Radiography: Radiation Physics and Radiobiology Flashcards
Which of the following produces the most dangerous form of scatter radiation: the Compton effect, Grenz rays, coherent scattering, or the photoelectric effect?
The Compton effect
According to what principle can RTs reduce their radiation dose by one-fourth when they double their distance from the radiation source?
The inverse square law
What is the main reason an X-ray beam signal loses strength as it travels away from the X-ray tube?
Divergence of the X-ray beam
The wavelength of an X-ray photon is measured as the distance between _________________ .
crests
An extension of what equation describes the relationship between photon energy and photon wavelength as being inversely proportional?
Planck’s constant/equation
What is the most common interaction that occurs between X-rays and contrast media that’s used for certain radiographic procedures?
The photoelectric effect
Which of the following cells in the body are NOT considered to be highly radiosensitive: basal cells, erythroblasts, lymphocytes, or nerve cells?
Nerve cells
The reddening of skin due to irradiation is known as ____________________ .
erythema
X-rays and gamma rays are often also called ______________.
photons
Structures that absorb X-rays and appear bright or white on radiographs are classified as being _______________.
radiopaque
Generally speaking, the probability of Compton scattering occurring _______________ as X-ray energy _________________ .
decreases; increases
Genetic cell damage, malignant disease, and cell death are the main effects of _____________ .
cell irradiation
The measurement of biological damage to living tissue as a result of radiation exposure is called the ________________ .
dose equivalent
Radiation dose levels as low as ______________ have caused observable effects.
0.10 Gys
The ____________________ of radiation occurs when DNA is damaged.
direct effect
What X-ray photon-to-tissue interaction primarily involves K-shell electrons?
Photoelectric absorption/effect
What is also known as classical or Thompson scattering?
Coherent scattering
What results when the effects of radiation become more severe as radiation dose increases?
Deterministic effects
The effects of radiation where the long-term probability of occurrence, not the severity of occurrence, are proportional to the radiation dose are known as ________________ .
stochastic effects
The majority of a projectile electron’s kinetic energy is converted into ______________ .
heat
___________________ are the result of projectile electrons that are slowed down by positively charged nuclei and change direction.
Bremsstrahlung X-rays
________________ is kinetic energy that’s released in a unit mass of air (also considered radiation exposure).
Air kerma
The _________________ is the amount of energy per unit mass absorbed by an object that has been irradiated.
absorbed dose
The total reduction in the number of X-rays remaining in an X-ray beam after it penetrates tissue is called _____________________________ .
attenuation
The difference between the ways and amounts that parts of the body interact with and absorb radiation is called ____________________ .
differential absorption
Cancer and genetic defects are examples of what type of effects?
Stochastic effects
The initiation of cancer growth or development is called _________________ .
carcinogenesis
What percentage of the total energy applied to an X-ray tube target is converted into X-rays?
About 1%
__________________________ is the emission of electrons after being stimulated by heat, commonly by the X-ray tube filament.
Thermionic emission
The X-ray beam is most intense at which part of the X-ray tube?
The cathode end
What is the measurement of the average annual gonadal radiation dose of individuals who are of childbearing age?
The genetically significant dose
What is the formula for calculating the cumulative effective dose?
Multiplying the person’s age by 10 mSv
_____________________is the amount of energy deposited by radiation per unit length of tissue.
Linear energy transfer
What does the following equation calculate?
Radiation weighting factor (WR) × Tissue weighting factor (WT) × Absorbed dose (D)
The effective dose
Radiation that’s emitted from the X-ray tube and directed towards the patient for imaging purposes is called __________________ .
the primary beam
Radiation that spreads in many directions after interacting with a substance or tissue is called ____________________
scatter radiation
A graphical depiction of the relationship between the radiation received and a patient’s response to it is called _________________.
a dose-response curve
_________________ is the measurement of the damage done by a given type of radiation per unit of energy deposited in biological tissues.
Relative biological effectiveness (RBE)
