X-rays were discovered by the German physicist Wilhelm Konrad Rontgen in November 1895. He called the 'new kind of rays,X-rays, X for the unknown. With these new rays, he could make a photograph of his wife's hand- showing the bones and her wedding ring.Soon afterwards their usefulness to visualize the internal anatomy of humans was established. Today, imaging with X-ray is perhaps the most commonly used diagnostics tool with the medical profession, and the techniques from a simple chest radiography to a digital subtraction angiography or computer tomography depends on the use of X-rays.
BASIS OF DIAGNOSIS RADIOLOGY
A radiological examination is one of the most important diagnostic aids available in the medical practice. It is based on the fact that various anatomical structures of the body have different densitiesfor the X-rays. When X-rays from a point source penetrate a section of the body, the Internal body structures absorb varying amount of radiation. The radiation that leaves the body has a spatial intensity variation,i.e. an image of the internal structure of the body. The commonly used arrangement for diagnostic radiology. The X-ray intensity distribution is visualized by a suitable device like a photographic film. A shadow image is generated that corresponds to the X-ray density of the organs in the body section. The examination technique varies according to the clinical problem. The main properties of X-rays, which make them suitable for the purpose of medical diagnosis, are their:
Chest radiography is mainly taken for examination of the lungs and the heart. Because of the air enclosed in the respiratory tract, the larger bronchi are seen as a negative contrast, that the pulmonary vessels are seen as a positive contrast against the air- filled lung tissue. Different types of lung infections are accompanied by characteristics changes, which often enable a diagnosis to be made from the location, size and extent of the shadow.
Heart examination are performed by taking frontal and lateral films. The evaluation is perfomed partly by calculating the total heart volume and partly on the basis of any changes in shape. For visualization of the rest of the circulatory system and for the special examination of the heart, use is made of injectible , water-soluble orgainic compound of iodine. A contrast medium is injected into an artery or vein, usually through a catheter placed in the vessels. Therefore, all the larger organs of the body can be examined by visualizing the associated vessels and this techniques is called angiography. The examination is designed according to the organ examined - e.g. for corona ry angiography- the coronary vessels of the heart-, angiocardiography- the heart , and cerebral angiography-, the brain.
The entire gastro-intestinal tract can be imaged by using an emulsion of barium sulphate as a contract medium. It is swallowed or administered to diagnose common pathological conditions such as ulcers, tumors or inflammatory conditions. Negative and positive contrast media are used for visualizing the spinal canal, the examination being known as myethology. The central nervous system is usually examined by pneumography,i.e, filling the body cavities with air. It may, however, be mentioned that computerized tomography has greatly reduced the need for some of the invasive neuro-radiological methods,which involve discomfort and a certain risk for the patient.
BASIS OF DIAGNOSIS RADIOLOGY
A radiological examination is one of the most important diagnostic aids available in the medical practice. It is based on the fact that various anatomical structures of the body have different densitiesfor the X-rays. When X-rays from a point source penetrate a section of the body, the Internal body structures absorb varying amount of radiation. The radiation that leaves the body has a spatial intensity variation,i.e. an image of the internal structure of the body. The commonly used arrangement for diagnostic radiology. The X-ray intensity distribution is visualized by a suitable device like a photographic film. A shadow image is generated that corresponds to the X-ray density of the organs in the body section. The examination technique varies according to the clinical problem. The main properties of X-rays, which make them suitable for the purpose of medical diagnosis, are their:
- Capability to penetrate matter coupled with differential absorption observed in various materials; and
- Ability to produce luminescence and its effect on photographic emulsions.
Chest radiography is mainly taken for examination of the lungs and the heart. Because of the air enclosed in the respiratory tract, the larger bronchi are seen as a negative contrast, that the pulmonary vessels are seen as a positive contrast against the air- filled lung tissue. Different types of lung infections are accompanied by characteristics changes, which often enable a diagnosis to be made from the location, size and extent of the shadow.
Heart examination are performed by taking frontal and lateral films. The evaluation is perfomed partly by calculating the total heart volume and partly on the basis of any changes in shape. For visualization of the rest of the circulatory system and for the special examination of the heart, use is made of injectible , water-soluble orgainic compound of iodine. A contrast medium is injected into an artery or vein, usually through a catheter placed in the vessels. Therefore, all the larger organs of the body can be examined by visualizing the associated vessels and this techniques is called angiography. The examination is designed according to the organ examined - e.g. for corona ry angiography- the coronary vessels of the heart-, angiocardiography- the heart , and cerebral angiography-, the brain.
The entire gastro-intestinal tract can be imaged by using an emulsion of barium sulphate as a contract medium. It is swallowed or administered to diagnose common pathological conditions such as ulcers, tumors or inflammatory conditions. Negative and positive contrast media are used for visualizing the spinal canal, the examination being known as myethology. The central nervous system is usually examined by pneumography,i.e, filling the body cavities with air. It may, however, be mentioned that computerized tomography has greatly reduced the need for some of the invasive neuro-radiological methods,which involve discomfort and a certain risk for the patient.
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