In each blank, try to type in the
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If your not sure what answer should be entered, press the space bar and the next missing letter will be displayed. When you are all done, you should look back over all your answers and review the ones in red. These ones in red are the ones which you needed help on. Question: of radiation risksAnswer: , long-term, cumulative Question: Biologic Effects of Ionizing Radiation (BEIR) VII risk model for exposure to low-level radiationAnswer: approx. 1 in 100 people are likely to develop solid cancer or leukemia from an exposure of 100 mSv above background Question: Important for patient Answer: Good communication and assurance programs Question: Beam Answer: single most important factor in keeping patient dose to a minumum, only of diagnostic interest should be iradiated -reduces pt dose, reduces production of scattered radiation, improves quality of image Question: Beam restrictor Answer: aperture diaphragm, cone/cylinder, Question: CollimatorAnswer: most efficient, attached to tube head, first set of shutters placed close to x-ray tube port window to control amt of image degrading "off-focus" leaving tube, lead shutters (two adjustable)for length and width Question: Aperture Answer: elementary -dedicated chest, dental unit, trauma imaging equipment -flat piece of lead having a central opening with a size and shape that determines the size and shape of x-ray Question: Cone/cylinder -used for relatively field size (paranasal sinuses)Answer: circular, lead-lined, slide into place in the tube head or onto the collimator housing Straight-prox and dist diameters identical Flare-dist diameter than prox diameter -limited use, more efficient bcs beam restriction is closer to anatomy Question: Disadvantages of aperture and cone beam Answer: have a opening size, only one field size at a given distance Question: Answer: quantity, no affect on quality Question: Answer: controls quality, affects Question: NCRP guideline for manual collimation must be within _____ of the SID.Answer: 2% Question: beam limitation-PBLAnswer: sensors located in Bucky tray or other IR holder signal the to open or close accordingly to the IR size being used, will provide a small unexposed border on all sides of the finished image -required by the NCRP to be withi Question: PBL by NCRPAnswer: -required by the NCRP to be within 3% of SID for a single side and within 4% of SID for all 4 Question: NCRP for manual collimationAnswer: within 2% of the Question: assembly-light localization apparatusAnswer: small light bulb to illuminate the and a 45-degree angle mirror to deflect the light. Question: T/F For the x-ray light field and x-ray to correspond accurately, the x-ray tube focal spot and the light bulb must be exactly the same distance from teh center of the mirror.Answer: Question: factors for patient safetyAnswer: high kVp, low mAs -also good bcs heat to x-ray tube is lower and tube life is extended Question: Three-phase or high frequency Answer: stationary equipment, constant potential waveform, reduced patient dose Question: Inherent Answer: built in, permanent -window of envelope (.5 mm Al) -thin layer of oil coolant/insulation surrounding the x-ray tube -tends to increase as tube ages, tungsten deposits Question: summaryAnswer: less than 50 kV = .5 mm Al 50-70 kV = 1.5 mm Al more tha 70 kV = 2.5 mm Question: Radiosensitive Answer: gones, lens, -froming organs Question: Whose to shieldAnswer: all women under 55, all men 65 Question: shieldingAnswer: easier and more on males than on females Question: When to the gonadsAnswer: -when diagnostic objectives permit -when pt is of reasonable reproductive age -when lie in or within 5 cm of the collimated field Question: Contour shaped Answer: effective for gonads, shaped to male reproductive organs, held in place by disposable briefs, effective for oblique, erect, and fluro exams Question: shieldsAnswer: leaded material casts a shadow within the illuminated field that corresponds to shielded area, inially expensive but one time expense, can be used without contacting fields, NOT TO BE USED IN FLUORO. Question: Mammography equipment with a molybdenum target has how much ?Answer: .025-.03 mm filtration Question: window in mammo is made of what?Answer: beryllium-low number (4) Question: filtrationAnswer: thin sheets of aluminum that are , collimator and its mirror Question: Why use PA instead of AP or spine?Answer: decrease dose to breast tissue to .1% of that received in AP, considerations are minimal Question: T/F Entrance skin dose is greater than exit dose.Answer: True -place organs away from the entrance beam Question: Perform these exams in PA projection when .Answer: Skull, chest, abdomen, scoliosis series, Question: good Answer: helps gain 's trust and confidence with a thorough explanation Question: lead during fluoroAnswer: under patient Question: Minimum response/reaction Answer: length of the exposure possible with a particular AEC Question: If the minimum response time is too high, how is this .Answer: needs fixed or will have excess density -preferable to ma, but may decrease kV Question: Rare earth Answer: film/screen radiography -four faster than calcium tungstate phosphors Question: of digital fluoroAnswer: lower patient dose due to x-ray are pulsed not continuous Question: Answer: function to remove a large percentage of scattered radiation mostly from Compton , improve radiographic contrast Question: air-gap Answer: limited to imaging fairly thin parts (thick and dense tissues would excessive and impractical radiation exposures) Question: equipment must be properly calibrated to give predictable results. What two need to be checked?Answer: and reproducibility Question: linearityAnswer: adjacent mA stations should be consistent 200 mA should be 2x rate as 100 mA, any variation in output intensity must not exceed 10% Question: Answer: consistency in exposure output during repeated exposures at a particular setting, any variation in output must not exceed 5% Question: High ratio grids with low Answer: BAD, discouraged of unnecessary exposure required Question: high grids affect on positioningAnswer: positioning latitude Question: low gridsAnswer: used in mobile radiography, more latitude Question: 8:1 grid good for what kV ?Answer: up to 90 Question: 16:1 grid good for what kV ?Answer: 100 kV or Question: 10:1 or 12:1 grid used in what type of ?Answer: general fixed Question: T/F Moving grids call for less exposure than grids.Answer: False. They more exposure. Question: Ways to decrease patient fluoro Answer: -decrease length of exposure -use last image hold -keep pt as close to II as possible -use brightness control setting with high kV, low mA -minimize "boost" and "mag" modes, low pulse rate -collimate to smallest field of view Question: Ways to decrease patient dose cont.Answer: -use practical pulse rate -change tube angle or patient position to spread dose over larger area Question: NCRP guidelines for x-ray tube leakageAnswer: less than 100 mR/hr 1 meter from Question: Source-Skin distance for all radiographic (NCRP)Answer: no less than 12 in -12 in mobile radiography -15 inches in stationary radiography Question: (NCRP) Fluoro tabletop Answer: than 10 R/min Question: Where should the focal spot location be ? (NCRP)Answer: outside of tube Question: How often should screens be cleaned and checked? (NCRP)Answer: every 6 Question: (NCRP)What type of switches are used?Answer: dead-man Question: (NCRP) How should the patient be to the radiographer?Answer: RT should be able to see and with the patient at all times Question: NCRPAnswer: national council on radiation and measurements Question: Principal of x-ray tube filtrationAnswer: reduce patient skin |
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