111- Recorded Detail And Distortion Test

Question 1

Define recorded detail and provide other terms used to express recorded detail

Answer 1

Degree of geometric sharpness/ accuracy of structural lines
Definition
Sharpness
Resolution
Spatial resolution

Question 2

What is the unit of resolution

Answer 2

Line pairs per mm

Question 3

Define umbra and penumbra

Answer 3

Umbra- sharp area

Penumbra- unsnarl area

Question 4

Define distortion and list the types of distortion

Answer 4

Misrepresentation of size or shape of part

Magnification, foreshortening, elongation

Question 5

What factors affect size distortion

Answer 5

OID and SID

Question 6

Explain how size distortion happens

Answer 6

Increased OID

Question 7

How does patient thickness affect distortion

Answer 7

Pt thickness adds inherent OID which can magnify structures

Question 8

What factors affect shape distortion

Answer 8

CR, IR, body part

Question 9

Explain how shape distortion happens

Answer 9

Poor alignment if CR, IR, Ir body part

Question 10

How will FSS, motion, OID and SID impact recorded detail

Answer 10

Decrease FSS increase detail
Decrease motion increase detail
Decrease OID increase detail
Increase SID increase detail

Question 11

What are the two photographic properties of radiography and the two geometric properties

Answer 11

Photographic- contrast and density

Geometric- detail and distortion

Question 12

List factors that affect visibility of detail

Answer 12

FSS, OID/SID, motion, kvp, mas

Question 13

How will changing from a small to large focal spot affect density

Answer 13

No effect

Question 14

How will changing from a small to large focal spot affect contrast

Answer 14

No effect

Question 15

How will changing from a small to large focal spot affect detail

Answer 15

Decrease detail

Question 16

How will changing from a small to large focal spot affect distortion

Answer 16

No effect

Question 17

What factors affect spatial resolution in digital imaging?

Answer 17

Matrix size, pixel size, grayscale bit depth

Question 18

In digital imaging, which axis represents height, width, and depth

Answer 18

Height - y
Width- x
Depth- z

Question 19

What is the difference between system noise and quantum noise

Answer 19

System- background frequency interference

Quantum- lack of Xray photons

Question 20

Describe how noise appears on an image

Answer 20

Grainy

Question 21

If an image displays quantum noise, what caused this

Answer 21

Underexposure

Question 22

How will you fix quantum noise on a digital image

Answer 22

Increase mas

Question 23

Which is best for demonstrating increased spatial resolution, a high or low SNR

Answer 23

High SNR

Question 24

As FSS decreases, what happens to umbra

Answer 24

Increases

Question 25

As FSS decreases, what happens to penumbra

Answer 25

Decreases

Question 26

As FSS decreases, what happens to resolution

Answer 26

Increases

Question 27

As FSS decreases, what happens to recorded detail

Answer 27

Increases

Question 28

How does FSS affect penumbra

Answer 28

Decrease FSS, decrease penumbra

Question 29

How does OID affect penumbra

Answer 29

Decrease OID decrease penumbra

Question 30

How does SID affect penumbra

Answer 30

Increase SID decrease penumbra

Question 31

How does size distortion affect resolution

Answer 31

Decreases resolution

Question 32

What is the best method for controlling involuntary motion

Answer 32

Short exposure time

Question 33

What is the best way for controlling voluntary motion

Answer 33

Clear instructions

Question 34

What is the last resort for controlling patient motion

Answer 34

Immobilization

Question 35

Which distance is most associated with pt skin dose and why

Answer 35

SOD, the closer the source is to pt, more radiation is absorbed

Question 36

Explain the relationship between a larger patient and entrance skin exposure

Answer 36

Bigger the patient, more ESE

Question 37

How does the shape of the body part affect penumbra

Answer 37

Shapes in the body that match beam divergence create the least penumbra

Question 38

What are two different formulas that can be used to calculate MF

Answer 38

SID/SOD | Image/object size

Question 39

Magnification occurs when the body part is moved closer to or farther away from the central ray

Answer 39

Closer

Question 40

Proper alignment is achieved when the central ray is ___ to the part and ____ to the image receptor

Answer 40

Perpendicular, perpendicular