V1 - Safety Flashcards
A Bremsstrahlung interaction is best described by which statement?
An electron is slowed and changes direction
When the frequency of the voltage waveform supplied to the x-ray tube is increased, what aspect is reduced? (3 answers)
- Patient exposure.
- Heat loading on the anode disk.
- Average wavelength of the x-ray beam.
Which feature of the fluoroscopic equipment is designed to reduce entrance skin exposure to the patient?
Beam Filtration
What is the dose-response relationship of radiation-induced skin cancer?
Threshold
Which term refers to the radiation that exits the x-ray tube through the collimator?
Primary
A portable knee exam performed in the operating room results in beam intensity of 2.5 mgy at 32 inches. What is the intensity of the beam if the same exposure factors are used for a post-op knee at a distance of 40 inches?
1.60 mgy
For which long term effect is a 28-year-old radiographer with a cumulative effective dose (CumEfD) of 200 mSv (20 rem) at an increased risk?
Cancer
What is the term for a reduction in x-ray photon intensity as it passes through the patient?
Attenuation
If a radiographer recieves an exposure of 0.05 msv at a distance of 1.5 feet from the tube of a portable x-ray unit, what will the exposure be at a distance of 6 feet from the tube?
0.003 msv
What is the impact of using 2.5 mm of al/eq filtration on the primary x-ray beam?
Reduction of the patient’s skin dose
The Z number of oxygen is 8. The elemental oxygen atom has two electron shells. How many electrons occupy an electrically neutral oxygen atom’s outer shell?
6
Which protective feature is designed to reduce exposure to the patient during fluoroscopic procedures?
Foot switch
As a result of imaging pregnant patient’s, which is the fetal exposure for most radiographic exams?
Less than 0.01 gray (1 rad)
Which accurately describes the radiation dose absorbed by bone marrow?
The dose will be less than the entrance skin exposure
In an x-ray tube, what is the source of electrons used to make x-rays?
Filament
Which process describes the electron-target interaction in which most diagnostic x-rays are produced?
The filament electron misses all of the orbital electrons and interacts with the target atom nucleus
Which input intensifier screen provides the best radiation protection to the patient during fluoroscopy?
25 cm
The annual effective dose equivalent limit for infrequent exposures recommended by the National Council on Radiation Protection (NCRP) for a member of the general public is equal to how many msv?
5
What causes the build-up of heat at the anode?
Electrons colliding with the target
How much can exposure to the lens of the eyes be reduced by utilizing the PA projection of the cranium over the AP projection?
95%
The majority of x-rays in the useful beam are created as a result of which process?
Fast-moving electrons approach the nucleus of the target atom and slow down.
Which is the genetically significant dose (GSD) for the population of the United States?
0.20 mSv
How can digital radiography contribute to patient dose reduction today, in spite of generally being slower in system speed than 400 speed film screen systems?
Higher kVp should be used in digital
Which factor will decrease the patient’s dose during fluoroscopy?
Bring the image intensifier as close as possible to the patient
Which term describes stray radiation that is emitted through the x-ray tube housing?
Leakage
In a typical x-ray examination room, what is considered a secondary protective barrier?
Ceiling
Which change causes a decrease in resistance and an increase in current flow?
Increasing the diameter of the conductor
What characteristics do high linear energy transfer (LET) radiations have when compared with low-LET radiation?
Increased mass, decreased penetration
Which statement correctly describes the LD 50/30?
Lethal dose for 50% of the population in 30 days
Which aspect of electrical power is responsible for accelerating electrons in an x-ray tube?
Potential difference
How can a radiographer reduce a patient’s exposure during a lumbar spine series?
Carefully explain the procedure
Which radiation dose is required to produce mitotic death?
Less than the dose needed to produce apoptosis in slowly dividing cells or nondividing cells
The bucky slot cover should offer at least what lead thickness?
0.25 mm
Which grid ratio results in the lowest dose to a patient, because less mAs is required?
5:1
Where is the safest place for the radiographer to stand during fluoroscopy?
90 degrees and one meter from the patient
Which statements are accurate about control monitoring badges? (2 answers)
- Should be kept in a distant room from the radiation area.
- Measures background exposure during transportation, handling, and storage.
Which item can be used as an indicator of the quality of the diagnostic x-ray beam?
kVp
Which items can be used as indicators of the quality of the diagnostic x-ray beam? (2 answers)
- HVL
- kVp
What is the dose area product (DAP) if the collimated fields is 10 x 10 cm with a dose of 2 mgy/minute?
200 mgy per cm squared
For the protection of the radiographer, how long must the exposure cord be on a mobile radiographic unit?
2 meters
Which type of personnel dose monitoring devices is the best choice to monitor the whole body dosage of radiographer?
OSL dosimeter
What is the minimum thickness of lead required for protective lead curtains?
0.25 mm lead equivalence
What is the maximum speed of filament electrons as they travel toward the anode?
Half the speed of light
What type of relationship does cell growth rate have on the sensitivity of tissues ionizing radiation?
Direct
Which term best describes the process by which most x-ray-induced cellular damage occurs?
Indirect theory
Which is an advantage of using a OSL dosimeter opposed to a film badge?
Not fogged by heat
When dealing with radiation exposure, what is the most effective protection for the radiographer?
Distance
The highest potential dose to the radiographer during c-arm fluoroscopy originates from which source?
The side where x-rays enter the patient
Which condition must be met before dianostically useful characteristic x-rays can be produced?
An inner shell electron must be completely removed
Which factor determines the amount of energy of a brems x-ray?
The distance between the filament electron and the nucleus of the target atom
Which may be effects of fetal irradiation? (4 answers)
- Growth retardation.
- Prenatal death.
- Childhood and early adult cancers.
- Spontaneous abortion.
Which is the most appropriate reason for the application of gonadal shielding?
To safe guard the reproductive potential of patients
What is the most likely consequence for a cell when an x-ray photon interacts with and inactivates the cell’s master molecule?
Cell Death
