Medical brain notes 7

  NEURORADIOLOGY - THEIMAGING OF THE BRAIN A doctor normally diagnoses and treats the patient through observations of symptoms, history etc. Many a times when it becomes necessary to know the location, extent and damage caused by a disease lying inside the body, radiology- neuroradiology becomes helpful and and necessary. Radiology-neuroradiology consists of Screening, X-Rays, Ultrasound, CT scan, and MRI etc. X-Ray : The “miraculous rays” X-Rays which could look-make structures inside the body were discovered in 1895 by a German scientist Mr: Roentegen. Thereafter these rays have been used in all possible innovative ways in the medical field. Sunrays, X-Rays, Microwave, Radio waves are all electro magnetic rays in scientific terminology. The only differentiating factor between them is their energy- content. Radio and television waves do not have much energy and so though they are present all around us in innumerable numbers, they cannot harm us and we are still alive. The energy f...

  X-Ray : The “miraculous rays” X-Rays which could look-make structures inside the body were discovered in 1895 by a German scientist Mr: Roentegen. Thereafter these rays have been used in all possible innovative ways in the medical field. Sunrays, X-Rays, Microwave, Radio waves are all electro magnetic rays in scientific terminology. The only differentiating factor between them is their energy- content. Radio and television waves do not have much energy and so though they are present all around us in innumerable numbers, they cannot harm us and we are still alive. The energy from the X-Rays is 10,000 to 15,000 times more powerful than light and therefore can penetrate through objects. An amazing fact of nature is that the human eye can perceive only the sun rays and the rest of the rays are invisible to us. The common X-Rays only give a rough picture of the skull or a one dimensional picture, but the depth of any feature cannot be judged, e.g. if there is a tumor inside thebrain i...

  C T Scan : (Computed Axial Tomography) X-rays are used to give us a picture of different parts of the body. However, since we are now discussing about the diseases of the brain, it is necessary to know how X-Rays are helpful in this context. In the previous chapter we learned that the brain is well protected in the skull and therefore X-Rays are only able to give us the information of the skull. In-depth information regarding the inner structure cannot be obtained. The CT scan machine invented by a British Scientist Honsfield solved this problem. CT scan or CAT Scan is Computed Axial Tomography. CT scan also uses the X-Ray technology but with the help of the computer a three-dimensional view of the body is created. If there is a tumor in the brain, its depth and position can be determined by dividing the brain into imaginary parts like slices of bread, and each part is X-Rayed from various angles. The computer then calculates and creates a three- dimensional picture, which determ...

  CT Scan Machine : The CT Scan Machine is like a cubical box and is called Gantry. Within this box lies a two feet long circular tunnel. The stretcher like table on which the patient lies, can be moved in all directions upward, downward and side ways. The part of the body to be examined is kept at the center of the tunnel. The X-Ray tube lies in the middle of the tunnel, and rotates in a circular motion photographing the body part from each angle. These photographs are reflected on the detector, a computer carries out accurate calculations, divides the area into slices and then with the help of laser camera photographs are taken. The entire procedure takes about 15 to 30 minutes and during this time the patient has to lie still. On an average twenty photographs are taken on a 14" × 17" X-Ray film, which are interpreted by the radiologist and a report is made. A CT scan can gives detailed informationof organs right from the brain to the spinal cord and lungs to the stomach, s...

  MRI Machine : The MRI machine is cylindrical in shape, made of a powerful magnet. The patient lies in the tunnel formed in this cylinder. This magnet is 1000 times more powerful than the magnetic field of the earth. The power of the machine is determined through a measuring unit called Tesla. Normally the machine is configured as 0.2T, 0.3T, 0.5T, LOT and 1.5T. As the Tesla (power) increases, the accuracy, speed and minuteness of the machine also increase. Superior quality of machines use Helium gas to maintain the magnetic field and therefore the MRI machine has to be placed in an air-conditioned room. Like C T Scan, MRI can also be used for the examination of organs ranging from the brain to spinal cord, stomach, kidney, lungs, bones, muscles etc. The patient is positioned in such a way that the organ to be examined remains at the centre of the machine. Here the X-Rays are not used, instead radio frequency waves and strong magnetic field are used, this eliminates the fear of ha...