Safety Flashcards
ALARA is an acronym for:
As Low as Reasonable Achievable
Cells that are oxygenated are more susceptible to radiation damage. This describes:
Oxygen enhancement ratio
When we increase the number of photons in the x-ray beam (mAs increase) we:
Increase intensity, quantity of beam and increase potential biological damage
Radiation that is contained in the environment is called:
Natural background
Cataractogenesis, life span shortening, embryologic effects, and carcinogenesis are examples of…
Long-term somatic effects
Radiation with a high LET:
Is highly ionizing
The effective dose limit for radiographers is:
50 mSv per year
The radiation dose that would bring genetic injury to the total population is called:
Genetically significant dose
Use of a thyroid shield of at least what thickness should be used for fluoroscopy?
0.5 mm Pb equivalent
How thick are primary protective barriers?
7 ft high, 1.5 mm (1/16 in) Pb equivalent
The Bucky slot cover must be at least:
0.25 mm Pb equivalent
Thermoluminescent dosimeters use what type of crystals to record dose?
Lithium fluoride
What is the embryo-fetus equivalent dose limit per month?
0.5 mSv
Optically stimulated luminescence (OSL) dosimeters are sensitive to exposure as low as:
0.01 mSv
The energy stored in an OSL dosimeter is released when the dosimeter is exposed to:
Laser
The personal dosimeter report reads in what unit of measurement?
Rem or mrem
The SI unit of absorbed dose is the:
Gray
Use of a thyroid shield of at least what thickness should be used in fluoroscopy?
0.50 mm
for purposes of radiation protection the xray beam is filtered, xray tubes operating above 70 kvp must have a total filtration of:
At least 2.5-mm aluminum equivalent
Leakage radiation from a diagnostic x-ray tube may not exceed:
1 mGy per hour, measured at 1 meter from the housing
Which of the following functions to protect the x-ray tube and patient from overexposure in event of AEC malfunction?
Backup timer
The Roentgen, as a unit of measurement, expresses:
Exposure in air
The control dosimeter that comes from the monitoring company should be:
Stored in a radiation free area
The annual occupational dose limit is?
50 mSv
The collimator light and actual irradiated area must be accurate to within what percentage of the SID?
2%
Biological effects resulting from diagnostic exposures to radiation appears to follow a _________ relationship.
Linear, nonthreshold
The majority of damage to body cells from radiation exposure results from the:
Indirect effect
Skin response to radiation, resulting in hair loss is termed:
Epilation
Radiographers use monitoring devices to record their monthly exposure to radiation. The devices suited for this purpose include the:
1) pocket dosimeter
2) TLD
3) OSL
2,3
The number of repeated images can be reduced by employing:
effective communication skills, proper immobilization, and proper exposure factors
A dose of radiation exists below which the response will not occur but when a certain dose is achieved the response will be proportional to the dose. This is an example of:
Linear, Threshold
The most sensitive macromolecule found in human cells is;
DNA
One of the components of the Law of Bergonie and Tribondeau states:
radiosensitivity is inversely proportional to the degree of differentiation
Which of the following units is used for personnel exposure:
Sievert
What is the minimum required amount of lead equivalent that a lead apron must have?
0.25 mm
Which of the following units describes patient exposure?
Rad
Luxel Dosimeter (OSL) are sensitive enough to read exposures as low as:
0.01 mSv
Secondary barriers are constructed to protect people from:
scatter radiation
The mA used in fluoroscopy must not exceed
5 mA
Which of the following defines the gonadal dose that, if received by every member of the population, would be expected to produce the same total genetic effects on that population as the actual dose received by each of the individuals?
genetically significant dose
Skin response to radiation, resulting in reddening, known as:
Erythema
What is the material used to express shielding equivalents?
Lead
LET and biological damage are:
Directly proportional
The effective dose equivalent limit for a wait room requires that family members (infrequent exposures) receive no more than ________ per year
5 mSv
When it does not interfere with obtaining diagnostic information, gonadal shielding should be considered for which type of patients?
all patients, especially children and adults of reproductive age
The lead window by the control booth must have what lead equivalent?
1.5 mm
The number of repeat radiographs can be reduced by employing all of the following except;
High ratio grids
Proper immobilization
Careful selection of exposure factors
Effective communication skill
High ratio grids
Fetal dose limit during gestation is equal to:
5 mSv
Which of the following units describes exposure in air of x or gamma rays?
