Block Diagram of the CT Scanner

CT scanner

The CT Scanner is the abbreviation of computer tomography scanner. The invention of CT Scanner in 1970 was made possible by a previously established insight and development of the dedicated minicomputers.

The operation of CT Scanner can be described in following steps.

1)      High voltage supply drives the x-ray tube that can be mechanically
rotated along the circumference of a gantry.
detectors, which are fixed in a place around the circumference of the
gantry in a large quantity.
the output of the detector scanner which is opposite to the x-ray
tube.
 made by the computer.
  cross the section of patient.

2)      Patient is lying in a tube in the center of gantry.

3)      The X-rays passes through the patient and produces an image on

4)   Microcomputer sense the position of tube in the gantry and samples

5)       A calculation based on the data of a computer scan of the tube is

6)    The O/P unit then produces a visual image of a transverse plane

7)    The   output   may   be   displayed   on   the   cathode   ray tube or photographed  

      with a camera to produce a hard copy record.

Detector operation and construction: -

Detectors consist of ionization chambers filled with a gas such as xenon, sealed at both ends and having two conductors forming a capacitor on the sides.

A high DC voltage is applied to the capacitors an x-rays entry. The chamber ionizes the xenon item causing it to migrate to capacitor plate and causing a current in the high voltage load. This current is proportional to the radiation and is fed to the computer as data for computing the image.

The advanced model of CT scanner create image at an angle other than 90° by tilting the gantry.

Application

     1) Its major application is in medical field. In medical, it is used to

Detect the injury in the human brain

2)     It is used to detect inner wounds.