

200 um

Question 2

is described by the quantity “spatial frequency”.

Answer 2

spatial resolution

Question 3

dots were not high contrast, the spatial resolution of the eye would require

Answer 3

larger dots.

Question 4

ability of an imaging system to resolve and render on the image a small high-contrast object.

Answer 4

Spatial Resolution

Question 4

is a black line on a light background.

Answer 4

line pair.

Question 5

concept of spatial frequency does not refer to size but to the

Answer 5

line pair.

Question 6

One line pair consists

Answer 6

line and an interspace of the same width as the line

Question 7

unit of line pair

Answer 7

lp/mm

Question 8

*An imaging system with higher spatial frequency has better

Answer 8

spatial resolution.

Question 9

Bone trabeculae, breast microcalcifications, and contrast-filled vesselsare high-frequency objects; therefore, they are more

Answer 9

difficult to image.

Question 9

large soft tissues such as the liver, kidneys, and brain have low spatial frequency and therefore

Answer 9

easy to image.

Question 10

ability of an imaging system to render objects of different sizes onto an image

Answer 10

Modulation transfer function

Question 11

note

Answer 11

This is just another way of saying that small objects are harder to image.

Question 12

two bar pattern test tools with spatial frequencies up to

Answer 12

20 lp/mm

Question 13

is the ability to distinguish many shades of gray from black to white.

Answer 13

Contrast resolution

Question 14

The principal descriptor for contrast resolution is grayscale,

Answer 14

dynamic range.

Question 15

is the number of gray shades that an imaging system can reproduce

Answer 15

dynamic range.

Question 16

The dynamic range of digital imaging systems is identified by the

Answer 16

bit capacity of each pixel.

Question 17

CT and MRI system dynami range

Answer 17

12-bit dynamic range

Question 18

DR dynamic range

Answer 18

14

Question 19

Mammo dynamic range

Answer 19

16

Question 20

portion of the image-forming x-rays that represents anatomy.

Answer 20

signal

Question 21

With acceleration to all-digital imaging, we have the opportunity to reduce patient doses by

Answer 21

20% to 50%,

Question 22

Spatial resolution in screen-film radiography is determined principally by

Answer 22

focal-spot size.

Question 23

Spatial resolution in digital imaging is determined by

Answer 23

pixel size

Question 24

type of image such as paintings and printed photographs. Presents various levels of brightness and colors.

Answer 24

Analog image

Question 25

recorded as multiple numeric values and are divided into an array of small elements that can be processed in many different ways

Answer 25

Digital image

Question 26

Critical characteristics of digital image:

Answer 26

*Spatial resolution *Contrast resolution *Noise *Dose efficiency

Question 27

Smallest element in a digital image.

Answer 27

PIXEL

Question 28

-Contains the smallest divisible component of a digital image (bit).

Answer 28

PIXEL

Question 29

Directly related to the amount of spatial resolution or detail in the image

Answer 29

Pixel size

Question 30

Number of bits within a pixel.

Answer 30

Pixel bit depth

Question 31

Represents the gray level.

Answer 31

Pixel bit depth

Question 32

-A square arrangement of numbers (pixel values) in columns and rows.

Answer 32

MATRIX

Question 33

Amount of body part or patient included in the image.

Answer 33

FIELD OF VIEW

Question 34

- Refers to the amount of exposure received by the IR, not by the patient

Answer 34

EXPOSURE INDICATORS

Question 35

NOTE

Question 37

standard exposure typical of that imaging receptor system

Answer 37

Standardized radiation exposure (KSTD)

Question 38

measurement of the radiation that was incident on the IR for that particular exposure.

Answer 38

Indicated equivalent air kerma (KIND)

Question 39

set of values, established by either the system manufacturer or the system user,

Answer 39

Target equivalent air kerma value (KTGT)

Question 40

the difference between the actual exposure (KIND) and the target exposure (KTGT),

Answer 40

Deviation index (DI)

Question 41

Refers to its appearance on the display monitor of the computer and is a function of the monitor’s ability to emit light through the surface of the display

Answer 41

BRIGHTNESS

Question 42

BRIGHTNESS IS MEASURED BY

Answer 42

photometer.

Question 43

Refers to the ability of the digital system to display subtle changes in the shade of gray.

Answer 43

CONTRAST RESOLUTION

Question 44

Directly related to the bit depth of the pixels in the image

Answer 44

CONTRAST RESOLUTION

Question 45

Refers to the ability of the imaging system to demonstrate small details on an object

Answer 45

SPATIAL RESOLUTION

Question 46

PSP pixel size

Answer 46

200μm

Question 47

Gadolinium AMFPI size -

Answer 47

150μm

Question 48

Cesium iodide AMFPI size

Answer 48

50μm

Question 49

To quantify gain or loss of resolution,

Answer 49

Modulation Transfer Function

Question 50

Ability of a system to record available spatial frequencies

Answer 50

MTF

Question 51

ratio of the image to the object; thus a perfect system would have an MT OF ____

Answer 51

1% or 100%.

Question 52

-Anything that interferes with the formation of the image.

Answer 52

NOISE

Question 53

occurs if body parts are superimposed

Answer 53

Anatomic noise

Question 54

occurs during the acquisition of the images. Comprises of equipment noise and quantum noise.

Answer 54

Radiographic noise

Question 55

from noise in the detector elements and non-uniform detector responses.

Answer 55

Equipment noise

Question 56

Refers to the range of exposure diagnostic image values the image detector is able to produce.

Answer 56

EXPOSURE LATITUDE

Question 57

How efficiently a system converts the x-ray input signal into a useful output image.

Answer 57

DETECTIVE QUANTUM EFFICIENCY8