Regarding the components of X-ray tube:
A- X-ray tube has a negatively charged cathode and positively charged anode.
B- The cathode contains a filament made of a coiled tungsten wire.
C- The cathode is the source of electrons.
D- The electrons are accelerated towards the anode where X-ray are produced.
E- All of above are true.
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X-rays are a form of electromagnetic radiation made up of photons.
For simplicity, let us equate them with invisible light capable of crossing matter. The more dense the medium will be, the more this radiation will be attenuated. This property conditions the obtaining of the radiological images.
It consists of a filament and two electrodes (the cathode and the anode) confined in a vacuum chamber. When heated, the filament releases electrons.
Under the effect of a potential difference (applied between the two electrodes) the electrons are accelerated towards the anode. This results in high-speed collisions with energy transfer to the anode which restores some of this energy in the form of X-rays.
To the naked eye, the material seems "full". In fact, on the atomic scale there is a certain vacuum (the core-electron distance is equal to 100,000 times the diameter of the nucleus).
This property allows part of the X-ray to pass through a medium without interference of any kind.
X-rays that do not travel in these "free spaces" interact with the material in which they are partially absorbed by transferring some of their energy.
X-rays can be either photo-electrically absorbed or scattered by the Compton effect.
- The photoelectric effect:
An X-ray of sufficient energy will eject an electron from a deep layer. By transferring all its energy to the "runaway" electron, the photon is annihilated. The free space is replaced by an electron with a superficial layer with very low energy X-ray emission. This effect is predominant in dense media for low energy X-radiation.
- The Compton effect:
An X-ray passing near a peripheral electron is deflected and attenuated. The lost energy is transferred as kinetic energy to this electron (predominant effect between 75 kV and 100kV).
The Compton effect is responsible for scattered radiation. This broadcast from the patient represents a danger to the staff and degrades the quality of the image (less broadcast, it reduces the radiation of staff and staff while increasing the quality of the image). Hence the effectiveness of the leaded apron (Pd: Z = 82) to protect itself from the scattered radiation.
BIOLOGICAL EFFECTS:
- At the molecular level:
Ionizing radiation has effects on DNA leading to more or less significant cellular damage. There are two mechanisms of interactions
the direct effect: a radiation triggers an ionization of a DNA atom thus causing a structure modification. Minimal effect with X-rays used in medicine
the indirect effect: the ionization of the water molecules produces free radicals causing recombinations of the DNA molecule
- At the cellular level:
Either the DNA molecule is able to self-repair and there will be no cellular reverberation.
Either she is incapable and this can then lead to mutations within the cell, or even the death of it.
The cells are all the more sensitive because they are not very differentiated and they divide rapidly.
A- X-ray tube has a negatively charged cathode and positively charged anode.
B- The cathode contains a filament made of a coiled tungsten wire.
C- The cathode is the source of electrons.
D- The electrons are accelerated towards the anode where X-ray are produced.
E- All of above are true.
--------------------------
X-rays are a form of electromagnetic radiation made up of photons.
For simplicity, let us equate them with invisible light capable of crossing matter. The more dense the medium will be, the more this radiation will be attenuated. This property conditions the obtaining of the radiological images.
It consists of a filament and two electrodes (the cathode and the anode) confined in a vacuum chamber. When heated, the filament releases electrons.
Under the effect of a potential difference (applied between the two electrodes) the electrons are accelerated towards the anode. This results in high-speed collisions with energy transfer to the anode which restores some of this energy in the form of X-rays.
To the naked eye, the material seems "full". In fact, on the atomic scale there is a certain vacuum (the core-electron distance is equal to 100,000 times the diameter of the nucleus).
This property allows part of the X-ray to pass through a medium without interference of any kind.
X-rays that do not travel in these "free spaces" interact with the material in which they are partially absorbed by transferring some of their energy.
X-rays can be either photo-electrically absorbed or scattered by the Compton effect.
- The photoelectric effect:
An X-ray of sufficient energy will eject an electron from a deep layer. By transferring all its energy to the "runaway" electron, the photon is annihilated. The free space is replaced by an electron with a superficial layer with very low energy X-ray emission. This effect is predominant in dense media for low energy X-radiation.
- The Compton effect:
An X-ray passing near a peripheral electron is deflected and attenuated. The lost energy is transferred as kinetic energy to this electron (predominant effect between 75 kV and 100kV).
The Compton effect is responsible for scattered radiation. This broadcast from the patient represents a danger to the staff and degrades the quality of the image (less broadcast, it reduces the radiation of staff and staff while increasing the quality of the image). Hence the effectiveness of the leaded apron (Pd: Z = 82) to protect itself from the scattered radiation.
BIOLOGICAL EFFECTS:
- At the molecular level:
Ionizing radiation has effects on DNA leading to more or less significant cellular damage. There are two mechanisms of interactions
the direct effect: a radiation triggers an ionization of a DNA atom thus causing a structure modification. Minimal effect with X-rays used in medicine
the indirect effect: the ionization of the water molecules produces free radicals causing recombinations of the DNA molecule
- At the cellular level:
Either the DNA molecule is able to self-repair and there will be no cellular reverberation.
Either she is incapable and this can then lead to mutations within the cell, or even the death of it.
The cells are all the more sensitive because they are not very differentiated and they divide rapidly.
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Anatomy