Sunday, March 31, 2013

Radiography School Checklist

Happy Easter!  Here's a free download (updated) for anyone who is thinking about going to radiography school.  Make sure to research your local job market in addition to completing this checklist.

Click on the image to download


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Friday, March 29, 2013

CR Quality Control #8 - Image Artifacts and Noise

Perform this test monthly along with other monthly QC or as needed.  Your radiologists will usually inform you they are seeing artifacts on images before technologists notice them due to the high resolution of their screens and necessity to magnify images.  No additional exposures are necessary, and you may use the test images from any of the other tests.  This can test for the presence of noise or artifacts originating from the image plate, CR reader, or the hardcopy laser printer.  Example digital images from an actual exam:





As you can see, the artifacts are quite visible once magnified.  Just imagine how much more visible these artifacts would be on a high resolution monitor in front of the radiologist!

Procedure:
  1. Erase your dedicated test IP
  2. Place a lead apron on the floor of your x-ray room (use same room that baseline image was performed in)
  3. Place test IP on lead apron
  4. Place phantom on cassette (same orientation as baseline image)
  5. Raise the x-ray tube to maximum height, center, and open collimation about 1" past edges of test IP
  6. Use the same technical factors that produced the baseline image (check monthly log for exposure factors) and make an exposure
  7. Annotate exposure indicator number and which CR reader was used and ensure that it is within specifications.
Things to look for:
  • Grainy appearance of image - ensure that the Exposure Indicator is within specifications - could indicate mottle produced by improper exposure factors or incorrect physical setup
  • Inspect the image plate for debris or scratches that can produce artifacts with reduced density on your radiographs
  • A longitudinal white line across the entire image indicates dust on the light guide.  Have a service rep clean the reader
  • Any artifacts on a hard-copy film that may be caused by the printer (present on film, but not on digital image)
  • Variations in brightness across the digital image.  This could be specific to the monitor you are viewing and can be cross-referenced with another viewing station to isolate the problem
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Friday, March 22, 2013

CR Quality Control #7 - Laser Jitter

This test will determine whether the mechanical motion of the image plate, laser, and optics are consistent in the transport system of the CR reader.  It should be performed monthly, or after any service to the CR reader.

Procedure:

  1. Erase your dedicated test IP
  2. Place a lead apron on the floor of your x-ray room (use same room that baseline image was performed in)
  3. Place test IP on lead apron
  4. Place phantom on cassette (same orientation as baseline image)
  5. Raise the x-ray tube to maximum height, center, and open collimation about 1" past edges of test IP
  6. Use the same technical factors that produced the baseline image (check monthly log for exposure factors) and make an exposure
  7. Annotate exposure indicator number and which CR reader was used
  8. Print a hard-copy image on the laser printer
  9. Inspect the edges of the "T" in the middle of the phantom for jagged edges

According to FUJI's FCR QA 1 Shot Phantom manual, a certain degree of jagged edges is expected, but under 2X magnification on the QC or reading stations, they should not be visible to the human eye.  Compare the new image to the baseline phantom image.

If the jagged edges appear at the QC station and the laser film, the reader should be serviced.  However, if the jagged edges only appear on the hard copy, but not the QC station, there may be a problem with the laser printer.  Call service and record results on the monthly log.


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Thursday, March 21, 2013

CR Quality Control #6 - Shading Correction

This test checks to see if the CR scanning laser has uniform intensity across the entire image plate.  It should be performed monthly, or after service to the CR reader's light guide and/or optics.  While this test can be visibly inspected on digital monitors, it can only be quantitatively performed using hard-copy dry laser film with a densitometer.

Procedure:
  1. Erase your dedicated test IP
  2. Place a lead apron on the floor of your x-ray room (use same room that baseline image was performed in)
  3. Place test IP on lead apron
  4. Place phantom on cassette (same orientation as baseline image)
  5. Raise the x-ray tube to maximum height, center, and open collimation about 1" past edges of test IP
  6. Use the same technical factors that produced the baseline image (check monthly log for exposure factors) and make an exposure
  7. Annotate exposure indicator number and which CR reader was used
  8. Print a hard-copy of the phantom image
  9. Measure the optical density of the middle measuring point and document
  10. Measure the optical density of the outer-lying points and document
 

The acceptable variance in optical density of the outer two measuring points (compared to the center) is +/- 10%.  If measurements exceed this variance, repeat the test.  Call a service engineer if still outside acceptable standards.


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Wednesday, March 20, 2013

Improved Portable Chest X-Rays with Grids

I know I have posted about this topics before, but I would like to stay on this soap box for a while because I know that education still needs to occur regarding dose reduction techniques using CR and DR equipment.  Over the past several years since I began writing here, a lot of improvements have been made in the materials used and sensitivity of our digital radiography equipment, which reduces radiation dose significantly.  For some reason, either technology has progressed far faster than the continuing education of our peers, or technologists are resisting the pace of change occurring with imaging technology, and grids are not being used as they should.

In 2008, I had the pleasure of attending a workshop on digital radiography with lecturers Barry Burns, James Barba, and Andrew Woodward at the University of North Carolina.  After putting to practice the principles taught there, everything has held true over the last 5 years.  I'm going to show you two recent x-rays of the same patient which support the information presented.  The first was done without a grid and the second with a grid.  Keep in mind that the patient was just over 100 lbs, so very small in relationship to the average patient size.


