CR DR MIDTERM

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 5

is a black line on a light background.

Answer 5

line pair.

Question 6

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

Answer 6

line pair.

Question 7

One line pair consists

Answer 7

line and an interspace of the same width as the line

Question 8

unit of line pair

Answer 8

lp/mm

Question 9

*An imaging system with higher spatial frequency has better

Answer 9

spatial resolution.

Question 10

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

Answer 10

difficult to image.

Question 11

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

Answer 11

easy to image.

Question 12

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

Answer 12

Modulation transfer function

Question 13

note

Answer 13

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

Question 14

two bar pattern test tools with spatial frequencies up to

Answer 14

20 lp/mm

Question 15

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

Answer 15

Contrast resolution

Question 16

The principal descriptor for contrast resolution is grayscale,

Answer 16

dynamic range.

Question 17

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

Answer 17

dynamic range.

Question 18

The dynamic range of digital imaging systems is identified by the

Answer 18

bit capacity of each pixel.

Question 19

CT and MRI system dynami range

Answer 19

12-bit dynamic range

Question 20

DR dynamic range

Answer 20

14

Question 21

Mammo dynamic range

Answer 21

16

Question 22

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

Answer 22

signal

Question 23

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

Answer 23

20% to 50%,

Question 24

Spatial resolution in screen-film radiography is determined principally by

Answer 24

focal-spot size.

Question 25

Spatial resolution in digital imaging is determined by

Answer 25

pixel size

Question 26

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

Answer 26

Analog image

Question 27

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

Answer 27

Digital image

Question 28

Critical characteristics of digital image:

Answer 28

*Spatial resolution *Contrast resolution *Noise *Dose efficiency

Question 29

Smallest element in a digital image.

Answer 29

PIXEL

Question 30

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

Answer 30

PIXEL

Question 31

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

Answer 31

Pixel size

Question 32

Number of bits within a pixel.

Answer 32

Pixel bit depth

Question 33

Represents the gray level.

Answer 33

Pixel bit depth

Question 34

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

Answer 34

MATRIX

Question 35

Amount of body part or patient included in the image.

Answer 35

FIELD OF VIEW

Question 36

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

Answer 36

EXPOSURE INDICATORS

Question 37

NOTE

Question 39

standard exposure typical of that imaging receptor system

Answer 39

Standardized radiation exposure (KSTD)

Question 40

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

Answer 40

Indicated equivalent air kerma (KIND)

Question 41

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

Answer 41

Target equivalent air kerma value (KTGT)

Question 42

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

Answer 42

Deviation index (DI)

Question 43

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 43

BRIGHTNESS

Question 44

BRIGHTNESS IS MEASURED BY

Answer 44

photometer.

Question 45

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

Answer 45

CONTRAST RESOLUTION

Question 46

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

Answer 46

CONTRAST RESOLUTION

Question 47

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

Answer 47

SPATIAL RESOLUTION

Question 48

PSP pixel size

Answer 48

200μm

Question 49

Gadolinium AMFPI size -

Answer 49

150μm

Question 50

Cesium iodide AMFPI size

Answer 50

50μm

Question 51

To quantify gain or loss of resolution,

Answer 51

Modulation Transfer Function

Question 52

Ability of a system to record available spatial frequencies

Answer 52

MTF

Question 53

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

Answer 53

1% or 100%.

Question 54

-Anything that interferes with the formation of the image.

Answer 54

NOISE

Question 55

occurs if body parts are superimposed

Answer 55

Anatomic noise

Question 56

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

Answer 56

Radiographic noise

Question 57

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

Answer 57

Equipment noise

Question 58

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

Answer 58

EXPOSURE LATITUDE

Question 59

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

Answer 59

DETECTIVE QUANTUM EFFICIENCY8