Radiation Imaging PPT

Question 1

Faithfully reproducing the object’s structure and tissues

Answer 1

Quality

Question 2

4 quality characteristics:

Answer 2

Spatial Resolution

Contrast Resolution

Noise

Artifacts

Question 3

ability to distinguish two separate objects and visually distinguish them from one another

Answer 3

resolution

Question 4

Spatial resolution is defined by ___

Answer 4

line pairs/mm

Question 5

property of being noticeably different

Answer 5

contrast

Question 6

large density difference between lines

Answer 6

high contrast

Question 7

unwanted, non-useful signal obscures (hides) the useful signal

Answer 7

noise

Question 8

4 categories of noise:

Answer 8

1. Graininess
2. Structure mottle
3. Quantum mottle
4. Scatter Radiation

Question 9

___ pixel size = More detail = ___ noise

Answer 9

Smaller, less

Question 10

Irregular arrangement of spots or patches

Answer 10

mottle

Question 11

2 types of mottle:

Answer 11

1. structure mottle
2. quantum mottle

Question 12

What type of mottle?

Spots/smears - similar to graininess; structure of intensifing screen; dependent on imaging system

Answer 12

structure mottle

Question 13

What type of mottle?

Random nature of radiation interaction with detector. Dependent on number of photons (quanta).

Answer 13

qunatum mottle

Question 14

More quant (photons), ___ quantum mottle

Answer 14

less

Question 15

Type of mottle that looks like a photo taken with poor lighting.

Answer 15

quantum mottle

Question 16

____ mottle happens when x-ray is cut short (not enough photons)

Answer 16

quantum

Question 17

___ “fogs” the image

Answer 17

scatter radiation

Question 18

In scatter radiation, the image improves if you ___.

Answer 18

Move the image detector closer to the patient.

Question 19

irregularity on an image that is not caused by the proper shadowing of tissue by the primary x-ray beam

Answer 19

artifact

Question 20

3 types of artifacts:

Answer 20

1. Image Detector Artifacts
2. Software Artifacts
3. Object Artifacts

Question 21

____ artifacts: problems with image receptor, including, Dirt, Scratches, Pixel malfunction, Ghost images

Answer 21

image detector

Question 22

software artifacts can result from problems with: (3)

Answer 22

1. range/scaling
2. image compression
3. window and level

Question 23

Solution to image compression software artifact:

Answer 23

lossless compression (all data is retained, redundant data is compressed)

Question 24

3 types of object artifacts:

Answer 24

1. Patient Positioning
2. Collimator
3. Backscatter

Question 25

Magnification problem: ___ detail.

Answer 25

loses (gets mottled, so quality decreases)

Question 26

Mag factor equation:

Answer 26

𝑀𝐹= (𝐼𝑚𝑎𝑔𝑒 𝑆𝑖𝑧𝑒)/(𝑂𝑏𝑗𝑒𝑐𝑡 𝑆𝑖𝑧𝑒)

Question 27

MF = SID/SOD, what are SID and SOD

Answer 27

SID = source to image distance SOD = source to object distance

Question 28

Mag factor: Near Objects appear \_\_\_, while Far Objects appear \_\_\_\_

Answer 28

larger, smaller

Question 29

This image illustrates what?

Answer 29

Closer objects appear larger and far objects appear smaller

Question 30

This image illustrates what?

Answer 30

Closer images appear larger and far images appear smaller

Question 31

What are the solutions for distortion from magnification? (2)

Answer 31

1. adjust distance to detector 2. adjust source to object distance

Question 32

This illustrates the geometric factor ___ that depends on \_\_\_. What is the solution?

Answer 32

distortion, thickness, reduce distance to detector

Question 33

Geometric factors affecting imaging quality: (3)

Answer 33

1. magnification 2. distortion 3. focul spot blur

Question 34

This illustrates the geometric factor ___ that depends on \_\_\_. What is the solution?

Answer 34

distortion, position, get multiple image angles

Question 35

This illustrates the geometric factor ___ that depends on \_\_\_. What is the solution?

Answer 35

distortion, position, get multiple image angles

Question 36

This illustrates the geometric factor ___ that depends on \_\_\_. What is the solution?

Answer 36

distortion, position, get multiple image angles

Question 37

The best position to resolve geometric distortion is at \_\_.

Answer 37

isocenter

Question 38

This image illustrates the geometric factor \_\_\_. What is the solution?

Answer 38

focal spot blur, small source size, patient close to imager

Question 39

Patient factors in imaging quality: (2)

Answer 39

Contrast Motion

Question 40

The thicker the patient, the __ scatter you will get.

Answer 40

more

Question 41

What is the solution for patient thickness?

Answer 41

Increase the dose to the detector

Question 42

Solution for patient motion artifacts causing blurred image: (4)

Answer 42

1. shorten imaging time (may be moving bc of pain) 2. restrict pt motion 3. image detector close to pt 4. gating

Question 43

This picture illustrates a ___ image, due to \_\_\_.

Answer 43

blurred, patient motion

Question 44

EPID is located?

Answer 44

mounted on gantry head

Question 45

EPID uses ____ technology, is a ___ detector and is \_\_\_-based.

Answer 45

amourphous Si, digital, video