Radiation Protection Flashcards
radiation that produces positively and negatively charged particles when passing through matter
Ionizing radiation
T/F: X-rays can have varying degrees of penetration depending on their energy
True
the degree to which the diagnostic study accurately reveals the presence or absence of disease in the patient
Diagnostic efficacy
ORP
Optimization for radiation protection
Cardinal rules for radiation protection
Time, distance, shielding
Cosmic radiation occurs in which two forms?
Solar and Galactic
Long-lived radioactive elements such as uranium-238, radium-226, and thorium-232 that are present in variable quantities in the crust of the Earth
Terrestrial radiation
What is the most common unit of measure of equivalent dose?
Millisievert
What is a method of explaining radiation to the public?
BERT (Background equivalent radiation time)
T/F: radiation-induced cancer does have a dose level at which individuals would have a chance of developing this disease.
False
Compton scattering is synonymous with:
incoherent scattering.
If two anatomic structures have the same density and atomic number but one is twice as thick as the other, the thicker structure will absorb
twice as many x-ray photons.
In photoelectric absorption to dislodge an inner-shell electron from its atomic orbit, the incoming x-ray photon must be able to transfer a quantity of energy
as large as or larger than the amount of energy that holds the electron in its orbit.
The probability of occurrence of photoelectric absorption _________ as the energy of the incident photon decreases and the atomic number of the irradiated atoms _________.
increases markedly; increases
What are by-products of photoelectric absorption?
Photoelectron and characteristic photon
Which of the following particles is considered to be a form of antimatter?
Positrons
Which of the following results in all-directional scatter?
Compton interaction
The x-ray photon energy required to initiate pair production is
1.022 MeV
Which of the following is not a type of interaction between x-radiation and biologic matter?
a. Compton scattering
b. Bremsstrahlung
c. Photoelectric absorption
d. Pair production
B
Exposure is measured in:
coulombs/kg (SI) or milliroentgens
absorbed dose is measured in:
milligray
effective dose is measured in:
millisievert
Effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unnecessary exposure to ionizing radiation defines:
Radiation protection
The amount of ionization produced in the air when ionizing radiation is present is known as:
Exposure
The millisievert (mSv) is equal to:
1/1000 of a sievert
intended to be the best estimate of overall harm that might be produced by a given absorbed dose of radiation in human tissue.
Effective dose
average amount of natural background radiation
3.1 mSv
Which of the following processes is the foundation for imaging of the interaction of x-rays with human tissue?
Ionization
An equivalent dose as low as 250 mSv delivered to the whole body may cause which of the following within a few days?
A. An increase in the number of lymphocytes in the circulating blood.
B. A substantial decrease within a few days in the number of lymphocytes or white blood cells that are the body’s primary defense against disease.
C. A drop immediately to zero in the lymphocyte count.
D. A large increase in the number of platelets.
B
How is actual radiation dose to the global population from atmospheric fallout from nuclear weapons testing received?
A. It is received all at once within a short period of time after such a test.
B. It is received in large quantities within a period of 2 years after such a test.
C. It is not received all at once but instead is delivered over a period of years at changing dose rates.
D. No fallout from such testing is ever received.
C
Which of the following is recognized as the main adverse health effect from the 1986 Chernobyl nuclear power accident?
A. Increase in the incidence of leukemia in adults
B. Increase in the incidence of leukemia in children
C. Increase in the incidence of thyroid cancer in adults
D. Increase in the incidence of thyroid cancer in children and adolescents
D
If an interaction occurs, electromagnetic energy is transferred from the x-rays to the atoms of the patient’s biologic tissue. This process is called:
Absorption
The amount of energy absorbed per unit mass
Absorbed dose
______ are the photons that have undergone either absorption or scatter and do not strike the image receptor
Attenuated photons
The [more/less] a given structure attenuates radiation, the brighter its appearance will be on a raw digital detector image
less
Exit, or image-formation, radiation is composed of which of the following?
A. Primary photons and wide-angle Compton scattered photons
B. Noninteracting and small angle scattered photons
C. Very low energy photons D. Auger electrons
B
Which of the following contributes significantly to the exposure of the radiographer?
A. Positrons
B. Electrons
C. Compton scattered photons
D. Compton scattered electrons
C
In the radiographic kilovoltage range, which of the following structures undergoes the most photoelectric absorption?
Compact bone
In which of the following x-ray interactions with matter is the energy of the incident photon partially absorbed?
Compton
In which of the following x-ray interactions with matter is the energy of the incident photon completely absorbed?
Photoelectric
Which of the following characteristics primarily differentiates the probability of occurrence of the various interactions of x-radiation with human tissue?
A. Energy of the incoming photon
B. Direction of the incident photon
C. X-ray beam intensity
D. Exposure time
A
Which of the following influences attenuation?
1. Effective atomic number of the absorber
2. Mass density
3. Thickness of the absorber
1, 2 and 3
A decrease in contrast of the image by adding an unwanted additional exposure (radiographic fog) results from:
Compton Scattering
The interactions of x-ray photons with any atoms of biologic matter are:
A. Able to be preplanned to selective atoms to limit radiation exposure to those atoms
B. Important only in therapeutic radiology
C. Random, so the effects of such interactions cannot be predicted with certainty
D. Unimportant in diagnostic radiology, thus making radiation protection unnecessary
C
Although coherent scattering is most likely to occur ____________, some of this unmodified scattering occurs throughout the diagnostic range and can result in small amounts of radiographic fog.
at less than 10 keV
The ALARA principle provides a method for comparing the amount of radiation used in various health care facilities in a particular area for specific imaging procedures. This information may be helpful to many
Regulatory agencies
Which of the following instruments is called a cutie pie?
Ionization chamber-type survey meter
Why is a question concerning the amount of radiation a patient will receive during a specific x-ray procedure difficult to answer?
1. Because the received dose is specified in a number of different units of measure.
2. Because the scientific units for radiation dose are normally not comprehensible by a patient.
3. Because the patient should not receive any information about radiation dose.
1 and 2
During the process of coherent scattering, an incident low-energy x-ray photon interacts with:
an atom and may transfer its energy by causing some or all of the electrons of the atom to momentarily vibrate and radiate energy in the form of electromagnetic waves.
If two anatomic structures have the same density and atomic number but one is twice as thick as the other, the thicker structure will absorb
twice as many x-ray photons.
