The rays are part of the electro-magnetic spectrum; their wavelengths are between 10?9 and 10? 13 metres; in behaviour and energy they are identical to the gamma rays emitted by radioactive isotopes. Diagnostic X-rays are generated in an evacuated tube containing an anode and cathode. Electrons striking the anode cause emission of X-rays of varying energy; the energy is largely dependent on the potential di?erence (kilovoltage) between anode and cathode. The altered tissue penetration at di?erent kilovoltages is used in radiographing di?erent regions, for example in breast radiography (25–40 kV) or chest radiography (120–150 kV). Most diagnostic examinations use kilovoltages between 60 and 120. The energy of X-rays enables them to pass through body tissues unless they make contact with the constituent atoms. Tissue attenuation varies with atomic structure, so that air-containing organs such as the lung o?er little attenuation, while material such as bone, with abundant calcium, will absorb the majority of incident X-rays. This results in an emerging X-ray pattern which corresponds to the structures in the region examined.
Radiography The recording of the resulting images is achieved in several ways, mostly depending on the use of materials which ?uoresce in response to X-rays. CONTRAST X-RAYS Many body organs are not shown by simple X-ray studies. This led to the development of contrast materials which make particular organs or structures wholly or partly opaque to X-rays. Thus, barium-sulphate preparations are largely used for examining the gastrointestinal tract: for example, barium swallow, barium meal, barium follow-through (or enteroclysis) and barium enema. Water-soluble iodine-containing contrast agents that ionise in solution have been developed for a range of other studies.
More recently a series of improved contrast molecules, chie?y non-ionising, has been developed, with fewer side-effects. They can, for example, safely be introduced into the spinal theca for myeloradiculography – contrast X-rays of the spinal cord. Using these agents, it is possible to show many organs and structures mostly by direct introduction, for example via a catheter (see CATHETERS). In urography, however, contrast medium injected intravenously is excreted by the kidneys which are outlined, together with ureters and bladder. A number of other more specialised contrast agents exist: for example, for cholecystography – radiological assessment of the gall-bladder. The use of contrast and the attendant techniques has greatly widened the range of radiology. IMAGE INTENSIFICATION The relative insensitivity of ?uorescent materials when used for observation of moving organs – for example, the oesophagus – has been overcome by the use of image intensi?cation. A faint ?uorographic image produced by X-rays leads to electron emission from a photo-cathode. By applying a high potential di?erence, the electrons are accelerated across an evacuated tube and are focused on to a small ?uorescent screen, giving a bright image. This is viewed by a TV camera and the image shown on a monitor and sometimes recorded on videotape or cine. TOMOGRAPHY X-ray images are two-dimensional representations of three-dimensional objects. Tomography (Greek tomos
– a slice) began with X-ray imaging produced by the linked movement of the X-ray tube and the cassette pivoting about a selected plane in the body: over- and underlying structures are blurred out, giving a more detailed image of a particular plane.
In 1975 Godfrey Houns?eld introduced COMPUTED TOMOGRAPHY (CT). This involves
(i) movement of an X-ray tube around the patient, with a narrow fan beam of X-rays; (ii) the corresponding use of sensitive detectors on the opposite side of the patient; (iii) computer analysis of the detector readings at each point on the rotation, with calculation of relative tissue attenuation at each point in the cross-sectional plant. This invention has enormously increased the ability to discriminate tissue composition, even without the use of contrast.
The tomographic e?ect – imaging of a particular plane – is achieved in many of the newer forms of imaging: ULTRASOUND, magnetic resonance imaging (see MRI) and some forms of nuclear medicine, in particular positron emission tomography (PET SCANNING). An alternative term for the production of images of a given plane is cross-sectional imaging.
While the production of X-ray and other images has been largely the responsibility of radiographers, the interpretation has been principally carried out by specialist doctors called radiologists. In addition they, and interested clinicians, have developed a number of procedures, such as arteriography (see ANGIOGRAPHY), which involve manipulative access for imaging – for example, selective coronary or renal arteriography.
The use of X-rays, ultrasound or computerised tomography to control the direction and position of needles has made possible guided biopsies (see BIOPSY) – for example, of pancreatic, pulmonary or bony lesions – and therapeutic procedures such as drainage of obstructed kidneys (percutaneous nephrostomy), or of abscesses. From these has grown a whole series of therapeutic procedures such as ANGIOPLASTY, STENT insertion and renal-stone track formation. This ?eld of interventional radiology has close a?nities with MINIMALLY INVASIVE SURGERY (MIS).
