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Prepared By: S. Ehtesham Al Hanif (Hridoy) [0510035

BIO (BIO-MEDICAL) ENGINEERING CT-SCAN

ME 471- BIO-ENGINEERING / BIO-MEDICAL

TOPICS: CT-SCAN

Prepared By,

S. EHTESHAM AL HANIF (HRIDOY)

STUDENT ID: 0510035

E-MAIL: [email protected]

MOBILE: 88-01670839383

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FUNDAMENTALS OF CT SCAN MACHINE

(Radiography and Computed tomography)

Tomography X-ray radiography

Computed tomography means reconstruction of an object in a tomographic

plane by the computer data processing.

Effect of the CT Scanner

1. Patient doesn't suffer from an overload such as a pain or a shock during

examination.

2. More clear images can be obtained than those by ultrasound diagnostic

equipment and radio isotope apparatus.

3. Since accurate attenuations coefficient of a tissue can be obtained and

quantitative analysis is made possible, not only the qualitative but also

the quantitative change can be known.

4. Reduced X-ray does and increased amount of information.

5. Because of the digitalized attenuation coefficient, reliable image for

diagnosis can be freely obtained by the data processing system.

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The General Concept of CT

(1) Block diagram of CT

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(1) X-ray profile data for image reconstruction are collected bythe linear translation movements of the X-ray tube

(2) Aftercollecting one X-

ray profile data,

the X-ray tube

and detector

rotate and the

second X-ray

profile data are

collected by the

second linear

translation

movement.

(3) Many profile data are collected by repeating thistranslation and rotation in area of 180 degrees (sometimes

240 or 360 degrees).

(4) Many profiles thus obtained are converted into one image by the imagereconstruction.

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- Rotate-Rotate (R-R) system -

(1) The X-ray tube generates pulse X-rays with the rotation of the X-ray tube and detectors.

(2) X-ray profile data are collected for every pluse X-ray generates and a lot of profile

data are collected by repeating this rotation for 360 degrees.

(3) The scan time is short because there is no such linear translation movement as

Translate-Rotate system.

(4) Many detectors filled with high pressure Xenon gas are used.

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Types of CT

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Comparison Table of CT's of Respective Generations

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3) 9. Back-projection Method

Note: In this case, the same result as the original image is obtained

by chance, but in general the image obtained by the back-projection is little blurred

from the original image. Refer to next page.

Diagram of Image Processing by CT Scanner

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