GRID CUT OFF LAB WITH NEAR DISTANCE AND WITH LATERAL DECENTERING

Posted on Updated on

  • The first image was taken with a SID of 100 cm and centered half an inch below the patellar apex. The kVp was 65 and the mAs was 3.8.
  • The next image was taken with an SID of 80 cm and since we were using a new distance we had to change our mAs based on the direct square law. mAs1/mAs2 * distance 1^2/ distance 2^2 our math obtained got us a new mAs of 2.432. since this option wasn’t attainable as a mAs value we used 2.6. as you can see the 2 images are very similar. With the original image having a density reading of 1.07 and the second film has a density reading of 1.04. As I looked up in Papp p.296 it mentioned how an increase in SID causes a decrease in optical density which doesn’t show in this image. Papp  however mentions that if the SID is changed by a factor of 2 the optical density changes by 2^2 of 4 times the density. So if this image were to have an SID of 50 instead of 80 we would see a much greater degree of density. Also the mAs plays the most significant role in optical density. As you know mAs depicts the quantity of x-ray photons that are produced. Therefore a greater mAs increases our optical density. A 25 – 30% change in mAs is required to change the optical density because of the human eye only being able to distinguish specific structures.
  • The next image we did was with a 100 cm SID and a lateral decentering by moving the centering point more towards the femur. Our original mAs was used here because we weren’t changing our distance. This type of grid problem is called OFF CENTERING. This causes the image to have a decrease in exposure over the entire film (GRID CUT OFF) therefore having less optical density across the entire film which can be seen by the bright whiteness in the image with hardly any density levels.
  • The last image we did was a combination of the 80 cm and lateral decentering. The 2.6 mAs was used here again because we were changing our distance. As you can see this image truly displays the grid cut off in beautiful fashion. The blurring of the image and terrible contrast levels indicate that the primary beam wasn’t positioned correctly and is the most noticeable off all the grid cut off exposures that we took.
Advertisements

63 thoughts on “GRID CUT OFF LAB WITH NEAR DISTANCE AND WITH LATERAL DECENTERING

    stock market soltions said:
    August 14, 2014 at 10:20 am

    Really informative blog.Much thanks again.
    stock market soltions

    Contractor Advertising Experts said:
    August 13, 2014 at 11:33 am

    Great, thanks for sharing this blog post. Cool.
    Contractor Advertising Experts – CONTRACTORS – Double your website traffic and never pay for advertising again! ContractorAdvertisingExperts.com

    web design company said:
    August 13, 2014 at 10:54 am

    I am so grateful for your article. Fantastic.
    web design

    Automotive Advertising said:
    August 13, 2014 at 7:20 am

    I really enjoy the article.Really looking forward to read more. Will read on…
    Automotive Advertising – Lotlinx is the best automotive advertising available. List your vehicles on 200 auto sites and draw 250% more car shoppers than Google Adwords for 65% less

    concert ear plug said:
    August 13, 2014 at 5:32 am

    Thanks for the article. Want more.
    concert ear plug – DownBeats is a cool brand of high fidelity hearing protection for concerts.

    symptom checker said:
    August 9, 2014 at 5:17 am

    Enjoyed every bit of your blog post.Thanks Again. Much obliged.
    symptom checker

    Cirrhosis Symptoms said:
    August 8, 2014 at 5:39 pm

    Really enjoyed this blog article.Really looking forward to read more. Want more.
    Cirrhosis Symptoms

    high blood pressure symptoms said:
    August 8, 2014 at 3:51 pm

    Im grateful for the blog article. Awesome.
    high blood pressure symptoms

    Lupus Symptoms said:
    August 8, 2014 at 2:09 pm

    Great article post.Much thanks again. Much obliged.
    Lupus Symptoms

    tick bite signs said:
    August 8, 2014 at 12:26 pm

    Im thankful for the post.Thanks Again. Really Cool.
    tick bite signs

    Kidney Failure Symptoms said:
    August 8, 2014 at 10:29 am

    Thanks-a-mundo for the blog post.Really thank you!
    Kidney Failure Symptoms

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s