Digital Systems Flashcards
Computer file type for diagnostic imaging
DICOM
Digital imaging and communications in medicine
What is stored in Metadata files of dicom?
Manufacturer of device Image date and time Patient info Acquisition parameters Referall practitioner Operator identifiers Others
T or F
DICOM standard is voluntary for equipment
True
What is the basis for digital files?
Pixels in a matrix
What does the size of pixels relate to?
Spatial resolution
What is bit depth?
Number of digits able to be assigned to a pixel
Only 0 and 1 are used (0=black and 1=white)
If there are more digits assignable there are more shades of gray
Difference between CR and DDR?
In CR a recording device (cassette) records the distribution of x-rays
DDR don’t have cassette and are rigid
What is contained in a CR plate?
Photostimulable phosphor
NO intensifying screens like film
What reads the PSP in CR
Laser that converts temporary image to electronic signal
How is a CR cassette cleared?
Bright white light
What are the three types of DDR?
Indirect flat-panel detectors
Direct flat-panel detectors
Charged-coupled device
What are indirect flat panel detectors?
Photodiode intensifying screen that converts visible light to electronic
What is range of bit depth
10-16
What bit depth do indirect flat panel have
14
Howard simultaneous shades of grey can human eye detect?
50-100
How does direct flat panel detector work
X-rays strike photoconductor (amorphous selenium) which transforms to Acharya and read directly by a thin film transistor array and converted digitally
Difference between indirect and direct flat panel
Direct does NOT use light as a middle man
Bit depth of direct flat screen
14
Same as indirect
Is there light diffusion with indirect flat panel detectors?
Yes, but it’s not clinically significant
