Radiology E1 Flashcards
(25 cards)
Which of the magnetic radiations have greater energy levels than X-rays?
Gamma
What type of force carrier particles make up the X-ray beam?
Photons
The quantum theory of radiation has been successful in correlating experimental data on ______________.
The production of X-Rays
Within the X-ray tube, electrons stream from the filament of the ________ to __________.
Cathode (-) to Anode (+)
What percentage of the kinetic energy of electrons that hit the anode are converted to heat?
99%
What is the primary source of radiation from the X-ray tube?
Bremsstrahlung
What happens if the kVP is increased?
An increase in kVP will….
INCREASE Maximal energy
INCREASE Photons generated
INCREASE Mean energy
What type of photon scattering is most common in an X-Ray beam?
The highest percentage is Compton Scattering at 57%
Lower energy photons are removed by aluminum filtration, so what happens to the beam?
X-Ray beams Mean Energy INCREASES and the Beam Intensity DECREASES.
In Deterministic effects, related to a certain threshold, above which you will see this effect and below this threshold you will not is known as _________.
Stochastic threshold –> no threshold –> smallest amount can lead to carcinogenic effects.
Expl. of this is Sunburn from prolonged exposure to sunlight.
What types of tissues are more susceptible to radio sensitivity?
Rapidly dividing cells such as Basal cells in the oral mucosa.
Fibroblast, neurons, kidney, striated muscle are not as easily affected because they do not divide
Which is true about radiation therapy in the jaw of children?
If radiation precedes dental calcification it may destroy the tooth, especially if the child is undergoing chemotherapy.
How soon after a patient completes head and neck radiation therapy should you wait before taking x-rays?
Avoid intraoral radiographs for the first 6 months
Which organs have the lowest susceptibility to radiation?
Salivary glands
What type of radiation from natural sources is the most common in the world’s population?
Radon
Dental X-Rays are responsible for what percentage of human exposure to radiation?
<1%
The average dose of an individual to occupation exposure from operation of equipment is what percentage of the allowable exposure?
Less than 1%
According to the Linear Non-threshold hypothesis, is there any risk of cancer from exposure?
Yes, there is some risk.
According to the principle of Justification, which does more good than harm?
Justification-slight increase in risk for cancer is worth irradiating patients
Which is better for the patient in intraoral film speed?
E and F speed has the same useful contrast as D speed with much less radiation
State regulations require collimated distance from the patient of how much distance?
Round= 7 cm or 2 3/4 " Rectangle= 1/5 of that distance
Lead is located in which layer of x-ray film?
Lead is positioned behind the black paper and film layers.
What size of dental films are used for adult bite wings?
Size 2
When you use a dark room with a Safe Light, how long can the light stay on before it will negatively affect the films?
5 minutes
