Image Acquisition

Incident x-ray beam produces a ________ within the photostimulable fluorohalides that comprise the active layer of the imaging plate

Latent image

When the _______ luminesce, not all of the energy that is absorbed from the incident x-ray beam is released

Fluorohalides

Even though some of the light is emitted, much of this energy is retained in the phosphors, forming a ___________

Latent image

The latent image formed is what is used to create the _________ for the computer to record and display

Digital image

What is the latent image actually created by?

Energy transfer during photoelectric interactions

Why is it important to process the cassette shortly after exposure?

Latent image loses about 25% of its energy in 8 hours

If exposure field is not recognized accurately, the ______ will contain data outside the exposure firld, widening the histogram resulting in a histogram analysis error followed by a rescaling error

Histogram

Midalignment may cause __________ error which may lead to incoreect exposure indicators

Histogram analysis

Digital radiography allows for a much _______ exposure range

Greater

It is the responsibility of the radiographer to select proper technique; chronic ________ must be avoided

Overexposure

Exposure values that are extracted from the image receptor are subject to a process known as ________ prior to image creation

Quantization

The _______ must quantize, or turn, that continuous stream of electrons into unique values

ADC

What are the two tpes of PSP image receptors?

1. cassette-less system

2. cassette-based system

What type of PSP image receptor is where the plate stay in an upright or table bucky and the technologist never touches it

Cassette-less

What type if PSP image receptor is when the technologist identified the cassette to the computer so that the plate can be inserted and the reader can extract the image data

Cassette-based

The actual extraction of the data in both system is done by using a _____ spot scan or a _____ scan

Flying, line

Image extraction: cassette-less system (flat-panel):

• does not use a cassette

• plate is permanently installed inside the radiographic table/upright Bucky

• a thin film transistor (TFT) and individual detector elements collect the image

• patient is selected from a list in the HIS or RIS

• exposure is made

• image extracted in seconds

Each square in the matrix is a _____

Detector element (DEL)

_______ collect the electrons given off by the amorphous selenium or the amorphous silicon

DELs

DEL size controls the __________ (spatial resolution) for the flat-panel device

Recorded detail

What do DELs do shortly after exposure?

Read the electrons in a sequential pattern that matches their location within the detector matrix

After the electrons are extracted off the TFT array, they are sent to the ______ which sends the digital signal to the computer

ADC

Once the DELs are read, the flat-panel detector automatically ________ and is ready for another exposure

Erases

PSP’s

Rigid sheets with several layers that are designed to record and enhance transmission of the image from a be a, of ionizing radiation

What does the front, white sides of the cassette hold?

Photostimulatble phosphors and the latent image until processing occurs in the image reader

What does the black, black side of the cassette hold?

Two barcode stickers

What is important to note about the barcodes on the cassettes?

Careful when scanning multiple because processing errors occur when a PSP isn’t used for the designated scanned exam

What does the PSP plate reader include?

• read area

• erasure area

• plate or the light collecting system moves

What does a light guide assembly do?

Collects light given off during PSP image extraction