Fluoroscopy

Question 1

Function of the image intesifier

Answer 1

Coverts low energy xrays into visible light images

Question 2

6 parts of the image intensifier

Answer 2

1. Input phosphor
2. Photocathode Layer
3. Tube Potential
4. Electrostatic Focusing Lens
   5.Accelerating Anode
   6.Output Phosphor

Question 3

What is the input phosphor made of

Answer 3

Cesium iodide

Question 4

What part of the intensifier receives the xray beam

Answer 4

Input phosphor

Question 5

What is the photocathode layer made of

Answer 5

Cesium antimony

Question 6

What is the function of the photocathode layer

Answer 6

Photons converted to electrons

Question 7

How are electrons accelerated to anode

Answer 7

25-30kv potential difference

Question 8

What is the function of the electrostatic focusing lenses

Answer 8

Force the electrons into a concentrated stream as they accelarate towards the anode

Question 9

What is the output phosphor made of

Answer 9

Zinc Cadmium Sulfide

Question 10

Is input or output phosphor larger?

Answer 10

Input

Question 11

What charge do the electrostatic focusing lenses hold

Answer 11

Negative

Question 12

Function of output phosphor

Answer 12

Absorbs electrons and converts to light

Question 13

The ability of an image intensifier tube to convert radiation into light

Answer 13

Brightness gain

Question 14

Ratio of number of light photons at the output phosphor to the number of xray photons at the input phosphor

Answer 14

Flux gain

Question 15

What type of tube system is used with the image intensifier

Answer 15

Vidicom or Plumbicon
More modern systems use Solid-State CCD

Question 16

Occurs when the same number of electrons which were produced at the large input phosphor are compressed into the smaller area of the output phosphor

Answer 16

Minificiation gain

Question 17

The image intensifier creates a brighter image by taking fewer xray photons and converting that energy to more light photons

Answer 17

Flux gain

Question 18

Represents tubes coversion efficiency

Answer 18

Flux gain

Question 19

Relationship between Brightness gain, minification gain, and flux gain

Answer 19

Direct

Question 20

How are photons converted to electrons in the image intensifier

Answer 20

Photoemission

Question 21

When operating in mag mode, voltage to the focusing lens within the intensifier is increased or decreased?

Answer 21

Increased

Question 22

How does mag mode effect patient dose?

Answer 22

Increases

Question 23

What happens to the focal point in mag mode?

Answer 23

Moves further from output phosphor

Question 24

How does mag mode affect FOV

Answer 24

Reduces FOV

Question 25

How does mag mode affect spatial resolution

Answer 25

Increases

Question 26

What is the highest pulse rate used in fluoro

Answer 26

30 fps

Question 27

Is mA high or low when using pulsed fluoro

Answer 27

Low because of continous exposure

Question 28

For stationary fluoro units, source-to-skin distance sould be no less than:

Answer 28

38 cm

Question 29

For mobile/c-arm units, source-to-skin distance should be less than:

Answer 29

30 cm

Question 30

Fluoroscopy uses what type of grids

Answer 30

Stationary
Focused grids

Question 31

Grid ratio ranges for fluoro

Answer 31

4.5:1 - 10:1