L5 - DR FLUORO WITH FLAT PANEL DETECTOR

describe steps of digital fluoror using a flat panel detector

. xray > patient > grid > direct or indirect flat panel detector > analog signal > ADC > digital signal > computer > DAC > image

what is a flat panel image receptor made out of

cesium iodide or amorphous silicon pixel detectors

what does FPIR stand for

flat panel image receptor

what is a direct detection also known as

photoconductors

what does a photoconductor do

xrays are converted into a electrical signal

what is a photoconductive amterial

amorphous selenium

what is on top of a TFT array usually

amorphous selenium

what does amorphous selenium do?

convert xrays to electrons

what chemical is used in direct detection

amorphous selenium

what does a indirect detection system have?

scintillation layer

what does a scintillation layer do

converts xrays to lights

what chemical in a indirect detection system collects light

amorphous silicon

what does the amorphous silicon do in indirect detection systems

collects light from the scintillation layer and converts it to electrons

what are the typical matrix sizes

1024 × 1024 or 2048 × 2048

is a flat panel bigger or smaller than II

smaller

what is the function of a flat panel detector

read out complex electronics

what are the frames per sec on a FPD

15-30

what should be the initalization, interrogation, and read out time be completed in for 1 image

33 ms

what is teh read out rate in FPD

15-30ms

why should we choose FPIR over II?

• distortion free

• constant image quality

• high DQE

• high dynamic range

• unaffected by magnetic fields

• ]rectangular image area coupled to similar image monitor

what is last image hold

last frane hold circuit is a fast ADC converter that converts the video signal to a visible iamge. important for patient dose

what a typical monitor resolution

525

higher resolution monitor

875-1024

if there is 525 lines how many lines approx lp/mm

1-2 lp/mm

if there is 1024 lines how many lines approx lp/mm

2.5-5 lp/mm

how to calculate bandpass

number of times / sex that the electron beam can be modulated

higher band pass = ?

higher resolution