Lecture 2 - Film and Processing

How are images created in film radiography?

X-rays are exposed a film which reacts to radiation. After chemical processing, areas exposed to more X-rays appear darker, forming an image

How are images created in computed radiography?

X-rays hit an imaging plate with phosphor crystals, which absorb radiation energy. The image on the plate is then converted into a digital image

How are images created in digital radiography?

X-rays directly interact with a digital detector, which immediately converts the radiation into an electronic signal, producing an image

How are images stored in film radiography?

In a dedicated storage area, images degrade over time

How are images stored in computed radiography?

In a PACS system

How are images stored in digital radiography?

In a PACS system

What is exposure latitude?

The range of exposure values (amount of X-ray radiation) that can produce an image of acceptable diagnostic quality

Which type of radiography relies on the use of chemicals?

Film radiography

Which type of radiography relies on the use of a darkroom?

Film radiography

Which type of radiography relies on the use of a phosphor crystal plate?

Computed radiography

Which type of radiography relies on the use of a PACS system for image storage?

Computed and digital radiography

Which type of radiography relies on the use of a digital detector?

Digital radiography

What are the two types of digital radiography?

Direct and indirect

What is the difference between direct and indirect digital radiography?

Indirect digital radiography has a scintillation layer and a photodetector; direct does not

What does a scintillation layer do?

Converts x-ray photons into light photons

What does a photodetector do?

Converts light photons into digital signals

What is automatic processing?

mechanized development of film radiography using an automatic processor, which controls the developer, fixer, wash, and drying steps to produce a diagnostic image quickly

How is beam direction defined?

First by where it enters the body and second by where it exits

What views make up the gold standard for thoracic and abdominal radiographs?

Right lateral, left lateral, and VD/DV