Radiation Protection in Medical Radiography Flashcards

Terms Definitions
What are Eqd and EfD considered?
quantities
What was the location of the nuclear power plant that exploded in 1986 near Kiev in the Ukraine?
Chernobyl
What is damage to the body resulting from significant exposure to ionizing radiation called?
Organic
What is the method that compares the amount of radiation received with natural background radiations received over a given period?
BERT
What is the category of ionizing radiation that includes alpha and beta radiation?
Particulate
What is the dose called that ultimately may be delivered from a given intake of radionuclide?
Commitment
What is the radiation that produces positively and negatively charged particles when passing through matter?
Ionizing
What is the radiation exposure referred to that is delivered to the whole body over a period of less than a few hours?
Acute
What type of energy can humans safely control?
Radiant
What type of radiation is present in variable amounts in the earth's crust?
Terrestrial
What are white blood cells called that defend the body against foreign invaders?
Lymphocytes
What is radiation called of extraterrestrial origin?
Cosmic
What is the dose level called which individuals would have no chance of sustaining specific biological damage?
threshold
What is the processs that is the foundation of the interaction of xrays with human tissues?
Ionization
What is the degree to which the diagnostic study accurately reveals the presence or absence of disease in a patient?
Diagnostic efficacy
Define ionizing radiation.
Radiation that produces positively and negatively charged particles (ions) when passing through matter. Capable of transferring enough energy to the electrons to remove them from the atoms.
What is radiant energy?
Energy that is transferred by radiation, especially electromagnetic waves.
Define radiation.
The emission (to give or sendout) or propagation (to cause movement) of waves or particles.
What is an electromagnetic wave?
A wave that is propagating (causing movement) as a periodic disturbance of an electromagnetic field and having a frequency within the electromagnetic spectrum.
What is OPR?
Optimization for radiation protection
What does BERT stand for?
Background equivalent radiation time
What are the units of measurement (both traditional and international)?
International: Sieverts (Sv)
Traditional: 100 rem = 1 Sv
What is equivalent dose?
The quantity that attempts to take into account the variation in biologic harm that is produced by different types of radiation.
What is the measurement in the international system of units (SI) for equivalent dose?
Sieverts (Sv)
What is the measurement in traditional unit of measurement for the equivalent dose?
rem, 100 rem = 1 Sv
What is effective dose?
takes into account the dose for all types of ionizing radiation to organs or tissues being irradiated, and biologic components for developing a radiation induced cancer.
Define genetic radiation.
Radiation damage to future generations
What types of radiation are considered natural radiation?
Terrestrial, cosmic, internal
What types of radiation are cosmic?
Solar and galactic
What is the first decay product of radium?
Radon
What is the average dose per year from cosmic radiation?
.3 mSv (30 mrem) per year
What is the average annual dose from terrestrial and internal radiation?
.67 mSv (67 mrem) per year
What is the average annual dose from consumer products?
.11 mSv (11 mrem)
What is the average annual dose from air travel?
.005 - .01 mSv (.05 - 1 mrem/hour)
What is the average annual dose from nuclear fuel for power?
<1%
What is the average annual dose from atmospheric fallout?
.011 mSv (1.1 mrem)
What is the average annual dose from medical radiation?
.4 mSv (40 mrem)
What is the average total annual dose from manmade radiation?
.65 mSv (65 mrem)
When was the first nuclear weapons test in New Mexico?
July 16, 1945
When was the last nuclear weapons test in New Mexico?
September 23, 1992
When was the power plant accident on Three Mile Island?
March 28, 1979
When was the power plant accident in Chernobyl?
April 26, 1986
What does ESE stand for? How can it be indicated?
Entrance skin exposure; bone marrow dose, gonadal dose, fetal dose
Define BERT.
Method for comparing the amount of radiatioin received from a radiologic procedure with natural background radiation received over a given period.
What is EqD?
Equivalent dose; quantity that attempts to take into account the variation in biologic harm that is produced by different types of radiation.
What is a radionuclide?
An unstable nuclus that emits one or more forms of ionizing radiation to achieve greater stability.
What is organic damage?
Genetic or somatic changes in a living organism caused by excessive cellular damage form exposure to ionizing radiation.
What is diagnostic efficacy?
The degree to which the diagnostic study accurately reveals the presence or absence of disease in a patient.
What is EfD?
Effective dose; takes into account the dose for all types of ionizing radiation to organs or tissue and overall harm of those components for the development of radiation induced cancer (or risk of genetic damage)
What is an alpha particle?
consists of two protons and two neutrons
What is atomic number?
number of photons contained within the nucleus of an atom
Radon accounts for approximately what percentage of the gross common exposure to human beings from natural background radiation?
55%
Manmade radiation contributes what amount of mSv to the annual exposure?
.65 mSv
UV, visible light, infrared, microwaves, and radio waves are considered to be nonionizing because they:
Do not have sufficient kinetic energy to eject electrons from atoms
What is a naturally occuring process by which instability of the nucleus is relieved through various types of nuclear emissions.
Radioactive decay
Biologic damage is ________.
Damage in living tissue
Injury at the cellular level resulting from sufficient radiation at the molecular level is ________ damage.
Cellular damage
Genetic or somatic changes in a living organism is ________ damage.
Organic damage
Exit,or image formation, radiation comprises which types of photons?
