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CT Review 1
History/Development
| Question | Answer |
|---|---|
| Name the 2 inventors of CT. | Sir Godfrey Hounsfield and Allan Cormack |
| The name Hounsfield is now used to describe what? | brightness/contrast of tissues in CT images |
| CT is _______ dimension. | 3 |
| Conventional Radiography is _____ dimension. | 2 |
| Third generation is also referred to as ____-____ motion. | rotate-rotate |
| Helical/slip ring is what generation scanner? | 3rd |
| What is pitch? | determines how fast the body is moved thru the scanner and how much the xray beam is spread over the body. |
| What was the first scanner used to examine? | head |
| A ct number is also referred to as? | Hounsfield number |
| What planes do CT images use? | axial, sagittal, coronal |
| What is the slip ring? | the rotating assembly used to enable the passage of electrical signal during continuous rotation of the helical ct scanner |
| What is helical/spiral ct? | the type of ct acquisition whereby the xray tube and pt continuously move during scanning, yielding a raw data set in the form of a helix |
| What is the 5th generation scanner called? | electron beam |
| what is the first image taken with a ct machine? | scout image |
| higher pitch= | shorten scan time |
| what are some advantages of helical? | pt can hold breath, less motion, better use of contrast, faster study |
| What is raw data? | the transmission measurements obtained by the detectors used to mathematically reconstruct the ct image |
| What is single slice CT? | a ct system with a single row of detectors capable of acquiring only one image section for each gantry rotation |
| What is multi-slice ct? | has multiple rows of detectors, increased speed, good for angiography, can obtain more than one section for each gantry rotation. |
| How many times higher are the differences between tissue with CT compared to Xray? | at least 10x higher |