Recorded Detail Ch. 28

Question 1

Detail is AKA

Answer 1

Recorded detail, spacial resolution

Question 2

How many geometric properties of image quality?

Answer 2

2

Question 3

Geometric properties control…

Answer 3

detail itself

Question 4

What is the degree of geometric sharpness or accuracy of the structural lines actually recorded in the image?

Answer 4

recorded detail

Question 5

What is one of the easiest prime technical factors to evaluate & adjust?

Answer 5

recorded detail

Question 6

What is lp/mm?

Answer 6

the point at which the viewer can discern the closest pair of lines from each other

Question 7

How is recorded detail determined?

Answer 7

primarily by matrix size, pixel size and grayscale bit depth

Question 8

High resolution is …

Answer 8

a shorter wavelength signal (higher frequency) represents pairs of lines that can be visualized very close together

Question 9

What would be easier to see the spacial resolution..a small or large body part?

Answer 9

small

Question 10

When fine detail is lacking the image will look

Answer 10

blurred

Question 11

What order should resolution problems be approached?

Answer 11

1. eliminate motion
2. reduce OID
3. Reduce FSS
4. Reduce intensifying screen phosphor size and concentration
5. Increase SID

Question 12

What is the most important factor in establishing the level of resolution desired for recorded detail?

Answer 12

the geometry of the beam (divergence of the beam)

Question 13

What happens to resolution when OID is decreased, increased?

Answer 13

Improves, degrades

Question 14

What happens to resolution when SID is decreased, increased?

Answer 14

degrades, improves

Question 15

Why is the lateral C-spine done at 72”?

Answer 15

B/c you cannot reduce OID so you must increase SID to get better detail/less magnification.

Question 16

What is FSS controlled by?

Answer 16

the line focus principle

Question 17

What is the umbra?

Answer 17

the distinctly sharp area of a shadow or region of complete shadow

Question 18

What is the penumbra?

Answer 18

the imperfect, unsharp shadow surrounding the umbra

Question 19

Penumbra is also referred to as..

Answer 19

the edge gradient

Question 20

What controls penumbra?

Answer 20

FSS

Question 21

What causes penumbra?

Answer 21

the fact that the source of the xray photons is not a point source.

Question 22

As FSS decreases, penumbra…

Answer 22

also decreases & increases resolution

Question 23

Other than increased FSS, decreased SID and increased OID, what could cause increased penumbra?

Answer 23

attenuation or absorption unsharpness

Question 24

What is better for detail in F/S…fast or slow film speed?

Answer 24

slow!

Question 25

What are the primary factors affecting the recorded detail of digital imaging systems?

Answer 25

the detector geometric properties and image processing system

Question 26

What is the #1 cause of decreased detail?

Answer 26

Motion

Question 27

What is the best way of controlling voluntary motion?

Answer 27

communication

Question 28

What is the best way to control involuntary motion?

Answer 28

Decrease exposure time

Question 29

How does the xray machine cause motion?

Answer 29

movement of the reciprocating grid, if the suspension system is not balanced - both can vibrate

Question 30

What is SOD?

Answer 30

source to object distance

Question 31

How do you calculate SOD?

Answer 31

SID-OID=SOD

Question 32

How do you calculate FSS?

Answer 32

OID/SOD

Question 33

How do you calculate penumbra?

Answer 33

FSS x OID / SOD

Question 34

smaller pixels =

Answer 34

sharper image

Question 35

What is the Focal spot?

Answer 35

the exact point on the target or target track on the anode where xrays are produces

Question 36

Why are kidneys imaged AP?

Answer 36

B/c the kidneys are retroperitoneal

Question 37

What are picture elements of certain densities?

Answer 37

pixels

Question 38

Overexposure and underexposure reduces

Answer 38

detail