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Transcript of SAIBAL-CT
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COMPUTED
TOMOGRAPHY
Saibal Kumar Kar
3rd Year , B.M.E
Netaji Subhash Engineering College
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CONTENTENTS
What is CT
Basic Principle Generation of CT
Image Reconstruction Techniques
CT Detectors
Artifacts in CT
Application of CT
Summary
Referance
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What is CT
CT is a digital imaging technique ,produces several axial or sliceor cross-sectional images of different parts of our body such as
bone ,mussels , heart, human brain, etc..It is normally abackproecting image construction procedure.
Tomography is a Greek word which comes from , tomosmeans slice and graphia means describing.
CT was first invented by Dr. G.N.Hounsfield at the CentralResearch Laboratories of EMI Ltd , UK, in 1967 & was firstpublicly announced in 1972.
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y CT produces cross-sectional images by measuring the
narrow beam of X-Ray f0r different and direction.
y The main principle of CT depends on Beers-Lamberts
law-y I=Io.e
y CT produces cross-sectional images by measuring the
narrow beam of X-Ray f0r different and direction.
y The main principle of CT depends on Beers-Lamberts
law-y I=Io.e
Basic Principle
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Generation of CT:
y 1st Generation : One source coupled with one or two
detectors . It takes 4-5 minutes to construct an image.
y 2nd Generation: One source multidetector (at least 30detectors)system.18-20 seconds required for one image.
y 3rd Generation: One source multidetector(100-300
detectors)system. Here source &the detectors are
coupled. It takes 7-12 seconds.y 4th Generation: One source coupled with 2000 fixed
detectors.Now-a-days this generation is mostly used.
y 5th Generation of CT has also been developed now.
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IMAGE RECONSTRUCTIONIMAGE RECONSTRUCTION
y There are 3 processes,
S
imple Back Projection, Interative Method,
Analytical Method.
Now-a-days analytical method is mostly
used.
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The main detectors, used in CT, are asfollows,
1.Scintilation crystal with PMT,
2.Inert Gas ionisation detector,
3.Scintilation crystal with Photodiode.
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Artifacts of CT:
Artifacts
Patientrelated
PatientMovement
PartialVolume
Scannerrelated
SamplingAccuracy
BeamHardening
Detectornon-
uniformity
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CT scan is normally recommended to:
Diagnose muscle and bone disorders, such as bone
tumors and fractures. Pinpoint the location of a tumour, infection or blood clot. Guide procedures such as surgery, biopsy and radiation
therapy. Detect and monitor diseases such as cancer or heart
disease. Detect internal injuries and internal bleeding. CT scanning is useful to get a very detailed 3-D image of
certain parts of the body, such as soft tissues, the pelvis,blood vessels, the lungs, the brain, abdomen, and bones.
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SUMMARY
CT image reconstruction technique have been
continuously developed over the years to match
the advancement in new acquisition hardware
and new acquisition technique.
Image explosion from new CT scanners,
advanced visualization are needed to improve
the productivity of radiologists.Faster & better
tools are constantly developed.
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REFERANCES
by
1.Biomedical Instrumentation
by R.S.Khandpur.
2.Reference taken from
Dr.Sukumar Roy(HOD-B.M.E),
Mr.Samir Ghosh(FACULTY-B.M.E),
3.www.google.com