85 kVp 5 mAs, non-grid, optimum exposure indicator



120 kVp 3.2 mAs, 8:1 grid, optimum exposure indicator


Both of these images were taken using some very aged FUJI CR image plates (see image plate chipping damage on top of the images - I hear they're being replaced).  They were taken by different technologists within the same week.  The non-grid film was taken in an ICU bed prior to portacath insertion, while the gridded image was obviously taken after.

Advantages:

  • Higher quality beam = more uniformly penetrating.  You can not only see thoracic spine through the mediastinum, but there is also better visualization of the central line, chest tube and NG tube.  It is difficult to see below the diaphragm or even through the mediastinum at lower kVp without a grid.
  • Higher kVp and lower mAs = lower patient dose.  With higher kVp, the entrance skin exposure is lower because there is more energy behind the photons pushing them through the patient anatomy.  The lower mAs value speaks for itself as mAs is directly proportional to intensity.
Disadvantages (trying hard to come up with any):
  • Some technologists struggle with grid cutoff on portable chest exams.  Strategies for reducing cutoff include perpendicular beam, using lengthwise orientation when possible, or utilizing a short-dimension grid.  Sliding the patient up in the bed prior to sitting the head of the bed up is essential (read "Lordotic Much?" at the end of this post).  In other words, there is less positioning latitude.
In my opinion, there is a clear choice.  When we can prioritize patient dose while improving image quality, why would anyone want to do otherwise?  Of course, I'm here to learn as well as to publish my opinion, so I welcome any comments, suggestions, criticism, etc.

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Tuesday, March 19, 2013

CR Quality Control #5 - Sharpness

This test ensures the display and image processing systems are operating within normal specifications.  This test should be performed monthly or after servicing of the CR reader.

Procedure:
  1. Erase your dedicated test IP
  2. Place a lead apron on the floor of your x-ray room (use same room that baseline image was performed in)
  3. Place test IP on lead apron
  4. Place phantom on cassette (same orientation as baseline image)
  5. Raise the x-ray tube to maximum height, center, and open collimation about 1" past edges of test IP
  6. Use the same technical factors that produced the baseline image (check monthly log for exposure factors) and make an exposure
  7. Annotate exposure indicator number and which CR reader was used
  8. Compare the line pairs/mm on the new image to that of the baseline phantom image

According to the user manual for this phantom, the copper filter within this phantom produces a large amount of scatter which will reduce the actual visibility of detail in our test image, so it shouldn't be used to determine system resolution.  My hospital will need a stand-alone line-pair resolution test pattern for that determination, so check your manual to see if the same is true of your phantom.

When at all possible, use the magnification tool for each workstation to compare the new image to the baseline.  Record any variances, and if a moire pattern is observed, you may need to repeat your phantom exposure prior to recording your observations.



Note: the image on my blog is dramatically reduced in resolution compared to that visible by the radiologist's monitor in the reading room.


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Sunday, March 17, 2013

Pinterest... Doing it Right

With the rise of new social media that seems to occur almost every day, I find it difficult to find the time stay current on all the rules and regulations that are set for each.  I recently began integrating Pinterest with my other social media because of how easy it allows me to share the image-based content we are all interested in.  After using it for a while though, I have noticed some definite do's and don'ts when pinning images to one of my boards.  

The main issue I see happening is failure to credit the original website/author/photographer.  If 10,000 pinners "repin" something of mine, and I'm linked to the original site where I found the image, all it will do is increase traffic to that site which should make the owner very happy.  However, if I pin or repin an image from a location other the owner's site, then the original author will not get credit whenever other people view and/or repin.  

This has other repercussions as well.  If I (the image seeker) like the image and there is more relevant content on the original site I may be interest in, I may never see it because I don't have the appropriate source linked to the image I like. It will also eventually frustrate some of my board followers.  Even though they may love the images I'm placing on my boards, they will have to click through a few times searching for the original image.  For instance, I repin something from another board I saw, and that person repinned it from someone who didn't site the original source as well, but pinned it from someone who did.  Going through 3 or 4 extra click-throughs to find the original source doesn't sound like a lot of time to waste, but your follower may choose to simply unfollow you and follow the person who sited the source image... you lose followers and may even see yourself getting reported as Pinterest users become more savvy.

Another important guideline to follow while pinning to your own board is don’t post directly from other image databases.  Google images for example, like Pinterest, has created a database of images that came from an outside source.  While browsing through Google images, take the time to click through to the original site where google extracted the image before pinning it. It may take one or two extra clicks to follow the image to it's origins, but your followers will appreciate it and you can rest easy at night knowing you are pinning ethically.

I haven't heard of any copyright issues with this, although I think there may be some potential.  Social media like Pinterest improves convenience for the user, but because it's so new, the legal system hasn't really caught up to some of the possibilities that can occur with it.  Responsible sites have suggestions on etiquette that should steer users clear of potential copyright or plagiarism issues.  For those and other useful guidelines, you should be able to find them rather easily for each respective social media site.  Click here to see Pinterest's guide to etiquette.

As suggested by the Pinterest etiquette guide, if you know someone is pinning improperly without siting the original source, feel free to leave a comment letting them know.  You don’t need to be rude, but you could say something like “I wish I knew where the original site was for this image.”

Would you like to follow me on Pinterest?  CLICK HERE :-)





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