CT Scan History PDF

1919 Godfrey Newbold Hounsfield born in Notthinghamshire, England 1924 Allan Macleod Cormack develops solution to the mathematical solutions in CT such as algorithm 1930 Allesandro Vallebona proposed a method to represent a single slice of the body on the radiographic film (TOP...

1919 Godfrey Newbold Hounsfield born in Notthinghamshire, England 1924 Allan Macleod Cormack develops solution to the mathematical solutions in CT such as algorithm 1930 Allesandro Vallebona proposed a method to represent a single slice of the body on the radiographic film (TOPOGRAPHY) 1951 Godfrey Newbold Hounsfield joins EMI limited 1967 Godfrey Newbold Hounsfield: 1st CT scanner at EMI Research Laboratories; “EMI MARK 1” 180 translation/1 degree rotation scanning time /20 mins per slice 1970 Godfrey Newbold Hounsfield first demonstrated CT technique 1971 First Brain CT; First Clinical CT in London 1972 First clinical CT scanners were installed 1973 Dr. Robert Ledley first clinical scan in USA whole body(320x320) 1974 Godfrey Newbold Hounsfield first body scan in a prototype of the EMI body scanner “convolution & back projection” 1976 SOMATOM scanners; Fan beam principle 1978 TOPOGRAN/ SCONOGRAM 1979 Hounsfield & Cormack received Nobel prize in physics 1980 CT became wide available (1024x1024) 1981 512x512 matrix with constant image 1984 Opti CT tube with 70cm gantry opening(+/- 25 deg) 1986 Osteo CT : Bone Mineral CT Xenon CT : demonstrate regional cerebral CT flow Dexa CT(Dual Energy X-ray Absorptiometry) 1987 Continuous rotation flying focal spot; CT tube dura 351 1988 Multi Slice CT 1990 Toshiba: Spiral/ Helical CT 1991 Intuitive Mouse Driven Window Interspace/ Twin slice CT 1992 CT angiography/ multi slice/ 4 slice(0.5s) 1994 Routine sub second spiral CT 1996 spiral “4” everything. Neuro & high resolution spiral CT 2002 16 slice helical CT 2004 64 helical CT is introduced 2005 SIEMENS: Dual source CT 2007 TOSHIBA: 320 helical CT CT SCAN XRT Shape and Degree Movement Scanning time Detector NOTES GENERATIONS Of Beam Stationary Pencil beam shaped Yoke align XRT, 1st Linear tube 4.5 - 5.5 1 - 2 Nal coupled with yoke Patient and movement minutes : scintillating Parallel beam detector. rectilinear crystals PMT as geometry was first pencil beam detectors (2cm x used by Hounsfield (Translate Only for brain scanning 2cm & 13 mm) (1973) rotate) scan (IT:9DAYS) 1 degree rotation 180deg xrt rot Stationary xray Translate 2nd Narrow Fan beam 18s/20s/30s per 5 - 30 detectors A:speed tube with diala Rotate Generation shape slice (coupled w/yoke) D:INCREASED SCATTER, INCREASED INTENSITY (IT: 3.5 min) TOWARDS THE EDGES OF THE BEAM 10 degree rotation 180deg xrt rot COMPENSATION:BOW TIE FILTER Wide fan beam 3rd Rotating with Rotate- Rotate 0.35 - 10 750 - 1000 D:RING ARTIFACT diala oil seconds detectors (width: 30 - 60 (curvilinear) 360 rotation for COMPENSATION: degree arc) Employs thin elimination of each acquisition SOFTWARE tungsten septa yoke - continuously CONNECTED IMAGE to reject rotating fan RECONSTRUCTION scattered beam scanning ALGORITHM radiation Wide fan beam (60 4th Rotating XRT with Rotate- 0.5 seconds 4800 fixed A:SHORTER degree; used a 400 diala oil stationary detector array SCANNING TIME, degree rotation) detector / w/ detector ring FREE OF RING for each complete 360 ARTIFACT acquisition rotation D:INCREASED PT DOSE; MOTION ARTIFACT EBCT scanner and 5th Electron gun emit Stationary – High-speed Stationary Dedicated to DSR Scanner Wide e- beam and Stationary scanning detector cardiac imaging fan beam? tungsten target Developed EBCT rings Dynamic (both source and (built to spatial detectors don’t compensate for IMATRON scanner move) motion of heart) High speed CT scanners /Ultra speed CT 6th 2 x-ray tubes Wide fan beam? Moving gantry High-speed 2 sets of XRT and Detector stationary scanning detectors offset by 90deg (cardiac imaging stationary DUAL SOURCE (Slip ring too) (offset by CT/SPECTRAL (offset by 90deg) technology) Excel in 3d 90deg) CT Multiplanar reformation ROTATING XRT W/ Reduces motion 7th Cone beam Moving gantry High-speed Flat panel DIALA OIL? artifact (DUE TO and patient scanning detector SPECIALIZE couch Helical/ COMPUTER FLAT PANEL CT Spiral SYSTEM) Can SCANNER/TURBO cover any CHARGED SPIRAL CT examination