Radiotherapy, or treatment by X-rays The two chief sources of the ionising radiations used in radiotherapy are the gamma rays of RADIUM and the penetrating X-rays generated by apparatus working at various voltages. For super?cial lesions, energies of around 40 kilovolts are used; but for deep-seated conditions, such as cancer of the internal organs, much higher voltages are required. X-ray machines are now in use which work at two million volts. Even higher voltages are now available through the development of the linear accelerator, which makes use of the frequency magnetron which is the basis of radar. The linear accelerator receives its name from the fact that it accelerates a beam of electrons down a straight tube, 3 metres in length, and in this process a voltage of eight million is attained. The use of these very high voltages has led to the development of a highly specialised technique which has been devised for the treatment of cancer and like diseases.
Protective measures are routinely taken to ensure that the patient’s normal tissue is not damaged during radiotherapy. The operators too have to take special precautions, including limits on the time they can work with the equipment in any one period of time.
The greatest value of radiotherapy is in the treatment of malignant disease. In many patients it can be used for the treatment of malignant growths which are not accessible to surgery, whilst in others it is used in conjunction with surgery and chemotherapy.... x-rays
Symptoms: sweat rash, photophobia (intolerance of bright light on the iris of the eye), wasting, rapid heart beat, weakness, swollen ankles, diminished reflexes.
Alternatives. Assist the liver in its task to eliminate poisons, and to cleanse the lymph system.
Adults: Gotu Kola, Sarsaparilla, German Chamomile: teas.
Young children: German Chamomile tea: sips, freely – as much as well tolerated. ... acrodynia
Mercury has an affinity for the central nervous system. Soon it concentrates in the kidney causing tubular damage. A common cause is the mercurial content (50 per cent) in the amalgam fillings in teeth which, under certain conditions, release a vapour. Fortunately, its use in dentistry is being superceded by an alternative composite filling.
A common cause of poisoning was demonstrated in 1972 when 6,000 people became seriously ill (600 died) from eating bread made from grain treated with a fungicide containing methylmercury. For every fungus in grain there is a mercuric compound to destroy it. The seed of all cereal grain is thus treated to protect its power of germination.
Those who are hypersensitive to the metal should as far as possible avoid button cells used in tape recorders, cassette players, watch and camera mechanisms. As the mercury cells corrode, the metal enters the environment and an unknown fraction is converted by micro organisms to alkylmercury compounds which seep into ground waters and eventually are borne to the sea. When cells are incinerated, the mercury volatilises and enters the atmosphere. (Pharmaceutical Journal, July 28/1984)
Mercury poisoning from inhalation of mercury fumes goes directly to the brain and pituitary gland. Autopsies carried out on dentists reveal high concentrations of mercury in the pituitary gland. (The Lancet, 5-27-89,1207 (letter))
Treatment. For years the common antidote was sulphur, and maybe not without reason. When brought into contact sulphur and mercury form an insoluble compound enabling the mercury to be more easily eliminated from the body. Sulphur can be provided by eggs or Garlic.
Old-time backwoods physicians of the North American Medical School used Asafoetida, Guaiacum and Echinacea. German pharmacists once used Bugleweed and Yellow Dock. Dr J. Clarke, USA physician recommends Sarsaparilla to facilitate breakdown and expulsion from the body.
Reconstructed formula. Echinacea 2; Sarsaparilla 1; Guaiacum quarter; Asafoetida quarter; Liquorice quarter. Dose: Liquid Extracts: 1 teaspoon. Tinctures: 2 teaspoons. Powders: 500mg (two 00 capsules or one-third teaspoon). Thrice daily.
Chelation therapy.
Formula. Tinctures. Skullcap 2-15 drops; Pleurisy root 20-45 drops; Horehound 5-40 drops. Mercurial salivation. Thrice daily. (Indian Herbology of North America, by Alma Hutchens) Dental fillings: replace amalgam with safe alternative – ceramic, etc. Evidence of a link between tooth fillings containing mercury and ME has caused the use of dental amalgam to be banned in Sweden. ... mercury poisoning
Many sufferers make use of a radio, television, cassette player, or headphones to block out the noise in their ears.
A tinnitus masker, a hearingaid type device that plays white noise (a random mixture of sounds at a wide range of frequencies), may be effective.... tinnitus
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