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Chapter 40 & 41
Principles of Radiographic Imaging (Carlton)
| Question | Answer |
|---|---|
| T or F Brightness gain increases with use | False |
| Full intercept position | the only time when an exposure can be made in fluoroscopy |
| T or F There is a direct relationship between distance from the fulcrum and blur | True |
| Quantum Mottle | grainy appearance caused by too little radiation |
| T or F Video monitors emit low energy x-rays | True |
| Automatic brightness control response time | slow |
| T or F Fluoro tubes routinely use high mA stations | Fasle - longer periods of time with low mA |
| Complex tomo movements require this | Counter-rotation of the grid |
| Minimum SSD for stationary fluoro | 15 inches |
| T or F The more blurring the more density | False - decreased density |
| In linear tomo, structures parallel to the motion do this | streak |
| Main use of tomo's | localize objects without superimposition |
| Section thickness decreases with this | increased tomo amplitude |
| These commonly occur during circular tomo | phantoms |
| In a fixed fluoroscopy unit SOD cannot be less than this | 15 inches |
| Flux gain | measurement of the increase in photons caused by conversion efficiency of the output screen |
| Minimum for SSD for moblie fluoro | 12 inches |
| The relationship of tomo amplitude and section thickness | Inverse |
| The mounting for a fluoro tube and image receptor | C-arm |
| During intensification, the beam exits the patient and hits this... | input screen of the intensifier |
| Monitors the current between the cathode and anode of the intensifier to maintain density and contrast | Automatic brightness control systems |
| It is a dynamic and diagnostic study | fluoroscopy |
| Relationship of the image receptor to blur width | direct relationship |
| This supports the intensifier, the power drive controls, and the spot film selector | Carriage |
| Modality used for heart studies, surgical procedures, intestinal studies, and GI tract studies | Fluoroscopy |
| Adjustments in techniques are made this way because time settings are fixed and cause limitations | by varying kVp |
| The distortion from the input screen is controlled by this | shape of the screen |
| The shape of the input screen | concave |
| Struck by the primary beam after exiting the patient in fluoroscopy | input screen |
| Edge distortion in image intensification tubes | vignetting |
| most common fluoro viewing system | real-time video |
| The input screen emits this | light photons |
| The input screen absorbs this | x-ray photons |
| Composed of photoemissive metals | photocathode |
| Photoemissive materials emit this | Electrons |
| Standard spot film cassette | 9x9 cassette |
| Absorbed by the photocathode | light photons |
| The photocathode emits | electrons |
| These are actually charged electrodes | electrostatic lenses |
| Common solution for quantum mottle | Increase mA |
| Standard number of digital fluoro pixels | 200-300 micrometers |
| The output screen absorbs this | electrons |
| The output screen emits this | light photons |
| A measure of the increase in image intensity, determined by the minification gain, and determined by the flux gain | total brightness gain |
| Where to put body part being imaged by tomography | at the fulcrum |
| They are focused and accelerated by the electrostatic lenses | electrons |
| The primary brightness gain occurs because of this... | the acceleration and focusing of the electron beam |
| The greater the voltage supplied to the electrostatic lenses the greater this... | acceleration and the closer the focal point |
| Varies fluoroscopic resolution | minification gain, electrostatic focal point, and input & output screen diameter |
| T or F Body part imafed at the fulcrum is sharp in details | True |
| T or F The greater the distance from the fulcrum, the greater the blurring | True |