ct principles, basics to basic hystory of ct

8/17/2019 CT Principles, Basics to Basic Hystory of CT

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CT Principles

Back to BasicsHistory of CT

CT Principles

Back to BasicsHistory of CT


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Discovery of X-ray

• Prof. Wilhelm ConradRöntgen

(German Physicist)

• November 8, 1895 – Discovered accidently working

in his Laboratory at University

of Würzburg

– As the Nature of the Ray wasUnknown, he called it X-Ray

• Röntgen received the first

Nobel Prize in Physics in1901

• However, he refused to takeout any patents in order thatthe world could freely benefit from his work


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Inventor of X-ray Tube

• William David Coolidge

(1873-1975)

– 1905 Joined GE Research

Laboratory

– 1913 GE Engineer whodeveloped the “Coolidge” X-

Ray Tube

– Became VP & Director of GE

Research Laboratory

– 1975 Elected into National

Inventor’s Hall of Fame

– 83 Patents to His Credit


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RadiographicRadiographic IImagingmaging

Computed TomographicComputed Tomographic IImagingmaging

Conventional RadiographyConventional Radiography

Conventional TomographyConventional Tomography

X-Ray & Tomography

CTCT


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The Meaning of Tomography

• 1920 (Early) – Technique for imaging a layer of

body had been developed andcalled “Body sectionRadiography” or“Stratigraphy”(Stratum meanlayer)

• 1935 – Grossman refined the technique

and labelled it “Tomography”(From the Greek tomos meaning

section)

• Computed Tomography(CT) meaning transverse

section (cross section) ortransverse axial tomography


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Generations of CT Scanners

– 1971 First Generation – 1972 Second Generation

– 1975 - Present Third Generation

– 1977 – Present Fourth Generation


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First Generation CT

One Detector Translation/Rotation with Parallel Beam


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TranslateTranslate//Rotate with Single Detector Rotate with Single Detector

With single detector can onlyWith single detector can only

acquire one view at a timeacquire one view at a time

1st Generation CT Scanners

(Translate/Rotate)

• EMI Scanner (Prototype)

• Single Detector

• Mechanically Complex

• Long Scan Times (4-5Mins)

• Extremely Slow

• Head Scan Limited

• Required Water Bath

• Fixed Anode X-Ray Tube – Low mA


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Second Generation CTMultiple Detectors Translation/Rotation with Small Fan Beam


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TranslateTranslate//Rotate withRotate with MultipleMultiple Detector Detector ss

Significant ImprovementSignificant Improvement

Over 1st GenerationOver 1st Generation

2nd Generation CT Scanners

(Translate/Rotate)

• EMI 1010 & 5005 Scanner

(1972)• Multiple Detectors

• Mechanically Complex

• Shorter Scan Times – 20 to 90 Sec

• Head/Body Scan Capable

• Required Water Bath forHead Only Scanner

• Rotating Anode X-RayTube

– Low mA, Long Scan Time – Poor Tube Life, 350 KHU

Tube


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Third Generation CT

Multiple Detectors Rotation/Rotation with Large Fan Beam


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TranslateTranslate//Rotate withRotate with MultipleMultiple Detector Detector ss

Current Geometry of ChoiceCurrent Geometry of Choice

for All Manufacturersfor All Manufacturers

3rd Generation CT Scanners (Rotate/Rotate)

•GE 8800 (1975) – Multiple Detectors in “Fan Beam”

– Array of detectors and tube rotatearound the patient for fasterscanning

– High mechanical stability

– Detectors always in x-ray beam,allow good utilization of the x-ray beam

– Good tube-patient-detectorsgeometry

• Faster Scan Times – 4.9 Sec

– Long Recon Times

•Rotating Anode X-Ray Tube – Higher Pulsed mA – Poor Tube Life, 500 KHU Tube


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LightSpeedLightSpeed1616with Xtream Technologywith Xtream Technology


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Fourth Generation CTDetector Ring Source/Rotation with Large Fan Beam

LightSpeed Continuum LightSpeed Platform


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9 Productsin 7 Years

on 1 platform!

LightSpeed16LightSpeed

Plus

Our commitment to our Customer is our Continuum.

LightSpeed

Ultra

HiSpeed

QX/i

LightSpeed

QX/i

1998 2000 2001 2002 2002 2003 2003

LightSpeed

Pro16LightSpeed

RT

LightSpeed

VCT

2004

LightSpeed Continuum…LightSpeed Platform

LightSpeed

Pro32


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Can All Scanners do

this?

1. Can you do a Coronary CTA in 5 heartbeats?

2. Can you perform a gated study of the chest in 10-12 seconds?

3. Can you scan the whole body in 10 seconds with sub-millimeter resolution?

4. Can your detector read out a full 64 channels per rotation?

5. Does your CT detector feature backlit diode technology?6. Does your system have an isotropic detector that delivers 0.35mm resolution?

7. Can you acquire a coronary CT image with a temporal resolution of 43 milliseconds

and an actual-not effective-mAs of 280?

8. Does your system deliver up to 800 mA?

9. What is the maximum table weight and scannable range?

10. Is all recon and transfer on your system performed at 16 images per second?

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