RTBC-Principles of Exposure Flashcards
How is gross exposure error demonstrated in a digital image?
missing data points
The smallest exposure difference that can be detected and displayed by the imaging system is called:
contrast resolution
The fill factor of the direct radiography (DR) image receptor is the:
sensitive portion of the detector element compared to the non-sensitive portion
Which 3 mistakes are most likely to result in a histogram error artifact?
using incorrect collimation, processing a posteroanterior (PA) chest radiograph as a lateral chest, and processing a knee radiograph as a chest
Increasing the field-of-view (FOV) will have what effect on the pixel size?
increased pixel size
If a radiographer produced an image using an x-ray exposure that is below the dynamic range, the resulting image is expected to display:
quantum mottle
The spatial resolution of a radiography system is expressed in units of:
line pairs per millimeter (mm)
The formula to determine the magnification factor is:
magnification factor (MF) = source-to-image distance (SID) / source-to-object distance (SOD)
When source-to-image distance (SID) is increased, which change must be made to maintain image receptor (IR) exposure?
increase milliampere-seconds (mAs)
Digital image receptors with a large detector element (DEL) pitch will have:
low spatial resolution
An exposure is made using 5 milliampere-seconds (mAs) and 50 kilovoltage peak (kVp). What kVp is needed to double the exposure to the image receptor?
58 kVp
An increase in tube potential would increase image receptor exposure by increasing the:
number of photons in the beam and the penetrating ability of the beam
The ability to produce quality radiographs using a wide range of technical factors is called:
exposure latitude
Scatter radiation does NOT affect:
recorded spatial resolution
An underexposed image might produce an image artifact called:
noise and quantum mottle
What effect does using a large focal spot have on spatial resolution?
decreases spatial resolution
A radiographer acquires an image of the chest using 85 kilovoltage peak (kVp) and 5 milliampere-seconds (mAs). Her colleague acquires an image of the chest of the same patient using 90 kVp and 4 mAs. Both exposures resulted in an optimal image and an acceptable patient dose. This is an example of:
exposure latitude
Source-to-image distance (SID) refers to the distance from the:
focal spot target on the x-ray tube to the image receptor
During a series of mobile chest x-rays in the emergency room department, the technologist fails to adjust the kilovoltage peak (kVp) for a hypersthenic patient after their previous asthenic patient. This is likely to result in:
quantum mottle
Within digital radiography, bit depth is defined as the:
total number of gray shades that can be produced by the digital system
