Contrast
What is the product of IR contrast and subject contrast?
Radiographic contrast
What is the average build when referring to body habitus?
What is the main cause of motion blur?
Patient motion
What kind of IR should you use when imaging extremities and soft tissue?
A small pixel IR (70-100 micrometers)
What are some common physical artifacts that can occur with the IR?
Dust, scratches, and rough handling
What contrast is the difference in the x-ray beam after it passes through various tissues?
Subject Contrast
What happens when you use high kVp?
There is an increase in scatter radiation and more noise
True or False: can you control involuntary motion?
True, with short exposure times
Which type of compression shrinks the image file without losing any data so that radiograph image file can be restored exactly as the original?
Lossless compression
What is a ghost image?
A radiograph that appears on another radiograph due to incomplete erasure of a CR plate.
How does kVp affect subject contrast?
Lower kVp = more subject contrast
Higher kVp = less subject contrast
What refers to how tightly packed the atoms/molecules are in tissue?
Tissue Mass Density
What size focal spot reduces geometric blur?
Small
Which image compression makes image files much smaller by removing some image detail?
Lossy compression
What is interpolation?
The process of assigning a value to a dead pixel based on the recorded values of adjacent pixels
What influences IR contrast?
Detector characteristics (i.e. postprocessing algorithms, look-up tables, histograms, etc.), window width/level settings, dynamic range of the IR, and bit depth of the dels in the IR.
What does it mean if a tissue has a high effective atomic number?
That it will absorb more x-rays, thus appearing lighter on the image (it will be more radiopaque)
How would SID and OID decrease motion blur?
By having a long SID and short OID
What can Lossy compression not be used for?
Archiving
AI systems
CAD or Computer-aided detection
What is flat fielding?
A preprocessing software correction that is performed to equalize the response of each pixel and create a uniform x-ray beam.
What is the purpose of the image histogram?
Shows how often certain pixel values (brightness) appear in the image; each anatomical projection will have its own histogram
How can you fix backscatter radiation?
By shielding the IR
What can happen if your collimation is too wide or not centered?
Histogram errors and poor image quality
True or False: Proper partitioning is not required when imaging more than one body part on a single IR.
False
What can cause image artifacts when multiple images are placed on one IR?
Poor positioning and collimation