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Final exam RA222
Final Exam RA222
Question | Answer |
---|---|
Minification Gain | Diameter of input phosphor/Diameter of output phosphor; Squared |
How does multifield image intensification work? | Reduces the field of view thereby magnifying the image The electron focal spot moves further from the output phosphor. |
Function of the television monitor | Convert light image of fluoroscopy tube to electrical signals. |
Conversion factor | Output phosphor illumination/input exposure rate |
Vignetting | Decrease in image brightness and sharpness. Fuzzy on images at edges. |
Flux Gain | Number of output light photons/Number of input x-ray photons |
Brightness gain | Minification gain x Flux gain |
Ascities | Accumulation of fluid in abdomen |
Pulmonary embolism | Blood clot that becomes lodged in the lungs |
Pulmonary edema | Swelling and fluid in air sacs and bronchioles |
Emphysema | Loss of elasticity of lung tissue. Hyperinflation of air sacs. Destruction of alveolar walls |
Pleural Effusion | Fluid in pleural space |
Tabletop exposure fluoroscopic | Max 10 R/min |
Cardinal rules of radiation protection | Time--As short as possible. (Time doubled = Exposure doubled. Distance--Large as possible between source of radiation and patient Shielding--Shield between radiation source and Patient. |
MRI Scanner | Inveted by Dandian. first used in 1974 for rat tumor |
Matrix | Rows and columns of pixels |
Fluoroscopy | Examining moving internal structures and fluids. (Dynamic studies) |
Dynamic | Motion; fluoroscopic images "moving" |
Quantum mottle | Grainy appearance. Caused by too few electrons. |
NMR | Nuclear magnetic resonance. Magnetic fields and radiowaves cause atoms to give off radio signals. |
HIS/RIS | Hospital Information Systems/Radiology Information Systems. Provides worklists and reports. No manual entry of data |
ALARA | As Low As Reasonably Achieveable |
Path of x-ray | Patient, Glass envelope, Input Phosphor, Photocathode, Electrostatic Lenses, Anode, Output phosphor |
Inverse square law | The intensity of radiation is inversely proportional to the distance squared. If distance is doubled then patient exposure is reduced 4 times |
Quality Assurance (QA) | Overall patient care in radiology department |
Quality Control (QC) | Technical elements that affect image quality |
Radiation Control for Health and Safety | 1968 |
X-ray equipment standards developed in | 1974 |
Consumer patient radiation health and safety act | 1981 |
Recommendation for QA programs published | 1978-1979 |
Filtration (Beam quality) | Most important patient protection. 2.5 mm of Al. Single phase 70 kVp 1.6. 3-phase/high frequency 70 kVp 2.0 |
Collimation-Beam alignment | distance & Alignment not exceed 2% of SID. Centering 1% of SID "Coin test" |
Focal spot size | Determines spatial resolution. Test with pinhole camera, star pattern, or slit camera (most effective) |
Linearity | Produce same mAs no matter what mA and time used. Within 10% |
Reproducibility | Produce same technique (kVp, mA, time) Produce same density and contrast. Reproducible within 5%. Dosimeter used for testing. |
Back up timer | Terminates exposure at 6 seconds or 600 mAs |
Illuminators (View Boxes) | Variation not to exceed 10% |
Film screen contact | Test with wire mesh pattern. Check for contact or blurring |
Aneurysm | A sac formed by local enlargement of a weakened arterial wall |
Angiography | Radiographic demonstration of blood vessels after the introduction of contrast medium |
Arteriography | Radiographic examination of arteries after the injection of a radiopaque contrast medium. |
Atherosclerosis | A pathological condition of thickening and hardening of arterial walls leading to a loss of elasticity |
Biplane imaging | Two x-ray exposures planes 90 degrees from another, usually frontal and lateral |
Catherization | Introduction of a catheter into the body cavity, organ, or vessel to inject or remove fluid. In radiology the injection of contrast media for diagnosis. |
Claudication | Cramping of the leg muscles after physical exertion because of a chronically inadequate blood supply |
Digital Subtration Angiography DSA | Use of digitally recorded x-ray images to produce subtraction images of vessels. |
Hematoma | Collection of extravasted blood in an organ or a tissue space |
Occlusion | Obstruction or closure of a vessel, such as a coronary vessel, as a result of foreign material, thrombus, or spasm. |
Percutaneous | Introduced through the skin |
Percutaneous Transluminal Angioplasty | Surgical correction of a vessel from within the vessel using catheter technology. |
Seldinger Technique | Seldinger developed a method for arterial access using a catheter. The ideal puncture is in the femoral artery. An 18 gauge needle containing an inner cannula pierces through the artery. The needle is withdrawn slowly until there is blood flow. The ne |
Stenosis | Narrowing or constriction of a vessel, an orifice, or other type of passageway |
Venography | Radiographic study of veins after the injection of radiopaque contrast medium |
Tomography | Radiographic technique that shows a single plane of tissue by blurring images of structures above and below the plane of interest |
Fulcrum | Point of axis of rotation for a tomographic motion |
Exposure Angle | Degree of arc angulation described by the movement of the x-ray tube and cassette during a tomographic motion |
Curie | Standard of measurement for radioactive decay; based on the disintegration of 1 gram of radium at 3.731010 disintegrations per second |
Gamma Cameras | Device that uses the emission of light from a crystal struck by gamma rays to produce an image of the distribution of radioactive material in a body organ |
Geiger Counter | Used to detect the amount of radiation present |
Half-life | Term used to describe the amount of time that a physical quantity has decreased to half its original value |
Scintillate | To emit photons |
Tracer | A radioactive isotope that allows a biological process to be seen. |
X-ray dyes vs. MRI dyes | X-ray uses radiation, blocks x-ray from passing thru area exposed, and has a reaction risk. MRI uses no radiation, alters magnetic field in tissue examined, and risk of reaction is slim to none. |
Aphasis | Abnormalties of function related to speech |
Agonal breathing | labored breathing, gasping, shallow slow, irregular inspirations followed by irregular pauses. |
Positioning coils | amplify signal, focus magnetic field on area of interest |
Bore | Opening |
Resistive magnet | Electrify to create magnetic field. Once power turned off magnetic field is gone |
Permanent magnet | Magnetic field is always present |
Super conducting | Similar to resistive magnet. Magnet wrapped with coil of wire. Wire is continually cooled |
MRI | Uses magnetic fields and radiowaves/frequencies to create images |
MRI Scanner Invented in | 1970, but first used in 1974 to image a rat tumor |
Repeat analysis | Purpose to catch any equipment malfunctioning that may be occuring at a slow rate |
Data Collection | Purpose to check for any changes or fluctuation from required range |