Final Exam RA222

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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  


   

 
 

 
 

 

 
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