Final Flashcards
Fluoroscopic machines must create an audible alarm signal after this much fluoro time:
5 minutes
Protective barriers must be shielded up to a height of at least:
7 feet
Secondary protective must provide as much shielding as:
1/32nd inch Pb/Eq
The amount of radiation escaping the tube housing as “leakage” must not exceed:
100 mR/hour at 1 meter
The atomic number of lead is:
82
Primary protective barriers must provide as much shielding as:
1/16th inch Pb/Eq
Source to tabletop distance for fixed fluoroscopic units must not be less than:
15 inches
The whole body, cumulative, lifetime exposure of a 29 year old technologist may not exceed:
29 Rem
Source to tabletop distance for mobile fluoroscopic units must not be less than:
12 inches
Briefly describe what is meant by the term ALARA.
As Low As Reasonably Achievable - balance of image quality and patient dose
Briefly describe what is meant by the term remnant radiation.
The portion of the primary beam that survives trip through the patient and emerges towardsthe image receptor to form the “shadow” image
Briefly describe what is meant by the term deadman switch.
Continuous pressure required - used in fluoroscopy
Briefly describe what is meant by the term primary barrier.
Struck by primary x-ray beam - requires at least 1/16th of an inch lead equivalency
List the 3 Cardinal Rules of radiation protection.
Time, Distance, Shielding
A tech at 8 feet from the patient receives 2 mR of exposure from scatter. At 2 feet the tech would receive:
32 mR
A tech at 3 feet from the patient receives 16 mR of exposure from scatter. At 6 feet the tech would receive:
4 mR
The most radiosensitive of all body systems is:
Hematopoietic
The discovery of x-ray in November of 1895 is credited to:
Roentgen
Voluntary motion is best controlled by:
Clear communication
Involuntary motion is best controlled by:
Short exposure time
Red blood cells are also known as:
Erythrocytes
Watch dial painters from the 1920’s and 1930’s were exposed to the radioactive material:
Radium
The city of Chernobyl within the Ukraine is known for:
Nuclear power plant meltdown
Ionizing radiation that comes from the Earth itself is known as:
Terrestrial
The greatest amount of Natural/Background exposure to humans is due to:
Radon gas
The radioactive debris from nuclear detonations is known as:
Fallout
The formula that allows a tech to maintain image density while changing both KVP and MAS is the:
15/50 Rule
The radiographer’s greatest tool in minimizing the production of scatter is the:
Collimator
Platelet cells of the blood are also known as:
Thrombocytes
Primary x-ray that has been redirected due to interaction with matter is known as:
Scatter radiation
Briefly describe what is meant by the term epithelial crypt cells.
Specialized cells that replace worn out epithelial linings
Briefly describe what is meant by the term involuntary motion as it pertains to x-ray.
Motion that cannot be controlled by the patient - heart beat, peristalsis, pulsation of vessls
Briefly describe what is meant by the term attenuation as it pertains to x-ray.
The partial absorption and partial transmission of x-ray energy as it passes through matter
Briefly describe what is meant by the term divergent as it pertains to x-ray.
The x-ray beam spreads out as it passes through space, follows Inverse Square Law
Briefly describe what is meant by the term polyenergetic as it pertains to x-ray.
The primary beam exists at a variety of x-ray energies
Briefly describe what is meant by the term ESE - Entrance Skin Exposure.
Area where x-ray beam enters the patient’s body - site of greatest exposure to patient
Briefly describe the benefits of using a low ratio grid versus a high ratio grid for a portable exam.
Lower MAS/patient dose
Greater latitude in grid alignment and usage
Briefly describe why skull x-rays are routinely taken with a PA versus an AP projection.
