An X-ray machine is a device that uses X-rays for a variety of applications including medicine, X-ray fluorescence, electronic assembly inspection, and measurement of material thickness in manufacturing operations. In medical applications, X-ray machines are used by radiographers to acquire x-ray images of the internal structures (e.g., bones) of living organisms, and also in sterilization.
Structure
An X-ray generator generally contains an X-ray tube to produce the X-rays. Possibly, radioisotopes can also be used to generate X-rays. An X-ray tube is a simple vacuum tube that contains a cathode, which directs a stream of electrons into a vacuum, and an anode, which collects the electrons and is made of tungsten to evacuate the heat generated by the collision. When the electrons collide with the target, about 1% of the resulting energy is emitted as X-rays, with the remaining 99% released as heat. Due to the high energy of the electrons that reach relativistic speeds, the target is usually made of tungsten even if other material can be used particularly in XRF applications. An X-ray generator also needs to contain a cooling system to cool the anode; many X-ray generators use water or oil recirculating systems.
Medical imaging
In medical imaging applications, an X-ray machine has a control console that is used by a radiologic technologist to select X-ray techniques suitable for the specific exam, a power supply that creates and produces the desired kVp (peak kilovoltage), mA (milliamperes, sometimes referred to as mAs which is actually mA multiplied by the desired exposure length) for the X-ray tube, and the X-ray tube itself.
History The discovery of X-rays came from experimenting with Crookes tubes, an early experimental electrical discharge tube invented by English physicist William Crookes around 1869–1875. In 1895, Wilhelm Röntgen discovered X-rays emanating from Crookes tubes and the many uses for X-rays were immediately apparent. One of the first X-ray photographs was made of the hand of Röntgen's wife. The image displayed both her wedding ring and bones. On January 18, 1896, an X-ray machine was formally displayed by Henry Louis Smith. A fully functioning unit was introduced to the public at the 1904 World's Fair by Clarence Dally. The technology developed quickly: In 1909 Mónico Sánchez Moreno had produced the first portable medical device and during World War I, Marie Curie led the development of X-ray machines mounted in "radiological cars" to provide mobile X-ray services for military field hospitals. In the 1940s and 1950s, X-ray machines were used in stores to help sell footwear. These were known as Shoe-fitting fluoroscopes. However, as the harmful effects of X-ray radiation were properly considered, they finally fell out of use. Shoe-fitting use of the device was first banned by the state of Pennsylvania in 1957. (They were more a clever marketing tool to attract customers, rather than a fitting aid.) Together with Robert J. Van de Graaff, John G. Trump developed one of the first million-volt X-ray generators. By the late 1990s, the manufacturing industry for X-ray machines based on conventional film technology was becoming commoditized. The technology took another leap in the 2000s, as physicists at CERN developed a new way to observe particles - thy hybrid pixel detector. This method is more precise than film radiography, as it converts the energy of each particle into data. The first chip was developed in the 1990s, and in 2010s the technology was made available commercially. It is used in a wide variety of machines, most notably Photon-counting computed tomography.
Description An X-ray imaging system consists of a generator control console where the operator selects desired techniques to obtain a quality readable image (kVp, mA and exposure time), an x-ray generator which controls the x-ray tube current, x-ray tube kilovoltage and x-ray emitting exposure time, an X-ray tube that converts the kilovoltage and mA into actual x-rays and an image detection system which can be either a film (analog technology) or a digital capture system and a PACS.
Applications X-ray machines are used in health care for visualising bone structures, during surgeries (especially orthopedic) to assist surgeons in reattaching broken bones with screws or structural plates, assisting cardiologists in locating blocked arteries and guiding stent placements or performing angioplasties and for other dense tissues such as tumours. Non-medicinal applications include security and material analysis.
Medicine
The main fields in which x-ray machines are used in medicine are radiography, radiotherapy, and fluoroscopic-type procedures.
Radiography
Radiography is generally used for fast, highly penetrating images, and is usually used in areas with a high bone content but can also be used to look for tumors such as with mammography imaging. Some forms of radiography include:
orthopantomogram — a panoramic x-ray of the jaw showing all the teeth at once mammography — x-rays of breast tissue tomography — x-ray imaging in sections X-rays are highly penetrating, ionizing radiation, therefore X-ray machines are used to take pictures of dense tissues such as bones and teeth. This is because bones absorb the radiation more than the less dense soft tissue. X-rays from a source pass through the body and onto a photographic cassette. Areas where radiation is absorbed show up as lighter shades of grey (closer to white). This can be used to diagnose broken or fractured bones.
Radiotherapy
Radiotherapy is the use of x-ray radiation to treat malignant and benign cancer cells. It is a non-imaging application.
Fluoroscopy
Fluoroscopy is used in cases where real-time visualization is necessary (and is most commonly encountered in everyday life at airport security). Some medical applications of fluoroscopy include:
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