Cassette-based digital imaging is the digital acquisition modality that uses storage phosphor plates to produce projection images. It can be used in standard radiographic rooms just like film/screen.
2.) Imaging Plate (IP)
3.) Computed Radiography Reader
4.) Optical Components
5.) Computer Control
What are the basic components of a CR system?
It consists of a durable, lightweight plastic material. A light-proof container that protects an imaging plate from light and handling and is backed by a thin sheet of aluminum that absorbs x-rays.
It is housed in a cassette. The material must have the ability to store and release the image information in a usable form.
Barium Fluorohalide Bromides and Iodides with Europium Activators
The most common phosphor with characteristics favorable for CR is?
Computed Radiography Reader
The cassette is fed into this that removes the imaging plate and scans it with a laser to release the stored electrons.
Light Collecting Optics
Emitted light from the IP, is channeled into a funnel like fiber optic collection assembly and is directed at the photodetector, photomultiplier tube (PMT) photodiode (PD) or charge-coupled device (CCD).
It receives light from the fiber optic collection assembly, and transmits a time-varying analog signal to a computer system.
1.) Protective Layer
2.) Phosphor or Active Layer
3.) Reflective Layer
4.) Conductive Layer
5.) Color Layer
6.) Support Layer
7.) Conductor Layer
8.) Light Shield Layer
9.) Backing Layer
What are the layers of the imaging plate?
Phosphor or Active Layer
Holds the Photostimulable phosphor (PSP), which is the active component in the plate.
It sends light in a forward direction when released in the cassette reader. This layer may be black to reduce the spread of stimulating light and the escape of emitted light.
It is located between the active and support layers of the IP that absorbs the stimulating light but reflects emitted light.
A semi-rigid material that gives the imaging sheet some strength and a base on which to coat the other layers.
It grounds the plate to eliminate electrostatic problems and absorb light to increase sharpness.
Light Shield Layer
It prevents light from erasing data on the imaging plate or leaking through the backing, decreasing the spatial resolution.
It is defined as light produced by a phosphor (active layer) when struck by light or x-ray photons. It occurs following x-ray exposure. However, it also occurs some time later when exposed to a different light source (laser beam).
Scanning of the IP by a laser occurs in a ____ as the plate is fed through the processor.
It is performed to optimize the appearance of the image for purpose of better detecting pathology.
In order to evaluate the exposure for CR image, most manufacturers have an ______ that provides information on the average amount of radiation used for an image.
_____ uses a sensitive number (S number) that is related to the amount of amplification required by the PM tube to adjust the digital image.
______ CR indicator system is called the exposure index, which is directly proportional to the radiation striking the IP.