DR flat panel detectors

list the two types of flat panel detectors

direct and indirect capture

name the scintillator commonly used with direct capture

amorphous selenium

name the scintillator commonly used with indirect capture

amorphous silicon

this device can be used instead of a CCD, but image quality is not as good 

CMOS

describe the advantage of columnar shaped crystals

improves resolution

an array of hardware pixels is

digital image receptor

direct flat panel detectors are constructed using a

thin film transistor

what is the function of a TFT switch

releases signals to be read out 

what is the function of a capacitor within the DEL

stores charge

what device converts the signal released from the DEL to a digital signal

ADC

the amount of the DEL that is available to convert the incoming signal (xray or light) to an electronic signal is called the

fill factor

ADC function

sends electrical signals to computer

amplifier function

amplifies signal to ADC

TFT function

converts xray to digital signal readout 

capacitor function

stores charge

photoconductor function

absorbs xrays and emits electrical charge

what is a DEL

data element

the “bucket brigade” system refers the signal readout from the device

CCD

scintillator definiton

phosphors that absorb xrays and emit light

photoconductor definition

absorbs xray and emits light electrical charge and converts light to electrical signals

list the components of a direct capture system

TFT, photoconductor, capacitor

_____ ____ occurs when the detector doesn’t clear the signal from the previous image

image lag