Image Intensified Fluoroscopy

Question 1

To aid the radiologist dynamic studies of the human body, “real time” imaging

Answer 1

Fluoroscopy

Question 2

who invented the fluoroscope (calcium tungsten screen)

Answer 2

Thomas Edison

Question 3

When did Thomas Edison invent the fluoroscope

Answer 3

1896

Question 4

studied on poor illumination from fluoroscopic screen

Answer 4

William Chamberlain

Question 5

When did William Chamberlain studied on the poor illumination from fluoroscopic screen

Answer 5

1941

Question 6

development of image intensifier tube

Answer 6

1950s

Question 7

measured in units of Lamberts (L) and millilamberts (mL)

Answer 7

Illumination

Question 8

Radiographs are viewed under illumination level to?

Answer 8

10 to 1000 mL

Question 9

Human Vision

Answer 9

• Rods and cones
• Photopic and scotopic vision
• Visual acuity

Question 10

When light appears, the Iris?

Answer 10

The iris contracts

Question 11

When dark, the iris?

Answer 11

dilates

Question 12

primarily used in daylight vision

Answer 12

Cones

Question 13

otherwise called as daylight vision

Answer 13

photopic vision

Question 14

Cones can perceive?

Answer 14

color

Question 15

while cones can perceive color, rods are?

Answer 15

color blind

Question 16

are for night vision

Answer 16

Rods

Question 17

otherwise called as night vision

Answer 17

scotopic vision

Question 18

the ability to perceive fine details

Answer 18

Visual acquity

Question 19

Components of the Fluoroscopic Chain

Answer 19

• Image Intensifier
• Recording System
• Viewing System

Question 20

Electronic vacuum tube that converts the remnant beam to light then to electrons, then back to light, increasing thhe light intensity in the process

Answer 20

Image Intensifier

Question 21

The Image intensifier converts the remnant beam to?

Answer 21

light then back to electrons, the back to light, increasing the light intensity in the process

Question 22

It is a complex electronic device that receives the remnant x-ray beam, converts it into light and increases the light intensity

Answer 22

Image Intensifier

Question 23

The Image Intensifier allows a means to indirectly view the?

Answer 23

Fluoroscopic Image

Question 24

The image intensifier tube is approximately ?

Answer 24

50 cm long

Question 25

A potential difference of about ________ is maitained across the tube between photocathode and the anode so that electrons will be accelerated to the anode

Answer 25

25,000 volts

Question 26

Basic Parts of an Image Intensifier

Answer 26

* Input Phosphor * Photocathode * Accelerating Anode * Output Phosphor * Electrostatic Focusing lenses

Question 27

Converts energy to visible light

Answer 27

Input Phosphor

Question 28

Material used in Input Phosphor

Answer 28

Cesium Iodide (CsI)

Question 29

CsI crystals are tightly packed as

Answer 29

100 to 200 micrometer layer

Question 30

Composed of Cesium and antimony compounds

Answer 30

Photocathode

Question 31

Emission of electrons when stimulated by light from the Photocathode

Answer 31

Photoemission

Question 32

Maintains constant potential of approximately 25 kV

Answer 32

Accelerating Anode

Question 33

Electrons interact to produce light

Answer 33

Output Phosphor

Question 34

Output Phosphor is usually made of?

Answer 34

silver-activated zinc-cadmium sulfide

Question 35

Engineering aspects of maintaining proper electron travel.

Answer 35

Electron Optics

Question 36

Not really lenses, but are negatively charged plates along the length of the II tube.

Answer 36

Electrostatic Focusing Lens

Question 37

The Electrostatic Focusing Lens are located along the?

Answer 37

length of image intensifier tube

Question 38

High energy electrons that interact with the output phosphor each result in substantially more light photon than was necessary to cause their release at the photocathode.

Answer 38

Image Intensifier Tube

Question 39

The length of the Image Intensifier Tube is?

Answer 39

50 cm in length

Question 40

The diameter of the Image Intensifier Tube is approximately ?

Answer 40

15 to 56 cm

Question 41

represents the tube’s conversion efficiency

Answer 41

Flux Gain

Question 42

Flux gain is the ratio of?

Answer 42

number of light photons at the output phosphor to the number of x-rays at the input phosphor number of output light photons ——————————————- number of input x-ray photons

Question 43

is due to the multiplication of the light photons at the output phosphor compared with the x-rays at the input phosphor and the minification from the input phosphor to output phosphor

Answer 43

increased illumination of the image

Question 44

The ratio of Minification Gain is the

Answer 44

the square of the diameter of the input phosphor to the square of the diameter of the output phosphor. input phosphor diameter^2 ————————————— output phosphor diameter^2

Question 45

Minification Gain as a characteristic makes the image brigher because the same number of electrons is being?

Answer 45

concetrated on a smaller surface area

Question 46

In Minification Gain, the output phosphor size is fairly standard at

Answer 46

2.5 or 5 cm

Question 47

In Minification Gain, the Input phosphor size varies from?

Answer 47

10 to 35 cm

Question 48

Brightness gain of most image intensifiers is

Answer 48

5000 to 20,000

Question 49

Is an expression of the ability of an image intensifier tube to convert x-ray energy into light energy and increase the brightness of the image in the process

Answer 49

Brightness Gain

Question 50

Formula of Brightness gain

Answer 50

Brightness Gain = minification gain x flux gain

Question 51

is an expression of the luminance at the output phosphor divided by the input exposure rate

Answer 51

Conversion Factor

Question 52

Recommended by the ICRU to quantify the increase in brightness created by II.

Answer 52

Conversion Factor

Question 53

Exposure Rate and Age of the II

Answer 53

an image intensifier ages, the exposure rate to the patient increases to maintain brightness.