Noninteracting and small-angle scattered photons
What type of photons contribute significantly to the exposure of the radiographer?
Compton-scattered photons
What is attenuation?
Absorption and scatter
During what x-ray interactions with matter is the energy of the incident photon partialliy absorbed?
Compton
When a high atomic number solution is either ingested or injected into human tissue or a structure to visualize it during an imaging procedure, what occurs?
Photoelectric interaction becomes enhanced, leading to an increase in the absorbed dose in the body tissues or structures that contain the contrast medium.
Which characteristics primarily differentiates the probability of occurrence of the various interactions of x-radiation with human tissue?
Energy of the incoming photon
What influences attenuation?
Effective atomic number of the absorber, mass density, thickness of the absorber
What type of interaction causes fog on a film?
Compton's
What is the most important mode of interaction between photons and the atoms of the patient's body for producing useful images?
Photoelectric absorption
What type of transmission occurs when some xray photons traverse an object without interacting?
Direct
What type of radiation is released as a result of a photoelectric interaction between an xray photon and an atom?
Characteristic
What is the unit of measure meaning thousands of volts?
kilovolts
What type of scatter radiation degrades the appearance of the finished radiograph by blurring the sharp patterns of dense objects?
small-angle
What is another name for coherent scattering?
Unmodified
What is the type of atomic number that is a composite Z number for many different chemical elements composing a material?
Effective
What is a common method devised to limit the effects of indirectly transmitted x-ray photons?
Air gap technique
What type of scatter occurs when a low energy photon interacts with one or more free electrons?
Thompson
What type of energy does an x-ray photon possess?
kinetic
What happens to patient dose when the kVp is increased?
Patient dose is decreased
What is the transference of electromagnetic energy to the atoms of a material?
absorption
What type of interaction occurs between an x-ray photon and an inner shell electron of an atom?
Photoelectric absorption
What refers to the number of of characteristic xrays emitted per inner shell vacancy?
Fluorescent yield
What interaction occurs between an x-ray photon and loosely bound outer shell electron of an atom?
Compton scattering
What is a composite Z for a material that consists of different chemical elements?
Effective atomic number (Zeff)
What is a positively charged electron called?
positron
What is it called when there is a reduction in the number of photons in the x-ray beam through absorption?
Attenuation
What is the byproduct of photoelectricf interaction?
Photoelectron
What is the interaction in which the energy of the incoming photon is transformed into two new particles, a negatron and a positron?
Pair production
What is the effective atomic number of soft tissue?
7.4
What is the effective atomic number of compact bone?
13.8
What type of contrast will result in dark areas on the film?
Negative contrast (air)
What characteristic primarily differentiates the probability of occurrence of the various tissue interactions of x-radiation with human tissue?
energy of the incoming photon
True or false. When kVp is decreased, the number of photoelectric interactions increases and the number of Compton interactions decreases; the patient absorbs more energy and patient dose is increased.
True
Pair production and photodisintegration are important in x-radiation interaction with matter in:
Therapeutic Radiology
The reduction in the number of primary photons in the x-ray beam through absorption and scatter as the beam passes through the object in its path defines:
Attenuation
True or false. Primary radiation emerges from the x-ray tube target and consists of x-ray photons of various energies.
True
True or false. The more electromagnetic energy received by the atoms of the patient’s body, the greater the possibility of biologic damage in the patient.
True
When a high energy number solution is either ingested or injected into human tissue or a structure to visualize it during an imaging procedure, what happens?
Photoelectric interaction becomes significantly enhanced, leading to an increase in the absorbed dose in the body tissues or structures that contain the contrast medium.
Most of the scattered radiation produced during radiologic procedures is:
compton scatter
What is the result of coherent scatter?
a simple change in the direction of the incident x-ray photon
Low-LET radiations such as x-radiation and gamma radiation are also:
sparsely ionizing
What is a quantity that attempts to summarize all aspects of different types of ionizing radiation that may lead to biologic harm?
Dose equivalent
What is biologic damage sustained by living organisms as a consequence of exposure to ionizing radiation?
Somatic damage
What is radiation exposure received by radiation workers in the course of working in their professional duties?
Occupational exposure
What is a quantity that attempts to take into account the variations in biologic harm that is produced by different types of ionizing radiation by considering the type and energy of the radiation?
Equivalent dose
What is radiation exposure of a population or group from low doses of different sources of ionizing radiation?
Collective Effective Dose
What radiation quantities accounts for some biologic tissues being more sensitive to radiation damage than other tissues?
Effective dose
The unit that measures exposure in air is the:
Roentgen
Which of the following terms describes the amount of energy per unit mass transferred from an x-ray beam to an object?
Absorbed dose
One rad is equal to how many grays?
.01
Which unit is used for personnel monitoring?
rem
The rate in which energy is deposited in matter describes:
LET (Linear Energy Transfer)
The most sensitive organ or tissue to radiation is:
The gonads
What was used as the first measure of of exposure for ionizing radiation?
Skin erythema
What is the unit of collective effective dose (ColEfD)?
Person-Sievert
The concept of tissue weighting factor is used for what purpose?
Account for the risk to the entire organism brought on by irradiation of individual tissues and organs
If the absorbed dose is stated in rads, gray may be determined by doing what calculation?
Dividing by 100
What quantity accounts for some biologic tissues being more sensitive to radiation damage than other tissues?
Effective dose
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