Chapter 5: Thin-film transistor

Photoconductors are materials that

absorb x-rays and produce electrical charges

Scintillators are phosphors that

produce light when absorbing x-rays

A device that includes a photosensitive array and small pixels that convert light into electrical charges is known as a BLANK transistor

thin-film

A device that acts like a switch to send electrical charges to the image processor in a direct conversion flat-panel detector is known as a BLANK transistor

field-effect

In a flat-panel detector, specialized silicon integrated circuits control

line scanning sequence

Amplifiers perform all of the following functions except

noise cancelling

Which of the following is used as a photoconductor?

a-Se

Which of the following is not considered a scintillator?

a-Se

Flat-panel detectors that use indirect conversion technology convert

x-rays to visible light

Indirect conversion in flat-panel detectors is a BLANK -step process

two

The type of flat-panel detectors that uses thin films of silicon integrated with arrays of photodiodes is known as a(n)

Amorphous silicon detector

CsI detectors use

thin crystalline needles

In CsI detectors

there is very little light spread

A Gd2O2S scintillator is known as what type of phosphor?

Both Turbid and Unstructured

Detector performance is measured with all of the following except

contrast

Defective, or dead, pixels can result from all of the following except

software programs

Manufacturers make efforts to maintain a standard of less than BLANK defective pixels

0.1-0.2%

Possible causes of image lag include all except

underexposure

All of the following statements are true except

Dead pixels at the edge of the detector are easily identified

Which of the following can be down to decrease the chance of having image lag occur in the next image?

Increase the amount of time between exposures