Questions And Answers Verified 100% Correct
Which of the following relationships describe the response of tissues to radiation?
- ANSWER -nonlinear, nonthreshold
In dental radiography, biologic damage does occur even though the dose of
radiation is low. A linear relationship indicates that the tissue response is directly
proportional to the dose. A nonthreshold curve states that no matter how small the
dose, some damage does occur. The dose of radiation from dental radiography can
be described as linear, nonthreshold.
Which of the following factors contributes to radiation injury? - ANSWER -total
dose
dose rate
cell sensitivity
age
Identify the correct statement. - ANSWER -long-term effects are seen with small
amounts of radiation
absorbed in a long period.
Short-term effects are seen with large amounts of radiation absorbed in a short
period of time. On the other hand, long-term effects are seen with small amounts of
radiation absorbed over a long period of time.
Radiation injuries that are not seen in the person irradiated but occur in future
generations are termed: - ANSWER -genetic effects
Somatic effects of radiation injury are seen in the irradiated person. Genetic effects
of radiation injury are seen in future generations.
Which of the following is most susceptible to ionizing radiation? - ANSWER -
small lymphocyte
,The response of a cell to radiation exposure depends on the mitotic activity, cell
differentiation, and cell metabolism. Of the choices listed, the small lymphocyte is
the most sensitive to radiation because of its high mitotic activity and metabolism.
The sensitivity of tissues to radiation is determined by: - ANSWER -mitotic
activity
cell differentiation
cell metabolism
Which of the following is considered radioresistant? - ANSWER -mature bone
cells
Of the choices listed, the mature bone cell is the least sensitive to radiation because
of its low mitotic activity and low metabolism rate.
An organ that if damaged diminishes the quality of an individual's life is termed a:
- ANSWER -critical organ
Critical organs are defined as organs of the body that when exposed to radiation
may become damaged and diminish the quality of life. Examples include skin,
thyroid gland, lens of the eye, and bone marrow.
The traditional unit for measuring x-ray exposure in air is termed: - ANSWER -
roentgen
Radiation is measured in the same manner as other physical concepts. The
traditional unit for measuring x-ray exposure in air is termed roentgen; its metric
equivalent is known as the coulomb/kilogram.
The QF is used to determine which of the following radiation units: - ANSWER -
rem
Each type of radiation has a specific quality factor (QF) based on the fact that
different types of radiation produce different types of radiation damage. The QF is
used to determine the product of absorbed dose, or rem.
The unit for measuring the absorption of x-rays is termed: - ANSWER -rad
, Identify the correct conversion. - ANSWER -1 R = 2.58 × 10-4 C
Rationales:
b) 1 rad = 0.01 Gy
c) 1 rem = 0.01 Sv
d) 1 Gy = 100 rads
e) 1 Sv = 100 rems
Which of the following traditional units does not have an SI equivalent? -
ANSWER -roentgen
Which of the following is used only for x-rays? - ANSWER -roentgen
The roentgen is only used for x-rays and gamma rays and does not include other
types of radiation.
Identify the correct conversion(s). - ANSWER -1 R = 2.58 × 10−4 C
1 Gy = 100 rads
1 Sv = 100 rem
1 rem = rad × QF
Identify the average dose of background radiation received by an individual in the
United States. - ANSWER -150-300 mrads (0.0015-0.003 Gy)
Identify the single largest contributor to artificial radiation exposure. - ANSWER
-medical radiation
Medical/dental radiation is the single largest contributor to artificial radiation,
accounting for more than half of all artificial radiation exposures.
The amount of radiation exposure an individual receives varies depending on
which of the following factors: - ANSWER -film speed
collimation
technique
exposure factors