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Urmanova G. U. associate professor Tashkent Pediatric Medical Institute
ROENTGEN COMPUTED TOMOGRAPHY
Annotation: This article illustrates an idea of the nature of research, which is being carried out in the field of physics, and their use in medicine. Actually, physics factors are widely used in almost all areas of medicine, including: diagnostics, treatment, analysis, etc. The methods of roentgen diagnosis and computed tomography, particularly, facilitates the physician's work on accurate and fast diagnostics.
Key words: roentgen, a computed, a tomography, the object for research, a layer, a patient, a scanner and an image, tube, diagnostics.
Hounsfield and Allan Cormack were awarded the Nobel Prize in 1979 for the development of roentgen diagnosis and computed tomography. Their method is based on measuring the difference in roentgen attenuation by tissues of
different density and the complex computer processing. In these days, it is the main tomographic method for examining human internal organs using roentgen.
The tomography (from Greek to^ -the cut, layer and grapho - to write) - is the obtaining a multi-layer image of the internal structure of an object.
Roentgen tomography and its computer methods are interesting and promising areas of radiography. For example, a simple roentgen takes up most of the body, with different organs and tissues casting shadows on each other. To get rid of this shortcoming, it is necessary to periodically move or push the camera roll (CR) together with the roentgen tube (RT) in a phase opposite to the object (Ob) under study (Fig. 1). The body has a number of organs that are opaque to roentgen, which are shown in the figure as circles. As you can see, rays of roentgen at any position of the roentgen tube (1,2, etc.) pass through the same point of the object, which is the center, relative to which the periodic movement of RT and CR occurs. This point, more precisely a small opaque inclusion, is shown by a dark circle. Together with its shadow image, it sequentially occupies 1,2, and so on positions (Fig. 1). and moves. The bones in the body and other organs form the "background" in CR, because they cannot always block the rays of roentgen. By
Fig.1.
changing the position of the center of oscillation, it is possible to obtain a layered roentgen image of the body. After this method, tomography occurred, that is, the recording of a layered image. By using a screen consisting of a thin roentgen pen and a semiconductor ionizing radiation detector instead of CR (a device designed to obtain the digital roentgen images in real time without the use of camera roll), and also for exposure, it is possible to develop a shadow roentgen image in tomography. This state of the art of tomography makes it possible to differentiate a layered image of a body on a cathode ray tube screen or on paper to details less than 2 mm in size (with a roentgen absorption difference of 0.1%). Using this, one can, for example, distinguish between the gray and white matter of the brain, as well as see very small swellings
RCT uses digital geometric data processing to create three-dimensional images of the patient's insides. Three-dimensional (3D) images can be created after many flat two-dimensional (2D) images are taken around a single axis of rotation. In other words, many pictures of the same area ofthe body are taken from different angles, and then they are combined together, which results in a three-dimensional picture (Fig. 2.).
Currently, there are the following methods of tomography:
- Computed tomography (CT) -consists of one roentgen tube rotating around the patient's table. when the tube makes one complete revolution, one image is taken, then the table moves and the scanning step is performed;
- Roentgen computed tomography (RCT) - the rays of roentgen passes through the part of the human body being examined, and the computer "brain" picks up signals from the object and displays them on the screen, that is, a method that reproduces a clear picture of whether the organs of the body are ordered or not, whether there are changes, pathologies, displacements, whether they are enlarged.
- Multi-spiral computed tomography (MSCT) is equipped with two tubes that rotate simultaneously. This type of CT allows you to get clear images of the smallest structures, which is important, for example, in cardiology and cardiac surgery.
- Single-photon emission computed tomography (SPECT) - a type of emission tomography; diagnostic method for creating tomographic images of the distribution of radionuclides.
- Optical coherence tomography is a popular method for studying the tissues of the organs of vision. It allows you to obtain transverse sections of
various structures of the eye (cornea, optic disc, retina, etc.). The diagnostic technology is non-contact and painless.
Now let's look at the differences between the methods that are more commonly known as Roentgen Computer Tomography (RCT) and Magnetic Resonance tomography (MRT).
The main difference between these two most common diagnostic methods is that different types of waves and radiation are used to obtain a three-dimensional image of the object under study.
RCT is characterized by the use of the rays of roentgen, but unlike a roentgen machine that sends out only one of their beams, CT sends a series of thin beams through the human body. Due to the structure of computed tomography, it is possible to obtain a series of images of organs or tissues from different points. The resulting image is then converted into a 3D model.
In MRT, these are powerful magnetic and computer devices that transmit and transform an image based on radio waves. Essentially, MRT measures the water content (or fluid properties) of various tissues. This data is processed by a computer to create a detailed image.
RCT and MRT are the most accurate sources of data for diagnosis and examine:
RCT diagnostics mainly examines the dense tissues of the body:
- diseases of the joints and spine (bone component);
- primary and secondary pathologies of bones of a tumor nature;
- traumatic injuries of the skeleton;
- atherosclerotic changes in blood vessels;
- diseases of the lungs, abdominal organs and pelvic organs (three-phase contrast study), etc.
MRT diagnostics mainly examines the soft tissues of the body:
- changes in muscles, tissues, organs of the abdominal cavity, pelvis, etc.
- the state of the structures of the brain and spinal cord;
- circulatory disorders and injuries of the brain and spinal cord;
- spine, position of joints, etc.
So, we almost know the difference between RCT and MRT. In addition, RCT has a significant radioactive impact, so it cannot be reused. During computed tomography, the rays of roentgen affect organs and tissues for 10 seconds, while for magnetic resonance imaging, for example, while maintaining a stationary position, it may take 10-20 minutes.
RCT or MRT - which is better? Anyone who is concerned about their health wants to go through the most modern and accurate research methods. Despite the differences between RCT and MRT, it is not easy to choose the most effective one, since both methods are valuable for modern medicine. All this depends on a specific goal.
The principle of operation of RCT- If a diagnosis of the lower abdomen is required, for example, tomography of the rectum, then the patient can be given
an irrigoscopy (barium enema). If blood vessels are being examined, then barium is injected into a vein using a specialized injector for injecting contrast agents.
The main advantage of MRT is the ability to obtain an image in any plane (including soft tissue structures). This is a non-invasive method of research with the possibility of conducting without special preparation of the patient. However, MRT is most informative when conducting studies of the spine, brain and spinal cord, retro peritoneal space and abdominal organs, pelvic organs, as well as tissues, joints and blood vessels.
Consequently, the role of roentgens in the flourishing of medicine had an immeasurable impact on dentistry (in 1921, the first roentgen dentistry began to function in Petrograd). For instance, 3D digital roentgen (computed tomography), which is the most modern type of examination in dentistry, which shows the condition of an individual tooth and the entire jaw, as well as pathologies in the muscles of the tooth, etc., while preventing the development of certain diseases.
The improvement of the roentgen apparatus has been widely developed in studies that correspond to the requirements of the times. For example, the World Health Organization allocates funds for the development of modern instrumentation, i.e. for the field of radiology.
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