Who discovered x-rays?
Wilhelm Conrad Roentgen
What are the primary components of a dental x-ray machine?
1. the tubehead
2. an extension arm
3. the control panel
What is the negative electrode inside the x-ray tube?
cathode
What is the positive electrode inside the x-ray tube?
anode
What is usually found on the control panel?
1. master switch
2. an indicator light
3. selector buttons
4. an exposure button.
What are the 3 types of radiation?
1. primary radiation = useful beam
2. secondary radiation = not useful, less penetrating
3. scatter radiation = dangerous
What does the term radiolucent mean?
Permitting the passage of radiant energy, such as x-rays, with little attenuation, the representative areas appearing dark on the exposed film.
What does the term radiopaque mean?
Not allowing the passage of x-rays or other radiation; appears white on exposed film.
What exposure factors control contrast?
kVp = Higher kilovoltage produces more penetrating radiographs and lower radiographic contrast.
What is meant by density?
Density is the overall blackness or darkness of a film. Film blackening (the amount of light transmitted through film).Milliampere controls density.
What is milliampere?
The electron current flowing across the x-ray tube from the cathode to anode. Milliampere controls density.
What is kilovoltage?
A unit of electrical potential difference equals to 1000 volts.
What is the process resulting in the harmful effects of x-rays?
ionization
What is the time period between x-ray exposure and the appearance of symptoms?
Latent Period
What is meant by genetic effects?
Effects of radiation that are passed on to future generations through genetic cells.
What are the two sets of systems of radiation measurement?
1. The older system is referred to as the traditional system or standard system.
2. The newer system is the metric equivalent known as the Systeme Internationale (SI).
What is the maximum permissible does of radiation for occupational exposed persons?
5.0 rems/year
What is the purpose of the collimator? How thick for safety of machine?
To restrict the size and shape of the X-ray beam to reduce patient exposure, may have a round or a rectangular opening.
2.5 mm thick.
What is the purpose of the aluminum filter? How thick for safety of machine?
The purpose of the aluminum filter is to remove the low-energy, long-wavelength, least penetrating x-rays from the beam. X-ray machines operating at 70 kVp or greater must have aluminum filtration of 2.5 mm.
Which patients should wear a lead apron and thyroid collar?
All patients.
What is the most effective measure in reducing a patient's exposure to radiation?
Lead Apron and Thyroid Collar
What is the purpose of personnel monitoring?
To avoid occupational exposure to radiation, so that dental personnel can keep their radiation exposure to zero.
What is the purpose of the equipment monitoring?
Dental x-ray machines must be monitored for leakage radiation, or any radiation (except for the primary beam) that is emitted from the tubehead.
What is the ALARA concept?
The ALARA concept states that all exposure to radiation must be kept to a minimum, or "as low as reasonably achievable.
Tubehead
The part of the x-ray unit that contains the x-ray tube.
Patient protection
Lead Apron &Used to protect major organ and cells
Scatter Radiation
Radiation goes different direction, hence the reason we use patient protection equipment
Primary Radiation
The reaction of radiation with the primary target source being a tooth or a person.
Radiograph
Term we know as x-ray.