8. Characteristics of diagnostic imaging part 1 Flashcards
Define analog:
Required for viewing, needs to be in analog for us to view it in digital radiography
Define digital, and how pixels give us our image:
-A matrix of pixels represented by numerical values
-After exposure, each number captured by the pixel gives a certain value that will correspond to a certain brightness
Define digital imaging;
An image constructed from numerical data
What are the pixels represented by? What do individual pixels contain?
Represented by a numerical value and contains a series of bits
What are the 2 types of DDR?
- Flat panel direct capture detectors
- Charged coupled devices
What are the two ways that images can be captured in flat panel direct capture detectors?
- Indirect acquisition
- Direct acquisition
Define Indirect acquisition:
2 part process:
- Done through a scintillator
-Converts x-ray photons to light- the amount of light higher for more radiation
-Hits Photodetector and converts light into an electronic signal (binary)
Define direct acquisition:
-Directly convert x-ray photons to an electronic signal (binary signal) through amorphous Selenium
What are the pros of CR?
-Portable (bucky/tabletop, diff room)
-Can adapt to existing radiography equipment
What do the 0 and 1’s represent in binary system?
Either selecting or not selecting something
How is pixel depth (not physical) measured?
-By the number of bits. The more bits associated with the pixel, the more depth
Why do we need depth?
-Without ‘depth’ we would not be able to represent various brightness levels/pixel
How many values can one pixel represent?
-Pixel can only represent one value at a time
What do the bits represent?
-Represent each pixel brightness
How much is 8 bits?
- 8 bits=1 byte
