Digital Radiography Flashcards
What solid state detector (sensor) does VCU use in clinic?
Charge couple devices
What solid state detector (sensor) is used for Panos?
Flate panel detector
What does analog image/films color look like?
Continuous shades of grey, no pixels
What does digital image color look like?
Discrete shades of grey, pixels
What is a pixel?
A discrete unit of information
How are electronic elements of a digital sensor arranged?
In a regular grid of rows and columns
What are the steps of a digital sensor?
- X ray exposure
- Sensor
- Electronic charge is produced at each pixel
- Transmit to the computer
- Analog to digital conversion
Computer assigns a number and eventually a shade of grey
What are the lower numbers of pixel values representative of?
White/lighter shades
What are the higher numbers of pixel values representative of?
Black/darker shades
Do we use wired or wireless sensors in clinic?
Wired sensors
What does the intensifying screen do in a sensor?
Converts x-rays into light photons
What is the order of the parts of a sensor that X-rays hit, from first to last?
- X-rays
- Frontal housing
- Scintilator screen
- Fiber optic face plate/ optical lense
- CCD
- Electronic substrate
- Back housing
What do the thin walls of silicon do in a sensor?
Crystals are in the pixel matrix
What happens on the sensor during x-ray exposure?
Covalent bonds between silicon atoms are broken, electron hole pairs
The number of electrons released is proportional to the…
X ray exposure
