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Questions and Answers
What does 'No grid =' equal?
What does 'No grid =' equal?
What is the value of 5:1?
What is the value of 5:1?
What is the value of 6:1?
What is the value of 6:1?
What is the value of 8:1?
What is the value of 8:1?
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What is the value of 10:1?
What is the value of 10:1?
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What is the value of 12:1?
What is the value of 12:1?
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What is the value of 16:1?
What is the value of 16:1?
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What is the grid ratio equation?
What is the grid ratio equation?
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If you're going from G to NG, what happens to your mAs?
If you're going from G to NG, what happens to your mAs?
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If you're going from NG to G, what do you do to your mAs?
If you're going from NG to G, what do you do to your mAs?
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If you're going from one grid ratio to a higher grid ratio, what do you do to your mAs?
If you're going from one grid ratio to a higher grid ratio, what do you do to your mAs?
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If you're going from one grid ratio to a lower grid ratio, what do you do to your mAs?
If you're going from one grid ratio to a lower grid ratio, what do you do to your mAs?
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What is the equation for calculating new mAs when changing from one grid to another?
What is the equation for calculating new mAs when changing from one grid to another?
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If you're going from no grid to a grid, you __ mAs by the factor # for specific grid.
If you're going from no grid to a grid, you __ mAs by the factor # for specific grid.
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If you're going from a grid to no grid, you __ mAs by the factor # for specific grid.
If you're going from a grid to no grid, you __ mAs by the factor # for specific grid.
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If you're just changing grids, what equation do you use?
If you're just changing grids, what equation do you use?
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If the grid frequency has a higher number, there are more strips so it absorbs more scatter.
If the grid frequency has a higher number, there are more strips so it absorbs more scatter.
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What is the contrast improvement factor (k) equation?
What is the contrast improvement factor (k) equation?
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What is the inverse square law definition?
What is the inverse square law definition?
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What is the inverse square law equation?
What is the inverse square law equation?
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What is the direct square law definition?
What is the direct square law definition?
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What is the direct square law equation?
What is the direct square law equation?
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What is the equation for new time station?
What is the equation for new time station?
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What is the equation for new mA station?
What is the equation for new mA station?
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What is the recommended increase in mAs for a wet plaster cast?
What is the recommended increase in mAs for a wet plaster cast?
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What is the recommended increase in mAs for a dry plaster cast?
What is the recommended increase in mAs for a dry plaster cast?
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What is the recommended increase in mAs for a fiberglass cast?
What is the recommended increase in mAs for a fiberglass cast?
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What law applies to SID changes?
What law applies to SID changes?
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For every 1 inch increase in SID, what should you do?
For every 1 inch increase in SID, what should you do?
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For every 2 inches decrease in SID, what should you do?
For every 2 inches decrease in SID, what should you do?
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At 34-38 inches SID, by what percentage should you decrease original mAs?
At 34-38 inches SID, by what percentage should you decrease original mAs?
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At 30-33 inches SID, by what percentage should you decrease original mAs?
At 30-33 inches SID, by what percentage should you decrease original mAs?
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For every 1 inch increase of OID, what should you do?
For every 1 inch increase of OID, what should you do?
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For every 2 inches decrease of OID, what should you do?
For every 2 inches decrease of OID, what should you do?
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For every 1 cm increase in tissue thickness, what should you do?
For every 1 cm increase in tissue thickness, what should you do?
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For every 1 cm decrease in tissue thickness, what should you do?
For every 1 cm decrease in tissue thickness, what should you do?
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What is the 15% rule?
What is the 15% rule?
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What kVp change is required to make a visual difference on a radiograph?
What kVp change is required to make a visual difference on a radiograph?
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Study Notes
Grid Conversion Factors
- No grid is denoted as 1.
- Common grid ratios include:
- 5:1
- 6:1
- 8:1
- 10:1
- 12:1
- 16:1, with increasing ratios requiring adjustments to mAs.
Grid Ratio Equation
- The grid ratio is calculated using the formula: H/D (height/distance).
mAs Adjustment Rules
- Decrease mAs when converting from Grid (G) to No Grid (NG).
- Increase mAs when converting from No Grid (NG) to Grid (G).
- Increase mAs when moving to a higher grid ratio.
- Decrease mAs when moving to a lower grid ratio.
- To calculate new mAs when changing grid types: New grid multiplier/Old grid multiplier x Old mAs = New mAs.
- When moving from no grid to a grid, multiply mAs by the factor corresponding to the specific grid.
- When moving from a grid to no grid, divide mAs by the factor corresponding to the specific grid.
Grid Frequency
- Higher grid frequency indicates more strips, thus absorbing more scatter.
Contrast Improvement Factor
- The equation for contrast improvement factor (k) is: k = contrast with grid/contrast without grid.
Inverse Square Law
- Definition: Intensity of the X-ray beam decreases inversely with the square of the distance from the source.
- Equation: I1/I2 = D2^2/D1^2.
Direct Square Law
- Definition: Used to determine new mAs when the distance changes.
- Equation: mAs1/mAs2 = D1^2/D2^2.
New mAs Equations
- New time station: mAs/mA = t.
- New mA station: mAs/t = mA.
Adjustments for Casting
- Wet plaster cast: Increase mAs by 150%.
- Dry plaster cast: Increase mAs by 100%.
- Fiberglass cast: Increase mAs by 50%.
SID Changes
- Changing SID will use the Direct Square Law.
- For every 1 inch increase in SID, increase mAs by 5%.
- For every 2 inches decrease in SID, decrease mAs by 5%.
- At 34"-38" SID, decrease original mAs by 30%.
- At 30"-33" SID, decrease original mAs by 50%.
OID and Tissue Thickness Adjustments
- For every 1 inch increase of OID, increase mAs by 10%.
- For every 2 inches decrease of OID, decrease mAs by 10%.
- For every 1cm increase in tissue thickness, increase mAs by 20%.
- For every 1cm decrease in tissue thickness, decrease mAs by 10%.
15% Rule
- Increasing kVp by 15% has the same effect as doubling mAs.
- Decreasing kVp by 15% has the same effect as halving mAs.
Minimum kVp Change for Visual Difference
- A 4-5 kVp change is required to achieve a visual difference on a radiograph.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz features flashcards focused on grid conversion factors and their corresponding equations. Each card provides a specific grid ratio and its numerical value, helping reinforce understanding of key mathematical concepts in this area. Perfect for students needing to master grid ratios for various applications.
