CORE- Image Production Flashcards
Which technical factor is used to alter radiographic contrast?
kVp
An x-ray exposure is made using the following factors: 400 mA, 0.02 seconds, 80 kVp, 40 in SID, and the large focal spot. What is the mAs for this exposure technique?
8 mAs (400x0.02)
Each square picture element in a digital viewing monitor is called a
pixel
When an image demonstrates only a few densities, and there is a great difference between the densities, the image is described as having
short-scale contrast
If the automatic exposure system fails during an exposure, which built-in control will terminate the exposure?
back-up timer
Which of the following, if increased, will result in increased radiographic density? 1. increased mA, 2. increased exposure time, 3. increased kVp
1,2, and 3
Which quality factor is a key to visibility of detail?
contrast
The primary controlling factor of penetration of x-ray is
kVp
Which of the following tells the operator that the correct exposure has been received by the phosphors in the imaging plate?
exposure indicator number
Which of the following is a true statement regarding the centering of the body part when using digital systems?
the part must be placed in the center of the plate or detector
The purpose of rotating the x-ray tube target is to
increase the heat capacity of the anode
What is the correct exposure time required to produce 50mAs when using a 200mA station?
0.25 seconds
Shape distortion is the result of
unequal magnification of the actual shape of the structure
Which of the following will be seen in the x-ray image if either the kVp or the mA is set too low for the projection?
quantum mottle
The greatest portion of the x-ray beam is made up of
bremsstrahlung-produced radiation
What is the purpose of the filament circuit?
supplies the heat required by the x-ray tube filament for thermionic emission of electrons
Which of the following will increase spatial resolution? 1. increase SID 2. increase OID 3. decrease in focal spot size
1 and 3
Which of the following x-ray generators produces the greatest amount of x-rays for the same exposure technique?
high frequency
Which control on the viewing station controls the density, or brightness, in the radiographic image?
window level
After the imaging plate is scanned in the CR reader and the image sent to storage, the phosphor is exposed to a __ to erase the anatomical image.
white light
The amount of detail or image sharpness in the digital image is termed
spatial resolution
What are the four essential requirements required for x-ray production?
a target, vacuum, electron source, and a high potential difference
Quantum mottle, or graininess in the radiographic image because of too few photons interacting with the body part will affect image quality by decreasing the
spatial resolution
The overall darkness, or blackness, within a radiographic image is referred to as
density
If the image were made using 500mA, 0.1second, and 75kVP, what would the mAs be for this exposure?
50 mAs
What is required to move the electron stream rapidly across the x-ray tube?
high potential difference
A smaller effective focal spot produces
greater image sharpness
Which of the following components is located on the low-voltage side of the x-ray circuit? 1. kVp selector 2. autotransformer 3. step-up transformer
1 and 2
Which of the following is the formula to calculate the heat produced by an exposure made on a three-phase generator?
mA x time (seconds) x 1.35
The greatest spatial resolution will be produced when the matrix is __ and the pixels are __.
large; small
The inverse square law states that the intensity of the x-ray beam is __ to the square of the distance.
inversely proportional
Which of the following is the function of the autotransformer? 1. provides the means for variable kVP selection 2. provides compensation for fluctuations in the incoming line voltage 3. supplies power to the other parts of the x-ray circuit
1, 2, and 3
What type of radiation is produced in the anode by the sudden slowing and directional change of an incoming electron?
bremsstrahlung radiation
The maximum heat capacity of the anode of the x-ray tube is rated in terms of
heat units
What is the primary advantage of x-ray filtration?
lowers patient dose
When is it necessary to differentiate tissues with similar tissue densities, which of the following image quality factors is most desirable?
high contrast
When tungsten atoms are heated, their outermost electrons are moved out of the atom in space. This principle is called
thermionic emission
A satisfactory radiograph is made using a 20mAs at 40in SID. How much mAs is needed to produce a similar radiograph at 60in SID?
45 mAs
The geometric factors that affect the formation of the image are: 1. SID 2. OID 3. focal spot
1, 2, and 3
The penetrating power of the x-ray beam is controlled by varying the
kilovoltage
A charge-coupled device is used in an indirect conversion DR system to
convert light to into an electrical signal
Which of the following pathologic conditions require a decrease in exposure technique? 1. multiple myeloma 2. emphysema 3. osteoporosis
1, 2, and 3
Into what three sections (subcircuits) in the x-ray circuit divided?
the low-voltage, filament, and high voltage circuit
Which of the following transformers reduces the voltage on the secondary side to provide an appropriate current to heat the filament?
step-down transformer
In which circuit is the step-up transformer located?
high-voltage
If the kVP is increased using the “15% rule”, an 80-kVP exposure would change to which of the following?
92 kVp
If the mA doubles, dose to the patient will
double
Which of the following would be considered inherent filtration? 1. oil 2. mirror 3. pyrex glass
1, 2, and 3
Contrast is directly influenced by: 1. SID 2. fog 3. collimation
2 and 3
Which of the following is located on the low-voltage side of the x-ray circuit and functions to measure the voltage output form the autotransformer?
exposure timer
