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adv img CT 2
advanced imaging - CT set 2
Question | Answer |
---|---|
What percentage of radiology exams are CT? | 12% of diagnostics |
What percentage of the US population’s radiation dose is due to CT? | 45% |
Axial CT alternate name | conventional tomography |
CT alternate name | trans-axial |
Who invented CT and when? | Godfrey Houndsfeld in 1967 |
A voxel is also called what? | a houndsfeld unit |
What was the first CT unit installed? Where? | England, 1969 |
What type of CT was the first one and who made it? | A head unit by EMI |
Major downfall of first generation CT scanners? | long scan time |
Major downfall of third generation CT scanners: | ring artifact |
What is significant about the second generation CT scanners? | they used a fan-shaped beam |
What is significant about the fourth generation CT scanners? | detectors were stationary |
Major downfall of fourth generation CT scanners? | pt. dose |
What are the advantages of the 5th generation CT scanner? | faster, real time |
Alternate name for 5th generation CT scanners | electron beam tomography |
What is significant about 6th generation CT scanners? | they’re helical or “spiral” allowing continuous spin of the tube |
What is the major advantage of 6th generation CT scanners? | abdomen scan time is 30-45s. |
What determines section thickness for the 6th gen CT scanner? | detector |
What do “slices” mean? | number of images produced with one tube rotation |
What is found in the gantry? | x-ray tube, detector array, high voltage generator, couch and mechanical supports |