RT101 - IMAGING SCIENCE AND INFORMATICS

Cassette

What is the rigid holder that contains the film and intensifying screens?

Compression device/ Radiolucent plastic foam

What device helps maintain close contact between the screen and the film?

Heavy metal

What is the back cover of the cassette usually made of?

To convert x-ray energy into visible light

What is the purpose of the intensifying screen?

Visible light

Film is more sensitive to which type of energy: x-ray or light?

90%-99%

What percentage of energy exposure to the film comes from light?

Protective coating, phosphor layer, reflective layer, base

What are the four main layers of the intensifying screen?

Phosphor layer

What is the active layer in the intensifying screen?

Gadolinium, lanthanum, yttrium

What elements are commonly used as phosphor materials?

To prevent abrasion and damage

What is the role of the protective coating?

Reflect light photons back toward the film

What is the main job of the reflective layer?

Magnesium oxide, titanium dioxide

What materials are used in the reflective layer?

Polyester

What material is commonly used for the base layer?

Base

What is the layer that provides mechanical support in the screen?

They move to an excited state and return, releasing visible light.

What happens to electrons during luminescence?

Photoelectric effect

What effect occurs in the back cover due to its high atomic number material?

Detective Quantum Efficiency (DQE)

What efficiency refers to how much x-ray is absorbed in the phosphor layer?

X-ray Conversion Efficiency (CE)

What efficiency refers to how much light is emitted per x-ray absorption?

Fewer light photons reach the film; lower efficiency

What happens if an intensifying screen lacks a reflective layer?

1 mm

How thick is the base layer approximately?

Heat, humidity, and other environmental conditions

What environmental conditions should phosphors resist?

Thousands of visible light photons per x-ray absorbed

What does the luminescence process emit?

Lower patient dose, less tube stress, and reduced shielding

Why are rare earth screens beneficial in radiography?

Front cover

What part of the cassette is made of low atomic number material?