An X-Ray machine consists of two main components – X-Ray generator and an image detection system. An X-Ray tube essentially is a high-vacuum diode consisting of a Cathode and Anode. X-ray tube operates by generating a stream of electrons by heating up a cathode (tungsten) filament.An X-Ray machine consists of two main components – X-Ray generator and an image detection system. An X-Ray tube essentially is a high-vacuum diode consisting of a Cathode and Anode. X-ray tube operates by generating a stream of electrons by heating up a cathode (tungsten) filament.The positively charged anode is the target of electrons released from the cathode. Most of the electrons that strike the anode deposit their kinetic energy, generated by the applied tube voltage and current, as heat. Only a small fraction go on to produce X-rays. As a result, a significant amount of heat is generated at the anode in the production of diagnostic images. Stationary anodes were used in the past. However, the small focal spot on a stationary anode limits the number of X-rays that can be produced without damaging the anode. Therefore, most X-ray machines today use a rotating anode. This allows for the spread of heat over a larger area, which allows for greater tube currents and exposure durations. The rotating anode is a disk mounted on a bearing supported rotor assembly. The rotor consists of a center iron cylinder with surrounding copper bars. The stator device is made of electromagnets that surround the rotor. When an alternating current passes through the electromagnets of the stator, it produces a rotating magnetic field. This field produces an electrical current in the rotor's copper bars, which, in turn, creates an opposing magnetic field to the one induced by the stator—the results in the rotation of the rotor device. Rotation speeds of up to 10,000 revolutions per minute can be produced.The cathode, anode, rotor apparatus, and the other associated structures are collectively called the X-ray tube insert. They are all contained in a glass or metal enclosure and sealed under a high vacuum. This enclosure is known as the envelope. X-ray photons emitted from the focal spot scatter in all directions. The use of a tube port helps form a useful beam.
The X-ray tube housing provides shielding and cooling of the X-ray tube insert. Typically, between the insert and the housing is a layer of oil that provides heat conduction and electrical insulation. A lead shield is also applied to the inside of the housing to attenuate X-rays that are not directed to the tube port. However, not all X-rays are blocked, and the fraction that penetrates the housing is known as leakage radiation. Each tube housing has a maximum tube potential that should not be exceeded during operation at the risk of an unacceptable amount of leakage radiation. As the X-rays come out of the tube port, the size and shape of the X-ray field can be adjusted by collimators. The collimator housing attaches to the tube p
2. • X-ray has three main components:
• Operating Console
• High Frequency Generator
• X-ray Tube
• Internal
• External
Other Parts include
• Collimator and Grid
• Bucky
• X-ray Film
3. • The operating console allows the radiologic technologist to
control the x-ray tube current and voltage so that the useful x-
ray beam is of proper quantity and quality.
• Radiation quantity refers to the number of x-rays or the
intensity of the x-ray beam.
• Radiation quantity is usually expressed in milliroentgens (mR)
or milliroentgens/milliampere-second (mR/mAs).
• The operating console usually provides for control of line
compensation, kVp, mA, and exposure time. Meters are
provided for monitoring kVp, mA, and exposure time.
4. • A high frequency generator powers the X-ray tube.
Earlier, high voltage generators were used.
• High frequency generators are used for X-ray because
they operate on single phase and give less voltage
ripples.
• Another reason for using is its small size, which makes it
portable.
5. • The X-ray tube can be classified as
• Internal
• External
• External
• The external part includes:
• Tube Support
• Protective Housing
• Glass or Metal Envelope
6. • Internal
• The internal parts include
• Cathode : The filament that causes thermionic emission
• Anode: A flat disc made of tungsten that draws the electrons
across the tube
• The inside of the tube is vacuumed so that the X-rays are
produced isotropic ally.
Cathode
Anode
X-rays
8. • Collimator is a device used to minimize the field of view,
avoid unnecessary exposure using lead plates. Lead
shutter are used to restrict the beam. The collimator is
attached to the X-ray below the glass window where the
useful beams is emitted.
• Grid is similar to a collimator except they have different
positions. Grid is placed right after the patient. It is made
up of lead strips, which is used to eliminated scattered
light. These strips only allow rays at 90º to pass through.
•
9. • It is film that is placed after the bucky. It turns black when
X-rays interact with it and stays white where the X-rays
are absorbed. This causes an image to be formed that is
in black, grays and white.
10. • The uses of x rays in the fields of medicine
and dentistry have been extremely important. Examples
might include the observation of the broken bones and
torn ligaments of football players, the detection of
breast cancer in women, or the discovery of cavities and
impacted wisdom teeth.
• Since x rays can be produced with energies sufficient to
ionize the atoms making up human tissue, it can be used
to kill these cells.
