What is CT Scanner

CT ScannerThe use of radioactive substances is part of the nuclear technology is relatively fast benefits for the community. This is due to radioactive substances have specific properties, which are not owned by unusr-unusr other. By utilizing radioactive properties, so many complicated issues which can be simplified so that the solution becomes easier.
   One of the properties of nuclear radiation that is able to penetrate solid objects. This property is widely used in radiography technique that is shooting the inside of an object using nuclear radiation such as x-rays, gamma rays and neutrons. The result of the shooting were recorded in x-ray film.
Radioactive substances are widely used in industry and medicine. In the field of medicine, radiography is used to find out the inside of organs such as bones, lungs and heart. In radiography using x-ray film, then the observed object is often covered by a network of other structures, to obtain a shadow image pattern which is dominated by the structure of the unwanted tissue. This will confuse the doctors to diagnose these organs. To overcome this, the development of more sophisticated technology, ie CT-Scanner (Computed Tomography Scanner) using nuclear radiation such as neutrons, gamma rays and x-rays.
CT Scanner SystemCT Scanner equipment consists of three parts: image processing systems, computer systems and control systems.
Image processing system is the part that is directly confronted with the observed object (patient). This section consists of x-ray sources, control systems, detector and data acquisition. X-ray radiation creep is straight, not influenced by electric and magnetic fields and can lead to substance fosforesensi to glow. X-rays can penetrate solids with high penetrating power. To find out how many x-rays are emitted into the patient, then the equipment is also equipped with control systems that receive input from the computer.
Output part of the image processing system, is equipped with a set of detector data acquisition system. The detector is a tool to change the physical quantity-in this case a radiation-electrical quantities. Radiation detectors are often used is the gas ionization detector. If the tube is pierced by a radiation detector, the ionization will occur. This will generate an electrical current. The greater the interaction of radiation, the electric current arising semakn too big. Another commonly used detector is the detector crystal solids. The composition of the detector is installed depends on the type of CT scanner generations. But in terms of function of all detectors are the same, namely to identify the intensity of the Sina-x seletalh past the object. By comparing the intensity at the source, the attenuation caused by propagation in the object can be determined. By using the data acquisition system so the data from the detector can be incorporated in a computer. The system consists of data acquisition and signal conditioning system interfacae (interface), analog to the computer.
Computer Systems and Control Systems
Computer part responsible for the overall system of the CT scanner, which controls the x-ray source, store data, and construct tomographic images. Computer consists of processor, array processor, hard drive and input-output system.
Processor or CPU (central processing unit) has a function to read and interpret instructions, melakukak execution, and store the results in memory. CPU data bus that used to have 16.32 or 64 bits. This type of computer used computer and can be micro mini computer, but must meet the performance and speed of CT Scanner system bai. Hard drive has a function to store data and software.
CT Scanners are generally equipped with two monitors and keyboards. Respectively as the operator station and the viewer station and both have different tasks. Operation Station has the function as the control operator to control several parameters such as voltage anode scan, scan time and the amount of filament current. While the viewer station has a function to manipulate the image processing system. This section has a control system connected to the output system such as a hard copy of the film, magnetic tape, and paper print outs. From this passage work to be done to diagnose the scanning results.
Reconstruction
The last part is the reconstruction of the CT Scanner. Many methods can be used to reconstruct tomographic images, ranging from back projection to convolution.
Back projection method is widely used in medicine. This method uses the distribution of the pixels are smaller than a transverse incision. Pixel based on the value of linear absorption. Then the pixels are arranged into a profile and formed a matrix. Reconstruction was done by adding each other between the elements of the matrix.
To get a better image reconstruction, convolution method is used. Reconstruction process of convolution can be expressed in mathematical form the Fourier transformation. By using the convolution and Fourier transformation, the radiological image can be manipulated and corrected so that the resulting picture is better.