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MULTISLICE CT. SINGLE vs MULTI. CT EVOLUTION. 1998 MULTISLICE CT SCANNERS INTRODUCED AT RSNA MEETING. SINGLE SLICE CT LIMITATIONS. SPEED PERFORMANCE 3D,MPR,MIP Z-AXIS RESOLUTION MPR LOW ACCURACY 360 LIA ( IMAGE QUALITY & ARTIFACTS) CT ANGIO LIMITATIONS MORE INTRAVENOUS CONTRAST.
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SINGLE SLICE CT LIMITATIONS • SPEED PERFORMANCE • 3D,MPR,MIP Z-AXIS RESOLUTION • MPR LOW ACCURACY • 360 LIA ( IMAGE QUALITY & ARTIFACTS) • CT ANGIO LIMITATIONS • MORE INTRAVENOUS CONTRAST
SLICE THICKNESS IN SINGLE SLICE CT DETERMINED BY: • PITCH • PRE-PATIENT COLLIMATION
MULTISLICE CT COLLIMATION • BEAM FALLS ON THE ENTIRE MULTIROW DETECTOR ARRAY 8 MM WIDE BEAM FALLING ON FOUR DCETECTORS CAN PRODUCE: 4 –2MM SLICES
SINGLE SLICE SPIRAL MULTISLICE FAN CONE BEAM GEOMETRY
BEAM GEOMETRY • AS THE NUMBER OF DETECTORS IN A MULTIROW DETECTOR ARRAY INCREASES THE BEAM BECOMES WIDER TO COVER THE 2D DETECTOr ARRAY. LARGER # OF ROWS IN THE DETECTOR ARRAY WILL RESULT IN A WIDER BEAM IN Z-AXIS DIRECTION ( CONE BEAM)
POST DETECTOR COLLIMATION IN MULTISLICE CT • THE COLLIMATORS ARE POSITIONED BETWEEN DETECTOR COLUMNS.
IMAGE RECON IN MULTI SLICE CT • SPECIAL FAN BEAM RECON ALGORITHMS HAVE BEEN DEVELOPED
DAS • ALMOST ALL MULTISLICE CT SCANNERS ARE BASED ON III GENERATION SYSTEM DESIGN ROTATE-ROTATE
GENERATOR • HIGH FREQUENCY GENERATOR 60 KW OUTPUT.
X-RAY TUBE • ROTATING ANODE TUBE WITH VERY HIGH HEAT CAPACITY