Applications of Technique of Examination of The Human Body in the Diagnostic Field/1 – An important technique used to find diseases or pathologies is endoscopy. This word comes from the Greek, endo and skopê which respectively mean “inside” and “look”, so it means “to look inside”. In order to go into the body doctors use a specific instrument called endoscope which consists of a rigid or flexible tube and a light delivery system to illuminate the organ or object under inspection. The light source is normally outside the body and the light is directed by an optical fiber system. Then there is a lens system transmitting the image to the viewer from the fiberscope and an additional channel to allow the entry of medical instruments.
This instruments comes from an evolution of two hundred years: the first endoscope was used in 1822 by William Beaumont; but his investigations were not satisfactory due to the fact that he hardly saw anything because the source of light he used was not strong enough since it was outside the body. Moreover, the tube was very rigid so patiences were forced to assume uncomfortable positions. Despite the tube inflexibility scientist found a way to investigate the stomach, the rectum and bronchi: the turning point was the discovery of optical fiber in 1950 which permitted to build a flexible endoscope and later to have a source of light inside the body situated on the edge of the tube in the lens system.
Nowadays endoscopy is used on a large scale because it allows to diagnose small tumor or polyps and to remove them at the same time. As a matter of fact, people who are older than 50 years have to take colonoscopy preventively to beseech this eventuality. The exam is quite tiresome but a little anesthesia permits to feel no pain. There is another type of endoscopy called laparoscopy, a surgery branch. This technique consists of doing little holes in which doctors introduce their instruments to operate on. Usually it is used when it is necessary to remove big tumors, appendix, gall bladder or hernia. These operations are so difficult that only very expert surgeons are able to do them.
The most fascinating aspect of endoscopy is that the whole body can be observed; indeed it can involve: the gastrointestinal tract, esophagus, stomach and duodenum, small intestine, colon, bile duct rectum and anus, the respiratory tract, the nose, the ear, the urinary tract, the female reproductive system, the cervix, the uterus, the fallopian tubes, the abdominal or pelvic cavity and organs of the chest.
(DI Giacomo Chieregato & Luca Casati- Classe IV – Liceo Scientifico Pier Giorgio Frassati)
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Applications of Technique of Examination of The Human Body in the Diagnostic Field/2 – Nowadays the most used techniques to look inside the human body are two: CT and MR. These high level technologies use different kinds of methods to achieve their goal, which is to give internal images of the human body, and are in constant update. Both these techniques follow the same path to obtain images; first there’s giving of energy to the patient, than this energy has an interaction with the matter that is read by a detector system, which finally gives the required image to the observer.
The source of energy is different between CT (computed tomography) and MR ( magnetic resonance); the first system is based on x-rays, a kind of electromagnetic radiations which are ionizing and quite penetrant. The process consists of sending a beam of photons with a definite amount of energy; then, passing through the body, the beam reaches the exposed plate and the detector system is able to convert the different amount of photons into different colours which create the image. This technique involves some risks because x-rays can break molecular bonds in the human body cells; for this reason it’s not wealthy to undergo too many CT procedures.
On other hand, the MR technique uses a harmless kind of radiations, the RF (radio frequency) waves. Although this process doesn’t involve any risks, it takes much more time than CT to obtain the image. As a matter of fact, in cases of emergency, Ct is used instead of MR despite the fact that MR technique gives higher definition images. The MR process takes advantage of the composition of the human body, which is made of water by 80 %, which contains hydrogen.
As a matter of fact MR uses a magnetic field, inside which the patient is put, which changes the orientation of the hydrogen protons, each one with a characteristic rotation (“spin”). At this point a coil sends a radio-electric pulse which is able to modify another time the orientation of the hydrogen protons; then the spring is turned off and there’s a relaxation of each proton which releases a different amount of energy. When this energy reaches the receiver coil, it is able to create the image with different colours according to the different amount of energy that is transported by the coil.
( Di Marco Frangi e Tommaso Zanchettin – Classi 3a e 4a Liceo Frassati, Seveso)
