X-ray report Avce Science
INTRODUCTION 1
DISCOVERY OF X-RAYS 2
PRODUCTION OF X-RAYS 3
PRODUCTION OF X-RAYS IN MORE DETAIL 3
THE USES OF X-RAYS 4
TECHNIQUE 6
RISKS & COMPLICATIONS 6
Introduction
X-ray is a form of electromagnetic radiation, in the wavelength range of 10-11 to 10-9m.
X-ray is produced when a beam of high-energy electron strike a metal object anode E.g. Copper within an evacuated tube.
X-ray photographs are produced when the rays pass through a specimen and on to a photographic plate (imager).
It's a short wavelength and can penetrate inner tissues in the human body, which can produce images of the internal body.
X-ray photography is used for diagnosing disease and the x radiation can also treat cancer.
It can reveal abnormalities in the human body such as fractures, infections, and presence of foreign body.
E.g. Bullets or needles.
Discovery of X-rays
On 8 November 1895 German born physicist Wilhelm Röntgen discovered x-rays by mistake.
This helped shape the ideas of using x-rays for medical diagnoses and cancer treatment.
He was investigating the consequence of electricity discharged through gases at small pressures to generate a beam of cathode rays (or electrons).
He used a vacuum tube invented by British Chemist and Physicist William Crookes.
He concentrated a narrow beam of rays from the tube which was roofed in cardboard onto a screen in a dark room and noticed a dim light on a near bench, caused by fluorescence from a different screen.
Röntgen knew that cathode rays could only travel about a few centimetres and the board was placed a metre away, which means this wasn't cathode ray.
Because he didn't know what the rays were he called them X-rays.
He took the first X-ray photograph of his wife's hands.
The properties of X-rays are:
* They're formed on the walls of discharge tube by cathode rays.
* Like light, they move in straight lines and cast shadows.
* Most bodies are transparent to them.
* In some extent they can blacken photographic plates and cause some substances to fluoresce.
* Dissimilar to cathode rays they are not deflected by magnetic fields.
Unfortunately Röntgen didn't know the dangers of his own discovery; he didn't know what long-term exposure to X radiation could cause.
The outcome for Röntgen ...
This is a preview of the whole essay
The properties of X-rays are:
* They're formed on the walls of discharge tube by cathode rays.
* Like light, they move in straight lines and cast shadows.
* Most bodies are transparent to them.
* In some extent they can blacken photographic plates and cause some substances to fluoresce.
* Dissimilar to cathode rays they are not deflected by magnetic fields.
Unfortunately Röntgen didn't know the dangers of his own discovery; he didn't know what long-term exposure to X radiation could cause.
The outcome for Röntgen and his assistant was radiation poisoning.
This is because they were exposed to X-rays regularly and that built up a critical amount of radiation in their bodies.
Nowadays x-ray is used for diagnosing diseases and fighting cancer.
The advantages of x-ray are:
* Cheap and easy to use (one image costs £150-£300 opposed to MRI Magnetic Resonance Imaging which is about £300-£400 per image)
* X-ray machines are mobile and can be transported through Vans on tour.
* You can get clear imaging on bones perfect for fractures.
* Quick results (it takes about half an hour to produce an image)
The disadvantages of x-ray are:
* Poor images produced on soft tissue.
* Causes ionisation of molecules in living cells in living organisms and can cause cancer.
* Barium meals, which are used to improve the image of the internal body, are quite harmful and unpleasant.
* The more you are exposed to x-rays the harmful it gets.
* X-rays need a high power supply (several thousand vaults) so great care needs to be taken when using the machine.
Production of x-rays
X rays are electromagnetic radiation ranging in wavelength from about 100 A to 0.01 A (1 A is equivalent to about 10-8 cm/about 4 billionths of an inch.) The shorter the wavelength of the X ray, the larger its energy and its penetrating power.
Longer wavelengths, close to the ultraviolet-ray band of the electromagnetic spectrum, are recognized as soft X rays.
The shorter wavelengths, nearer to and overlapping the gamma-ray varieties are called hard X rays.
