Physics Chapter 22 Intensifying Screen

Front 1

Converts xray photons to light, single or double, within a film cassette

Back 1

Intensifying screen

Front 2

99% of the diagnostic image is created by the intensifying screen light emission

Back 2

Latent image

Front 3

Less than __% of the xrays landing directly on the film will interact with it

Back 3

1

Front 4

About __ %of the xrays landing on the screens produce light

Back 4

30

Front 5

In the screens what receives the x radiation

Back 5

Phosphor--->emit light---->expose film

Front 6

Varies depending on desired resolution and response time (speed)

Back 6

Layer thickness

Front 7

High atomic # increases efficiency of xray absorption, higher light photon emission

Back 7

Photon characteristics

Front 8

Must emit the same wavelength energy (color) as what the film is sensitive to

Back 8

Spectral emission

Front 9

Heat, humidity, any other radiant energy, prevent film fog

Back 9

Insensitive to environment

Front 10

Must stop emitting light when xray exposure stops

Back 10

No afterglow

Front 11

Must be uniformly radiolucent, chemically inert, flexible

Back 11

Base of intensifying screen

Front 12

Between base and phosphor layer

Back 12

Reflective layer

Front 13

Sends photons back towards the film

Back 13

Reflective layer (greater the # of photons reaching film, less amount of xray is needed)

Front 14

Reduces light scatter and protects resolution, absorbs light photons of longer wavelengths

Back 14

Dye within reflective layer

Front 15

Ability to emit light in response to a stimulant, emit light when exposed to xray this is called

Back 15

Luminescence

Front 16

What happens when crystal is stimulated

Back 16

Outer shell e- receive energy and elevate, as they drop back they release excess energy in the form of light photons

Front 17

The light emissions are of a specific __ representing a particular __

Back 17

wavelength, color

Front 18

Is fluorescence good or bad luminescence

Back 18

Good-_light emission only during stimulation

Front 19

Is phosphorescence good or bad luminescence

Back 19

Bad- continued light emission post stimulation (aka screen last or after glow, leads to over exposure)

Front 20

How long is screen life

Back 20

5-7 years

Front 21

What are the 2 types of phosphor crystals

Back 21

Calcium tungstate, rare earth

Front 22

What is the conversion efficiency of calcium tungstate

Back 22

5%

Front 23

What is the conversion efficiency of rare earth

Back 23

15-20%

Front 24

Smaller crystals, thinner layer more__ but higher patient __

Back 24

Resolution or detail, dose

Front 25

How quickly screens can expose the film is called

Back 25

Speed (determined how much xray is needed

Front 26

Faster screens is __ technique __ patient dose

Back 26

Less, less

Front 27

Larger the crystals, __ the exposure, __ the screen, __ the dose (good) ,__ resolution (bad)

Back 27

Quicker, faster, lower, less

Front 28

Thicker the phosphor layer,__ the screen,__ the dose,__ detail/resolution

Back 28

faster, lower, less

Front 29

__ the #, __ the screen, __ the resolution

Back 29

Higher, faster, lower

Front 30

Relative speed # detail screens

Back 30

100 or less

Front 31

Regular speed

Back 31

100-400

Front 32

High speed

Back 32

up to 1200