Coulombs per kilogram
The exposure at table top used in routine fluoroscopy must not exceed:
100 mGy per minute
Which of the following personnel monitoring devices cannot detect radiation levels below 10 mrem?
Film Badge
Primary barriers are constructed to protect individuals from:
The useful beam
Which of the following exposure factors will deliver the most amount of radiation exposure to the patient?
50 mAs, 90 kVp
25 mAs, 100 kVp
200 mAs, 70 kVp
100 mAs, 80 kVp
200 mAs, 70 Kvp
The source to skin distance for mobile x ray units is:
30 cm
An OSL dosimeter is made using:
Aluminum oxide
___ is the unite that defines occupational exposure?
Sievert
In mobile radiography, the exposure switch should be on a cord that is at least _______ ft long
6
The required lead equivalent for lead gloves is:
0.25 mm
The fluoroscopic timer is set to ________ increments before resetting.
5 min
Following the irradiation of approximately 500 rad to the testes:
Permanent sterility occurs
The period of time after an acute exposure to radiation in which the initial effects of the exposure are seen is called the:
Prodromal stage
The use of which of the following devices helps to reduce patient dose?
1) gonadal shielding
2) Collimator
3) grids
1,2
Lead aprons are worn during fluoroscopy to protect the radiographer from exposure to radiation from the patient which occurs due to:
Compton scatter
What is the most effective type of shield for an anterior and lateral male gonadal protection during radiography procedures?
Shaped contact (contour)
According to the NRCP guidelines, the annual occupational whole body dose equivalent limit is?
50 mSv
The single most important scattering object in both fluoroscopy and radiography is?
Patient
A student radiographer who is under the age of 18 must not receive an annual occupational dose greater than:
1 mSv
Cataractogenesis does not occur at low levels of radiation exposure. Therefore it is best expressed by which of the following dose-response relationships terms?
Threshold
Occupational radiation monitoring is required when it is possible that the individual might receive more than:
1/10th of the annual dose limit
Which personnel monitoring device uses lithium fluoride to measure radiation?
TLD
The dose-response curve that appears to be valid for genetic and some somatic effects is/are the:
1) Linear
2) nonlinear
3) nonthreshold
1,3
How tall must the wall of the primary radiation barrier be at a minimum?
7 ft
Which of the following personnel radiation monitors will provide an immediate reading?
Pocket dosimeter
The target theory applies to
DNA molecules
Which type of interaction is shown in the picture below?
Bremsstrahlung interaction
Which of the following must happen for x-ray production to occur?
Acceleration, Focusing and Deceleration of electrons
True or False: Under 70 kVp, 100% of the x-ray beam is formed by characteristic interactions.
False
Wavelength and frequency are ___________.
Inversely proportional
The cumulative occupational exposure for a 22-year-old is:
220 mSv
Quality of the x-ray beam mainly deals with:
Penetration power of the beam
Attenuation is the reduction of the primary x-ray beam that reaches the receptor through _______
Absorption and scatter
X-rays travel at:
Speed of light
X-rays have the characteristics of both:
waves and particles
Which interaction with matter results in the most scatter radiation?
Compton interactions
Which of the following has the highest frequency?
Shorter wave length
Approximately ______% of interactions above 70 kVp are characteristic interactions.
15 %
Electrons are formed on the cathode side of the x-ray tube by what process?
Thermonic emission
The Cathode is the negatively charge part of the tube: (T/F)
True
When electrons slam into the anode target, _______ is the majority of what is produced.
Heat
The secondary protective barrier used in room shielding must be at least how thick?
1/32 inch Pb equivalent
Which of the following are interactions that occur with patients?
Coherent and compton
Which interaction with matter is shown below?
Coherent scatter (excites atom)
Which interaction with matter causes the most biological damage to tissue?
Photoelectric absorption
Increase of photoelectric absorption occurs when:
low kVp is used
In regards to x-ray interaction, when the atomic number of a structure is higher:
more likelihood x-rays are absorbed
The inverse square law states that “the intensity of radiation from a source varies ______ as the square of distance”
Inversely
If you were to measure the intensity of radiation to be 20 R at 2 meters - what would the intensity be if you were to double the distance to 4 meters?
5 R
Inverse square law:
I(1) / I (2) = D(2) squared / D(1) squared
The ______ beam is the beam that creates our images.
Remnant
An increase in filtration will increase quality of the x-ray beam. (T/F)
True
The x-ray beam is ______.
Heterogenous
