Grid Errors
This occurs when the grid is placed upside down, often resulting in a significant loss of exposure to the IR
What is an upside-down grid error?
These two factors determine whether a grid should be used
What is 10cm of patient thickness and above 60kVp?
GCF stands for
What is the grid conversion factor?
This type of grid matches the divergence of the x-ray beam, reducing grid cut-off
What is a focused grid?
This grid error occurs when either the X-ray tube is angled or the grid itself is angled resulting in loss of exposure across the entire image
What is an off-level error?
These are the two primary purposes of using a grid in X-ray imaging
What is a reduction of scatter radiation and improved image contrast?
These two factors are used to calculate the grid ratio
What is height divided by distance?
Radiographic grids are constructed using these two materials in a variety of ways
What is lead strips and radiolucent interspace material (aluminum)?
The focal range for a parallel grid
What is infinity?
The use of a grid can improve the contrast of an image, but it also has this downside, particularly with High-ratio grids
What is an increased patient dose?
according to the Fauber textbook, a grid with an 8:1 ratio has this GCF
What is 4?
This type of grid moves in a circular motion during the exposure to blur the grid lines
What is an oscillating grid?
This grid error occurs when the SID is too short or too long for a selected grid resulting in a gradual loss of density
What is a focal range or off-focus error?
This is the main reason why a focused grid is preferred over a parallel grid for imaging thick tissue
What is the reduction of grid cutoff, and a decrease in the amount of scatter (more transmission x-ray)?
These two factors should be considered when selecting a grid and grid ratio
What is image quality and patient exposure?
This specialized grid design contains crossed lead strips in two directions to further reduce more scatter
What is a crossed or cross-hatched grid?
This grid error is only in CR, also known as the zebra pattern and this is the reason it occurs
What is the Moire effect?
a stationary grid causes this error, and the grid frequency matches the laser scanning frequencies
This is a way to prevent grid lines from becoming visible on an image when using high-frequency grids
What is the Potter-bucky diaphragm or moving grid mechanism?
When changing from a 24/3 grid to a 36/3 grid, this adjustment to mAs is required to maintain exposure to the image receptor
What is increasing mAs to compensate for a higher grid ratio?
This grid type is often used in portable X-rays and fluoroscopy because of its ease of use in varying positions and SIDs
What is a parallel (non-focused) grid?