Safety Flashcards
The frequency of a sine wave is measured by the
Number of times per second that the crest passes a given point
All electromagnetic energy moves through space at the same
Velocity
Which quality factor is a key visibility of detail?
Contrast
The contrast in the radiographic image is controlled by
KVp
The unit of potential difference is the
Volt
How does scatter radiation fog reduce the visibility of detail in a radiographic image?
Decreases contrast
The NCRP recommended monthly equivalent dose limit for a pregnant worker is ___ mSv
0.5
What is the SI unit of expsoure that measures radiation in the air?
Air karma (Gy-a)
The unit commonly used to report the effective dose to occupational workers in the US is
Msv
Which of the following changes decrease the dose to the limited operator?
Minimizing time spent in the radiation area, increasing the distance between the operator and the source of radiation, use shielding control booth and lead apparel
When an image demonstrates many densities, and there is little difference between the densities, the image is described as having
Long scale contrast
What is required to move the electron stream rapidly across the x-ray tube?
High potential difference
What type of radiation is produced when an incoming electron interacts with the K-shell electron in the tungsten atom?
Characteristic radiation
The primary controlling factor is of penetration of X-rays
Kvp
The degree of angulation of the x-ray tube target will determine the
Effective focal spot
Which of the following are characteristics of x-rays
Travel in straight lines, can cause biological effect on tissue, cannot be felt seen or heard
When an image demonstrates great differences between the densities, the image is described as
High contrast
What term is applied to the distance from one crest to the next in a sine wave
Wavelength
Patient doses in radiography are usually calculated as the
Entrance skin exposure (ESE)
If the mA doubles, the quantity of the exposure will
Double
What are the four primary factors that directly affect how the x-ray image looks?
Density, contrast, distortion, and spatial resolution
Compton scatter occurs when an x-ray photon interacts with which part of the atom in the patients body
Outer orbital electron
During the photoelectric effect, an incoming photon interacts with the atom in the patients body. What happens to the photon with this effect?
It is totally absorbed by the atom
What is the guiding philosophy of radiation protection?
ALARA
Which of the following are the prime factors of exposure in radiography?
MA, time, kvp, SID
Contrast is directly influenced by
Fog & collimation
Which of the following is an accurate statement regarding the characteristics of x-rays? They can
Penetrate matter
The SI unit for measuring the absorbed dose is the
Gray (Gy-t)
Higher kvp settings produce images with
Long scale conrast
As kvp is increased, Compton interactions will
Increase
A smaller effective focal spot produces
Greater image sharpness
The precise area on the target where the x-rays strike is called the
Focal spot
Which of the following occurs when the mA is doubled
Radiographic density increases and there are twice as many photons in the X-ray beam
Which of the following reduces the amount of scatter radiation fog on an image?
Decrease in kvp, decrease in field size
The federal regulation for the lead equivalency of protective aprons that are worn in the radiographic room is ___ mm
0.5
Which of the following transformers would have more windings on the primary side?
Step down transformer
Which of the following will minimize shape distortion?
Position plane of subject parallel to plane of IR and position the CR perpendicular to IR and subject
The lead equivalent thickness of a gonad shield should be ___ mm
0.5
The primary controlling factor of contrast is
Kilovoltage
Scatter radiation fog will 1) Increase density,2) decrease contrast, 3)reduce visibility of detail
Increase density, decrease contrast, reduce visibility of detail
A change from the small focal spot to the large focal spot results in
Decreased resolution
When a body part appears on a radiograph as longer than it actually is, the term used is
Elongation
The factors that affect X-ray quality are
Kilovoltage and filtration
Short term affects of radiation would occur within how long
3 months
The photoelectric effect occurs when an incoming photon from the primary beam interacts with which part of the atom in the patients body?
Inner shell electron
The annual effective dose limit for an occupational radiation worker is
50 mSv
Which of the following can the limited operator do to keep radiation exposure to patients as low as reasonably achievable
Use a small radiation field, use the highest kvp possible, and never use an SID below 40 inches
The geometric factors that affect the formation of the image are
SID and OID
What are the four essential elements required for x-ray production?
A target, a vacuum, an electron source, and high potential difference