X rays are created when high-velocity electrons hit a material object.
A lot of the energy of the electrons is lost in heat; the remains produces X rays by causing changes in the objects atoms as a consequence of the collision.
The X rays emitted can have no further energy than the kinetic energy of the electrons that create them.
Additionally, the emitted radiation is not monochromatic (composed of radiation of one wavelength) but is composed of an open range of wavelengths among a sharp, lower wavelength limit equivalent to the greatest energy of the bombarding electrons.
This sort of nonstop spectrum is referred to by the German name bremsstrahlung, which means "braking," or slowing down, radiation, and is self-determining of the nature of the target.
A fast-moving electron colliding against the target can have two effects: It can excite X rays of any energy up to its own energy; or it can excite X rays of particular energies, reliant on the nature of the target atom.
Production of x-rays in more detail
To explain x-rays production in more detail, a voltage of 100kv is placed across electrodes inside an evacuated tube.
The negative electron (cathode) is then heated up by the electric current passing through, its then when electrons are emitted.
These electrons are then accelerated by high voltage to hit a positive electrode (anode).
These electrons strike an anode; most of their energy is transferred as thermal. The rest of the energy forms x-ray emissions.
Depending on the voltage the more x-rays get emitted.
If the voltage is high you would expect to get more x-ray emissions.
The equation to describe this is: E= hf
H=6.63*10-34Js.
As the energy increases so does the frequency of the x-rays but the wavelength decreases.
The production of x-rays for diagnoses, the voltage across the electrodes is held between 80-120Kv.
For cancer treatment a voltage greater than 200Kv is used.
The uses of X-rays
X-ray photographs, called radiographs, and fluoroscopy are used widely in medicine as diagnostic tools. In radiotherapy, X rays are used to treat certain diseases, mostly cancer, by exposing tumours to X radiation.
The use of radiographs for diagnostic purposes was natural in the penetrating properties of X rays.
Within a few years of their discovery, X rays were being used to locate foreign bodies, such as bullets, within the human body.
Radiographs revealed differences in tissues, and many pathological conditions could be diagnosed by means of X rays.
X rays provided the most vital single technique of diagnosing tuberculosis when that disease was rampant.
Pictures of the lungs were easy to annotate because the air spaces are more see-through to X rays than the lung tissues.
The latest X-ray device, used with no dyes, produces clear images of any part of the anatomy, including soft organ tissues. Called the body scanner it rotates 180° around a patient's body, distributing out a pencil-thin X-ray beam at 160 different points.
Crystals placed at the differing points of the beam pick up and record the absorption rates of the varying thicknesses of tissue and bone. These data are then transmitted onto a computer that turns the information into an image on a screen.
Technique
A basic X-Ray (radiograph) is an image created after X-Rays have passed all the way through a part of the body e.g. chest.
The image is formed on a recording medium like the X-Ray film underneath the bed the patient lies on. This happens by the interaction of X-Rays with the silver particles present, a bit like the process of taking a photograph.
In this procedure, the image is developed in a black and white picture of the area that we wanted to produce an image of.
This is how you would take an x-ray image:
The Patient is positioned with the suitable part of the body we want to produce an image of, on or close to the X-Ray film.
X-Rays are produced from an X-Ray tube and focussed at the X-Ray film.
Normally there is little or no preparation required.
There is no sensitivity or pain caused by performing the test except if the part being examined is painful like with a fracture or with broken bone.
Risks & Complications
There are no instant hazards after performing a plain X-ray. This is because X-Rays are a form of high-energy radiation, repetitive and extreme exposure of body tissues to this radiation will eventually cause damage to the patient.
This includes:
* Cancer
* Ionisation of cells
* Damaged tissues
* Leukaemia and sterility
Nonetheless the standard quantity of radiation produced throughout one basic X-Ray is much less then the background radiation we receive from the atmosphere.
On the other hand all effort is made to avoid contact with pregnant women. This is because X-Rays can have harmful effects on the foetus. This can be really harmful by causing abnormalities.
