Chapter 4 - Cassette-Based Equipment

Radiographic

General x-ray procedures as distinct from other digital modalities

CR cassette

It consists of a durable, lightweight plastic material.

Imaging plate

In CR, the radiographic image is recorded on a thin sheet of plastic known as…?

Protective layer

This is a very thin, tough, clear plastic that protects the phosphor layer.

Phosphor or active layer

This is a layer of photostimulable phosphor that “traps” electrons during exposure. It is usually made of phosphors from the barium fluorohalide family.

Reflective layer

This is a layer that sends light in a forward direction when released in the cassette reader.

Conductive layer

This is a layer of material that absorbs and reduces static electricity.

Color layer

Newer plates may contain this. It's located between the active layer and the support, that absorbs the stimulating light but reflects emitted light.

Support layer

This is a semirigid material that gives the imaging sheet some strength.

Backing layer

This is a soft polymer that protects the back of the cassette.

1. Protective layer

2. Phospor layer

3. Light reflective layer

4. Conductive layer

5. Support layer

6. Light shielding layer

7. Backing layer —> Bar code label

Construction of Imaging Plate (in order):

Barcode label

It’s on the cassette that allows the technologist to match the image information with the patient-identifying barcode on the examination request

Phosphor center

When this interaction stimulates, or gives energy to, electrons in the crystals, allowing them enter the conductive layer, where they are trapped in an area of the crystal known as…?

Reader

It removes the imaging plate and scans it with a laser to release the stored electrons.

light amplification of stimulated emission of radiation

Other word for laser?

Laser

A device that creates and amplifies a narrow, intense beam of coherent light.

Translation

What do you call the plate movement through the scanner that moves in a parallel manner at a certain rate through the reader?

Photomultiplier

It amplifies the light and sends it to a digitizer. It detects the lines of light intensity information that the scan process produces?

Mirrors

They are used to ensure that the beam is positioned consistently.

Analog

Refers to a device or system that represents changing values as continuously variable physical quantities.

Watch

What’s a typical analog device?

Bit depth

Each pixel contains bits of information, and the number of bits per pixel that define the shade of each pixel is known as…?

Spatial resolution

It’s the amount of detail present in any image.

Speed

It is determined by the size and layers of crystals in the film and screen.

Photostimulable luminescence (PSL)

CR system “speeds” are a reflection of the amount of…?

1. protective

2. phosphor

3. reflective

4. conductive

5. color

6. support

7. backing layers

The imaging plate is multilayered with protective what?

Barcodes

These are used to identify the cassette or imaging plate and examination request to link the imaging plate with the patient examination.

Barium fluorohalide crystals

It releases light energy in the imaging plate, which is then stored in the conductive layer.

Blue light

The imaging plate reader uses a laser to scan the imaging plate, releasing the energy stored in the conductive layer as…?

Digitizer

Assigns a numerical value to each pixel in a matrix according to the brightness of the light and its position.

QC station

It’s where images are sent and analyzed and sent to PACS for long-term storage.

By exposing them to bright light such as fluorescent light.

How are imaging plates erased?