click below
click below
Normal Size Small Size show me how
adv img digital
advanced imaging digital 1 of 3
Question | Answer |
---|---|
CCD | charged couple device, converts light into an electronic signal. |
What are the advantages of digital fluoroscopy? | post processing enhancement, speed of images |
Where is the CCD located? | mounted to the output phosphor of the II |
Can a CCD be connected to other devices? | no |
What are the two most common TV tubes? | plumicon and vidicon |
How is spatial resolution measured? | line pair/mm |
SNR | signal to noise ratio |
DQE | conversion of x-rays to light |
Conventional TV camera tubes have an SNR of: | 200:1 |
DF has an SNR of: | 1000:1 |
How does DF work? | an electronic signal is converted to digital and sent to the computer where the output signal is sent through the ADC to the main memory, then through the DAC to the monitor. |
How is pixel brightness determined? | pixel brightness is inversely proportional to the radiation incident on it. |
Hounsfeld unit | in CT, the numerical value of each pixel |
Does better spatial resolution have more or less pixels? | more |
What is the difference between a pixel and a voxel? | a voxel is 3D ( it has slice thickness) |
Bit depth/dynamic range | the number of shades of gray each pixel can display (numerical range of densities) |
How many bits are in a byte? | 8 |
In digital, what does mAs control? | the EI number or exposure number (NOT density) |