click below
click below
Normal Size Small Size show me how
Rad Pro week 4
Rad Protection week 4 reveiw
Question | Answer |
---|---|
During Tomo the x-ray tube and IR move around an imaginary pivot point called the ___. | Fulcrum |
The tomo angle determines the | section thickness |
As the tomo angle ____ the tomo section. | increases, becomes thinner |
The height of the fulcrum determines the | Level of the object plane |
Each sweep of the source-detector around the body during CT is called a ____ | Rotation |
The principal drawback of the 1st gen CR scanners was the | Long scanning time |
The reduction in ___ was the principal advantage of the 2nd gen CT scanners | Scanning time |
The 3rd gen of CT scanners allowed for further reduction in | Scanning time and scattered radiation |
The ___ gen of CT was the 1st to have the fan-beam transect the entire PT at all times | 3rd |
What is the principal disadvantage of 3rd gen CT | Ring artifacts |
The new development in the 4th gen CT is the | Stationary detector array |
The concentration of scintillation detectors affects the ___ of the CR image | Spatial resolution |
The PT. dose in CT is determined by the ___ collimator | prepatient |
The time from end of CT imaging to image appearance is called ___ time | reconstruction |
Each pixel of info in the CT image contains numerical info in ___ units | Hunsfeild |
CT imaging has excellent ___ because of one narrow beam collimation | Contrast resolution |
The CT scanner must be calibrated so that ___ is at CT number zero | Water |
What is the one design featrue that makes spiral CT possible | Slip rings |
The __ in the spiral CT gantry usually have to be replaced annually | Brushes |
The volume of contrast is ___ and the images are ____ with spiral CT angiography | reduced, better |