Chapter 22: Flat panel detectors

Flat pabel detector:
No _________ required
1995
Direct detectors use _________
--- coverts x-rays into an electrical signal
Indirect detectors use __________
--- converts x-rays to light

cassette, photoconductor, scintillator

Indirect conversion detectors:
2 step process uses a _________ and a _____________

scintillator and photodetector

Indirect conversion detectors: Includes either a ___________OR
Amorphous ________ with a TFT (Thin film transistor)

CCD, silicon

Dorect DR:
Capable of directly converted x-ray photons to ___________ _________
Amorphous _________ and a TFT

electrical signal, selenium

Indirect detectors scintillators are made of one of two materials, lost the two options.

cedium-iodide or gadolinium oxysilfidr

Indirect detectors flat panel is made of an amorphous __________

silicon

The flat panel detector on indirect detectors works as a photodiode to capture _______
Converts light to electrical charges that are then deposited on the _______

light, TFT

_________ __________ ________ collects electrical charges (produced by either a-Se or a-Si) as a matrix of pixel-size Detector Elements(DEL)

Flat panel TFTs

TFTs have a switch for each ______ in a row which is activated. The signal is sent to ______ then the computer

DEL, ADC

_______ _________ refers to the sensing area compared to the non-sensing area (Pixel detector sensing area related to the DEL)

fill factor

True or false: Detector electronics that are not sensitive to the charge do not take up a certain amount of space

false, they do take up space

A DEL is made of what three things?

sensing area, TFT, storage capacitor

As the active area increases (the higher the fill factor) = spatial resolution ________

increases

Smaller DEL size= ________ PP= _______ resolution

smaller, better

Does a CCD photodetector have a scintillator?

yes

CCD photodetector requires optical coupling by _______ or ______ optics to connect the light to the CCD sensor

lenses or fiber

CCD photodetectors turns visible light into an electric charge and __________ it

stores

True or false: with CCD photodetectors, the stored charge is released line by line to the ADC. making it a digital signal that can be sent to the computer

True

________ is the older version of CCD'S

CMOS

With Direct DR:
Amorphous ________ & TFT
Directly converts x-rays into _________ signal
Prior to the exposure, a high _______ charge is applied from the top surface of the selenium layer
X-ray photons come in- Ionize ________ atoms
Electrons collected at _________
Electrons received by _______, sent to ______, and finally sends the signal to the ________

selenium, digital, voltage, selenium, electrodes, TFT, ADC, computer

with imaging processing and display: Processing principles are similar to those used in _____(DR/CR)
Entire ______ is not read as it is with CR
If the flat panel has some bad detector elements, it can be corrected by system ___________

CR, IR, calibrations

With FDP:
DR panels typically require a communication with x-ray _________
Generator is what sends high ______ charge to the TFT
Earlier versions- electrical connection through ________
Newer version- _________technology
--- generator specific

generator, voltage, wires, wireless

Generator-specific interfacing is being replaced with _____ panels that can be used with any x-ray machine manufacture

DR

auto-detection Works by sensing the presence of radiation during the first ____-___millisecond of exposure.
A small charge is placed on the TFT by an on-board ______ so TFT can capture the electrons
Referred to as ________ panel since the presence of irradiation triggers the collection of electron which then creates an electronic signal

1-2, battery, trigger

DR panels precautions include:
DR panel ________(Senses force encountered)
________ invasion(encased with bag to prevent)
_______ restrictions

autopsy, fluid, weight