Equipment Operation and Maintenance
Grid-controlled tube Designed to turn on and off rapidly, providing short precise exposures Use in fluoro and in capacitor discharged (condenser-discharge) mobile units Uses a molybdenum focusing cup
FLUOROSCOPY INPUT PHOSPHOR PHOTOCATHODE OUTPUT PHOSPOR LARGE DIAMETER CESIUM IODIDE X-RAYS LIGHT PHOTOCATHODE LIGHT ELECTRONS OUTPUT PHOSPOR SMALLER DIAMETER ELECTRONS LIGHT
FLUORO CONT. FOCUSSING LENSES VIDICOM/PLUMBICON BEAM SPLITTING DEVICE mA ABS AGC or ABC
# OF INPUT LIGHT PHOTONS FLUX GAIN=# OF OUTPUT LIGHT PHOTONS # OF INPUT LIGHT PHOTONS MINIFICATION GAIN = Diameter of input (squared) diameter of output (squared BRIGHTNESS GAIN: minification x flux
Trifield Tubes 25/17/12 smaller diameter of input phosphor reduces: field of viewmagnification minification gain dimmer image
Larger film format greater the # of films =higher patient exposure Cinefluoroscopy rapidly obtained photospot image (35mm film)15,30,60,90 frames per sec. cardiac cath Spot film 12 frames per sec smaller film size cassette loaded
FLUORO QUESTIONS #9,24,30,36,38,40,44,47,54 63, 69,70
AEC
Collimation and AEC Photodiode ion chamber light sensitive under table, behind cassette ion chamber charge sensitive above bucky and cassette #10,14,25,27,34,81,92,102,113,
CIRCUITS
Self induction = autotransformer and choke coil Mutual induction =High voltage transformer & filament circuit V = VS = NS VP= NP I = NS = IP NP=IS
Rectifiers Filament circuit rheostat filament circuit
Star and wye configurations Motor and generators Rheostat Star and wye configurations transformer windings in 3-phase circuits 5,20,23,26,35,45,46 ,51,52,53,74,77
THREE PHASE/SINGLE PHASE HU single phase=ma x time x kvp three phase/ 6 pulse ma x time x kvp x 1.35 three phase/12 pulse ma x time x kvp x 1.41
VOLTAGE RIPPLE 100% 13% 4 or 3% ?’s 35,64,96,97,99,105,106 Single phase three phase 6 pulse three phase 12 pulse 100% 13% 4 or 3% ?’s 35,64,96,97,99,105,106
Tomography Thinner the cut the _________the angle 43
QUALITY CONTROL TESTS SPINNING TOP TIMER WIRE MESH SCREEN/FILM CONTACT PENETROMETER KVP AND CONTRAST STAR PATTERN FOCAL SPOT SIZE CUTIE PIE ROENTGEN DOSIMETER WISCONSIN TEST TOOL KVP IN BEAM GEIGER RADIOACTIVITY
spinning top tests Spinning top tests half wave/single phase = exposure time x 60 Full wave/single phase = exposure time x 120 Three phase –exposure time =arc size/360 timers and rectifiers dots and dashes(12 dots of 1/10sec, 24 dots of 1/5 sec, 6 dots for 1/20 sec) synchronous spinning top solid arc #18,28,41,50,57,61,66,65,68,
TUBE LIFE/HEAT LOAD #6,12,16,33,44,73,77,101,
Mobile radiography, CT, Misc Capacitors- temporarily stores energy-no battery 2,3,4,22,37,42,55,58,71,78,87,88,120
DIGITAL Corectec
Misc. Light absorbing dye in screens reduce diffusion of fluorescent light