ESE - minimize dose to the radiosensitive eyes and thyroid gland
The annual dose limit for whole body occupational exposure is:
5 Rem
The minimum lead equivalency for protective aprons used in fluoroscopy is:
0.5 mm
The amount of time that an area is occupied by people is known as:
Occupancy factor
The percentage of time that an x-ray tube is energized and producing radiation is known as:
Use factor
The minimum lead equivalency for a thyroid shield is:
0.5 mm
The annual dose limit for a student less than 18 years of age is:
0.1 Rem
The annual dose limit for occupational exposure to the skin and extremities may not exceed:
50 Rem
Fluoroscopic x-ray intensity at tabletop must not exceed:
10 R/minute
The level of radiation activity within a room is known as:
Workload
Fetal dose limit for any single month of gestation is:
0.05 Rem
The annual dose limit for whole body exposure of the general public is:
0.5 Rem
The annual dose limit for occupational exposure to the lens of the eye may not exceed:
15 Rem
The x-ray tube housing must be shielded to at least:
1/16th inch Pb/Eq
Fetal dose limit for an entire 9 month gestation is:
0.5 Rem
To reduce patient dose the primary x-ray beam must be filtered to at least:
2.5 mm Al/Eq
As KVP increases patient absorbed dose:
Decreases
As imaging system speed increases patient dose:
Increases
The speed of digital imaging systems is largely controlled by:
Sampling size/rate
As grid ratio increases patient dose:
Increases
The most radiosensitive of all body cells are
Lymphocytes
As the volume of tissue irradiated increases scatter production:
Increases
Epithelial tissues are found within the
Intestinal linings, respiratory tract, and lining of blood cells
The layer of the alimentary canal that possesses glands, blood vessels, and nerves is known as the
Submucosa
According to the law of Bergonie and Tribondeau
Mature cells are insensitive, highly reproductive cells and long mitotic phases are sensitive
Radiation safety measures for techs are based upon this curve
The linear nonthreshold
As the oxygen level within a cell increases it’s radio sensitivity
Increases
The ionizing radiation particle comprised of 2 protons and 2 neutrons is
Alpha
Rad x QF is the formula for calculating
Rems
The international unit for radiant energy absorbed in tissue is
Gray
The traditional unit for radiant energy absorbed in a medium is
Rad
The international unit for calculating X-ray in air is
Air Kerma
The traditional unit for calculating X-ray in air is
Roentgen
The threshold dose of whole body radiation considered to be lethal is
300 rads
The international unit for the radioactive decay is
Becquerel
The international unit for calculating exposure equivalent is
Sievert
Permanent sterility in males is
500-600 Rads
The traditional unit for the rate of radioactive decay is
Curie
Research assistant to Thomas Edison
Clarance Dailey
The traditional unit for calculating exposure equivalent
REM
Structures responsible for protein synthesis
Ribosomes
Somatic cells divide by
Mitosis
In Cell division each parent cells possess
46 chromosomes
Network of vesicles and tubules within a cell is known as
Endoplasmic Reticulum
The nuclear membrane dissolves and centrioles begin to migrate in opposite directions during
Prophase
(T/F) All cells within the human body contain a equal # of mitochondria
False
A method of displaying specific cell sensitivity to a specific type of radiation
Survival curve
Platelet cells of the blood are also known as
Thrombocytes
The stochastic effect known as “all or nothing” is
Stochastic effect
A person developing leukemia 15 years after an exposure to ionizing radiation
Stochastic
As the oxygen level within a cell increases it’s radiosensitivity
Increases
The layer of the alimentary canal that possesses glands, blood vessels, and nerves is the
Submucosa
Microwaves
Are not capable of ionizing matter
The amount of energy deposited in tissue per unit of distance is known as
LET
Frequency is measured in
Hertz
The interraction most responsible for the absorption of X-ray energy by matter is
Photoelectric
As the wavelength of a given type of EMR decreases it’s energy
Increases
Gamma
Is not a matter based ionizing radiation
The interraction between photons and inner shell electrons is
Photoelectric
Oxygen rich tissue suffers damage compared to oxygen poor at a rate of
2-3x greater
5 rads of a test radiation will cause the same biologic reaction as 40 rads of our reference radiation. The RBE of our test is
8 (40/5)
Cell death during interphase is known as
Apoptosis
Exposure to a cell just before cell division will most likely result in
Mitotic delay
Biological damage sustained by a living organism due to ionizing radiation is best defined by
Somatic effects
The most radio sensitive of all body systems is the
Hematopoietic system
XRAY leads to
Free radical formation
X-ray has a high
OER
Alpha has a low
OER
