| 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 |
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