X-ray Units Flashcards
Tungsten has a ______ atomic number which helps with an efficient production of x-rays.
High
What is amperage?
Number of electrons moving through a circuit
What is voltage?
Electrical force that causes electrons to move from a negative pole to a positive pole.
How does collimation (collimator) filter out photons?
Collimator filters photons out based on specific size and shape of the collimator
How does filtration work in the tube head?
Filtration filters out photons based on wavelength and frequency. Longer wavelength/low energy photons are filtered out only allowing high energy photons to pass through.
Why is tungsten used in the X-ray unit?
It has the highest melting point of all metals in pure form thus it can withstand the high energy and heat that x-rays produce.
It also has a high atomic number (74), which helps with more electrons in the orbitals of the target in the anode.
What are the components of an intraoral x-ray unit?
- Tube head
- Extension arm
- Control panel
Where in the x-ray unit are x-rays produced?
X-rays will be produced in the x-ray tube inside the tube head
What are the components of the x-ray tube?
- Cathode
- Anode
- Evacuated lead glass envelope (with a non-lead glass window)
True or False: The tube head components of the intraoral x-ray unit are similar to the tube head on the extraoral tube head.
True
In the x-ray tube, do electrons flow from the cathode to the anode, or from the anode to the cathode?
Cathode to the Anode
Cathode is the negative pole
Anode is the positive pole
What property of copper makes it a good choice in x-ray equipment?
Copper has very good heat dissipation
What are 2 functions for the insulating oil?
- Heat dissipation/transfer through convection
- Electric insulator
An increase in x-ray quality leads to an increase in ____________?
Mean energy of the x-ray photons in the x-ray beam
Does collimation care about the energy/wavelength of the photons being blocked?
No
What are the 4 aspects of heat dissipation in the tube head?
Heated tungsten block, copper block, insulating oil and the tube metal housing
What amount of kinetic energy dissipates as heat in x-ray production?
99% or more heat
Why do you have to watch the patient when taking an x-ray?
To make sure they don’t move during x-ray exposure
How do you increase the amount of x-rays produced?
- Increase electrical current (mA)
- Increase exposure time
X-rays will be produced when electrons inside the tube start to accelerate and then collide against a target, thus turning the ____ energy of the electrons into x-rays.
Kinetic
What is a position-indicating device (PID)?
A position-indicating device (PID) helps to adjust the direction, focal spot to object distance, and beam shape (cylindrical or rectangular) of the X-Ray.
Also called beam-indicating device (BID) or aiming cylinder
What makes up total filtration?
Inherent filtration and additional filtration
Inherent
* X-ray tube glass
* Insulating oil
Additional
* Aluminum Filter
this is determined by manufacturer
What are the different parts of the control panel?
Exposure button, indicator light, control devices, anatomical regions presets, Child/Adult presets
What is a high-voltage transformer connected to?
cathode and anode
What is a collimator and what does it do?
- Lead disc
- Blocks the more divergent photons
- Collimates the beam area
What does the extension arm of the x-ray unit do?
- connects electrical wires
- aids in horizontal and vertical movements
What is the focusing cup made of?
The focusing cup is made of Molybdenum.
What 3 unit types are there for intra-oral x-ray units?
- fixed on the wall
- mobile stand
- portable/hand-held
What part of the intraoral x-ray unit contributes to inherent filtration?
x-ray tube glass and insulating oil
Is a cathode a positive or negative electrode?
Negative electrode
Are voltage and amperage interchangeable terms?
No. Voltage is the electrical force that causes electrons to move from a negative pole to a positive pole. Amperage is the number of electrons moving through a circuit.
True or False: The Low-Voltage Transformer is connected to the anode only.
False. It is connected to the cathode only.
True or False: Adults and children receive the same amount of radiation when taking X-rays to get a good quality image.
False. There is a button specifically for adult and child presets when taking X-rays. Children should receive less radiation because they are smaller; they need less exposure to get a good quality X-ray image.
What does Insulating Oil do?
Acts as an electrical insulator and helps in heat dissipation
What blocks the more divergent photons?
collimator
What is used as additional filtration in the tube head?
aluminum filter
When the focal spot of an x-ray is decreased and there are less divergent x-rays, what is the result?
increased image sharpness
What were the two examples given of inherent filtration within the tube head?
- X-ray tube glass
- Insulating oil
Regarding the tube head, what is the difference between collimation and filtration?
- Collimation involves physically blocking wavelengths and form a collimated x ray beam.
- Filtration specifically filters out the least energetic wavelengths.
What is mostly generated in the process of producing x-ray photons?
Heat
What is most commonly used in dental units: a stationary anode or a rotating anode?
Stationary anode
What is the purpose of the aluminum filter in the X-ray tube head?
The aluminum filter removes low-energy, less-penetrating X-rays to ensure only the most energetic X-rays are used, reducing patient exposure and improving image quality.
What is the function of the position-indicating device (PID) in an X-ray unit?
The PID directs the X-ray beam, determines the focal spot-to-object distance, and shapes the X-ray beam, typically in cylindrical or rectangular forms.
True or False: the indicator light is on when the x-ray unit has power to it
False - the indicator light is one when the x-ray is being produced.
The ready light is on when the unit has power to it.
