How CT / MSCT works Imageaquisition:. How CT / MSCT works.
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Transcript of How CT / MSCT works Imageaquisition:. How CT / MSCT works.
How CT / MSCT worksHow CT / MSCT worksHow CT / MSCT worksHow CT / MSCT works
Imageaquisition:Imageaquisition:
How CT / MSCT worksHow CT / MSCT worksHow CT / MSCT worksHow CT / MSCT works
Gerätetechnik: Gerätetechnik: GenerationenGenerationen
Gerätetechnik: Gerätetechnik: GenerationenGenerationen
Single vs Multirow Single vs Multirow Single vs Multirow Single vs Multirow
4 Slices 4 Slices +??+??
1 Slice1 Slice
X-Ray tubeX-Ray tube
Multirow Detector CT:Multirow Detector CT:Multirow Detector CT:Multirow Detector CT: Fixed Matrix DetektorFixed Matrix Detektor
Multirow detector Multirow detector CT:CT:
Multirow detector Multirow detector CT:CT:
Adaptive Array DetectorAdaptive Array Detector
Multirow detector CT:Multirow detector CT:Multirow detector CT:Multirow detector CT:
Adaptive Array DetectorAdaptive Array Detector
Image Plane
DetectorSlice broadening by spiral interpolation
Collimation Slice Sensitivity Profile (SSP)
increasing pitch -> Wider slice profile
Single Detector CTSingle Detector CTSingle Detector CTSingle Detector CT
Provided by Siemens Erlangen
Pitch 2
Pitch 3 Pitch 5 Pitch 7
Pitch 1 Pitch 1.5
Blurring
Single vs MultirowSingle vs MultirowSingle vs MultirowSingle vs MultirowSingle-slice
scanner
Volume Zoom
SURE VIEWProvided by Siemens Erlangen
„„Magic Triangle“Magic Triangle“„„Magic Triangle“Magic Triangle“
Larger Volume
Shorter Scan Time
Isotropic Resolution
Provided by Siemens Erlangen
ResolutionResolutionResolutionResolution
Isotropic ImagingIsotropic Imaging
isotropic voxel
No isotropic
voxels
SpeedSpeedSpeedSpeed
64 slices /rotation64 slices /rotation Rotation times < 0.5s possible Rotation times < 0.5s possible
Dynamic studiesDynamic studies
CT -- BenchmarkingCT -- BenchmarkingCT -- BenchmarkingCT -- Benchmarking
Geometric Resolution:Geometric Resolution:- xy:xy: 0.3-0.5mm 0.3-0.5mm- z: z: 0.6mm 0.6mm
Radiometric Resolution:Radiometric Resolution:- 12bit data = 4096 shades of gray12bit data = 4096 shades of gray- Hounsefield Units (HU): Hounsefield Units (HU):
Minimum:Minimum: -1024 HU = air-1024 HU = air Zeropoint:Zeropoint: 0 HU = water0 HU = water Fat:Fat: -120 – 80 HU-120 – 80 HU Bones:Bones: > 200 HU> 200 HU
CT -- BenchmarkingCT -- BenchmarkingCT -- BenchmarkingCT -- Benchmarking
Time Resolution:Time Resolution:- Standard: Standard: 0.5s0.5s- Cardiac Mode: Cardiac Mode: 0.33s0.33s
Maximal Scanlength:Maximal Scanlength:- ca. 150cmca. 150cm
ResolutionResolutionResolutionResolutionThickness 5.0mmIncrement 2.5mm
Thickness 2.5mmIncrement 2.0mm
Thickness 1.25mmIncrement 1.0 mm
ResolutionResolutionResolutionResolutionThickness 5.0mmIncrement 2.5mm
Thickness 2.5mmIncrement 2.0mm
Thickness 1.25mmIncrement 1.0 mm
CT – New:CT – New:Dual Source CTDual Source CT
CT – New:CT – New:Dual Source CTDual Source CT
CT & RadiatenCT & RadiatenCT & RadiatenCT & Radiaten
CT ~ 10% of Xray ExaminationsCT ~ 10% of Xray Examinations CT CT source of ~50% medical source of ~50% medical
related radiationrelated radiation Incresases stochastic risk for Incresases stochastic risk for
cancer development:cancer development:- 1mSv Totalbody irradation 1mSv Totalbody irradation risk for risk for
lethal cancer is increased by 5%lethal cancer is increased by 5%- USA: maybe about 500 children dying a USA: maybe about 500 children dying a
year by cancer due to CTyear by cancer due to CT