Chapters 3-4: Radiation Biology & Radiation Protection Flashcards
Radiation Injury, Radiation Protection, Radiation Safety
Define the term: ionizing radiation
radiation capable of producing ions
Which theory of radiation injury is the least likely to occur in dental imaging?
direct theory
What are stochastic effects of radiation?
- biologic effects of radiation that occur as a direct function of dose
- the probability of occurence increases with increasing absorbed dose; however, the severity of effects does not depend on the magnitude of absorbed dose
Define the term: free radical
an uncharged, neutral atom or molecule that exists with a dingle, unpaired electron in its outermost shell
Define the term: image receptor
a recording medium (ex: PSP plates or digital sensors)
How is the response of a cell to radiation exposure determined?
- mitotic activity
- cell differentiation
- cell metabolism
Define the term: somatic cells
all cells in the body, with the exception of reproductive cells
Which type of radiation effect is not applicable in dentistry?
short-term effects
Define the term: diagnostic image
a dental image that allows for the identifying and monitoring of diseases or injuries
Cataract formation, decreased fertility and radiation sickness are all examples of whihc type of radiation effect?
nonstochastic effects
What is the ALARA concept?
a concept of radiation protection that states all exposure to radiation must be kept to a minimum, or “as low as reasonably achievable”
Define the term: sievert (Sv)
a unit of measurement for dose equivalent
Define the term: genetic effects
effects of radiation that are not seen in the person irradiated but are passed on to future generations through genetic cells
Define the term: coulomb (C)
- a unit of electrical charge
- the quantity of electrical charge transferred by 1 ampere in 1 second
List the two types of radiation effects on human tissue.
- stochastic effects
- nonstochastic effects
What are nonstochastic effects of radiation?
effects of radiation that have a threshold and increase in severity with increasing absorbed dose
Define the term: critical organ
an organ that, if damaged, diminishes the quality of an individual’s life
What determines the length of the latent period in radiation injury?
the total dose of radiation or the rate/total time of radiation
Define the term: maximum permissible dose (MPD)
the maximum dose equivalent that a body is permitted to receive within a specific period of time
What is the greatest source of background radiation in the United States?
radon gas in the soil
Define the term: cell differentiation
the individual characteristics of a cell that determine the response of a cell to radiation exposure
Define the term: cumulative occupational dose
the accumulated occupational dose for occupationally-exposed workers
Define the term: somatic effects
radiation injuries that produce changes in somatic cells and produce poor health in the irradiated individual
What are the three quantiites of measurement in radiation?
- exposure
- dose
- dose equivalent
After exposure, what are the next steps in radiation injury?
- latent period
- period of injury
- recovery period
What is medical radiation?
radiation exposure for medical diagnosis and treament
How can your imaging technique affect the patient’s exposure and dose?
using the paralleling technique and increasing the target-receptor distance reduces the dose
Define the term: imaging technique
the style and process of exposing image receptors (ex: paralleling, bisecting, panoramic)
What is the most common example of a protective barrier in a dental office?
a wall
If leaving the room during exposure is not possible, how must the dental radiographer stand in relation to the primary beam?
at least 6 feet away from the x-ray tubehead, at a perpendicular angle to the primary beam
What is artificial/human-made radiation?
radiation caused by modern technology
Define the term: dose
the amount of energy absorbed by a tissue
Birth abnormalities and genetic defects are examples of which type of radiation effect?
long-term effects
Define the term: non-diagnostic image
an image that has undergone exposure or technique errors that cannot be used in the proper diagnosis of disease or injuries, and must be retaken