Busy. Please wait.
or

show password
Forgot Password?

Don't have an account?  Sign up 
or

Username is available taken
show password

why


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.


Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Don't know
Know
remaining cards
Save
0:01
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
Retries:
restart all cards
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Ch18 The Grid

Principles of Radiographic Imagine- Carlton

QuestionAnswer
The Grid Absorbs scatter, improves contrast
X-Ray Beam - as it passes through the body three things happen: Pass through unaffected or un-attenuated, Absorbed by the body photoelectric effect, interact and change direction (Comptons) - produces scatter (patient is source of scatter)
Effect of scatter on image contrast overall graying/fog, undercuts true image, DOES NOT produce image details, densities added in a negative sense
Scatter Contribution to patient dose and poor image quality major contributor, once produced, how can it be reduced to not degrade image quality? -GRIDS
Function of the grid IMPROVE CONTRAST
Function of the grid Higher kVp - grid efficiency goes DOWN
How does the grid work? Grid removes scatter by absorption (lead strips) improve contrast image, ideal all exit or remnant beam should pass through grid...
Exit X-Ray Beam Scattered photons- of no diagnostic value, add to overall density-graying effect (fog), decreases contrast = low contrast poor contrast resolution, the % of comptons increases
The amount of scatter radiation INCREASES when: Increase in patient thickness, Increase in field size, decrease in the atomic number of the tissue, such as soft tissue (electrons are most loosely bound)
Grid Use Thicker, larger body parts, procedures that require high kVp techniques, absorbs scatter radiation (cleans up image)
Grid Rules Thickness exceeds 10 cm, kVp exceeds 60 kvp
1913 Gustav Peter Bucky Original idea, crude design, thin lead strips
1920 Hollis Potter Lead strips running in one direction, thinner lead strips
Potter-Bucky Diaphragm Grid moves during exposure
Created by: lorperkins