Topics in Radiography

CR Quality Control Summary

2013-05-11T10:11:00.001-07:00

A consistent quality control program goes a long way toward maintaining a high standard of image quality within your radiology department. The tests posted within this series are not all-inclusive for every CR system, but may provide as a good start for the beginning stages of any QC program. Variations may occur if your department utilizes a hard-copy laser printer and/or measurement tools at the QC station (or to include the radiologists' work station).

As a general rule of thumb, most CR vendors recommend designating one person as the quality control technologist. Other technologists may be trained in the event of an absence, but testing should be performed as consistently as possible to reduce variables.

Any QC test that does not meet specifications should first be repeated. After a repeat test fails, a qualified service professional should be contacted to troubleshoot the problem. Additionally, after any equipment repairs or replacement of parts, a new baseline should be established.

There may be additional troubleshooting to consider with equipment that might affect the QC testing results as well. If you know of any aspect of the x-ray machine used to perform QC testing that is inconsistent, such as line voltage, mA station linearity problems, or timer malfunctions, these can also be researched prior to contacting the CR reader's service professional. Ideally, the tests would be set up in the beginning to be performed on the most consistent equipment available. Imaging departments may also consider annual contracts with service professionals if consistency may be an issue.

Your quality control manual should be kept in a safe place, but accessible in the event of a state or JCAHO inspection. All results (even failing results) should be documented and maintained within the manual. You may also consider keeping records of service calls and documents related to equipment repair on hand for future analysis. Always watch for trends in test failures and use these trends to determine what service contracts and/or equipment repairs and replacement may best suit the needs of your department.

I hope you've found this series useful. Here is a summary of all of the tests covered:

CR Quality Control #1 - Screen Cleaning
CR Quality Control #2 - Creating a Baseline Phantom Image
CR Quality Control #3 - Exposure Indicator Calibration
CR Quality Control #4 - Contrast Evaluation
CR Quality Control #5 - Sharpness
CR Quality Control #6 - Shading Correction
CR Quality Control #7 - Laser Jitter
CR Quality Control #8 - Image Artifacts and Noise
CR Quality Control #9 - Exposure Linearity
CR Quality Control #10 - Residual Image Testing

CR Quality Control #10 – Residual Image Testing

2013-05-09T18:16:00.001-07:00

This test evaluates the CR reader’s erasure function and should be performed semi-annually. Each exposed image plate should be adequately erased during the processing cycle to prevent a residual image on the next image.

Procedure:

Erase your dedicated test IP
Place a lead apron on the floor of your x-ray room (use same room that baseline image was performed in)
Place test IP on lead apron
Place phantom on cassette (same orientation as baseline image)
Raise the x-ray tube to maximum height, center, and open collimation about 1" past edges of test IP
Expose the phantom at using twice the mAs value of the baseline image and process the image (or perform immediately following the system linearity test after the cassette has been erased on the exposure that was made at double the baseline).
Turn the phantom 180 degrees and place a radiopaque object in the center of the phantom
Expose at the normal baseline technique
Process the IP under “Contrast” menu selection

Results:

The processed image should appear normal compared to the baseline image, except that the phantom will be displayed upside down with the radiopaque object. There should be no evidence of an additional phantom pattern. If a residual image is present, re-test and call a service professional if the re-test does not eliminate the residual image.

Other posts in this series:

CR Quality Control #1 - Screen Cleaning
CR Quality Control #2 - Creating a Baseline Phantom Image
CR Quality Control #3 - Exposure Indicator Calibration
CR Quality Control #4 - Contrast Evaluation
CR Quality Control #5 - Sharpness
CR Quality Control #6 - Shading Correction
CR Quality Control #7 - Laser Jitter
CR Quality Control #8 - Image Artifacts and Noise
CR Quality Control #9 - Exposure Linearity

Shape Distortion

2013-05-07T19:08:00.000-07:00

One of the most fun courses I have taken and taught is exposure principles. This course typically introduces students to different types of distortion that can occur on the radiograph. Size distortion, otherwise known as simple distortion or magnification, occurs when OID is increased. The other type of distortion, shape distortion, can be broken down into two main categories; foreshortening and elongation.

Foreshortening is when the radiographic image measures shorter in one dimension than the actual object being radiographed. The only way this can happen is if the central ray and image receptor are perpendicular, and the object being radiographed is angled. This is demonstrated in the image below (courtesy of students in the Radiography Program at OCTS/KCTCS) by comparing the top left, undistorted image, to the middle two which were placed on 45 degree-angled sponges. This may also result in unequal magnification, where one side of the object may appear larger than the other due to differences in OID from one end of the angled part to the other.

Elongation is when the radiographic image appears longer than the object being radiographed. There are several situations where this can happen. If the central ray is perpendicular to the part, but the IR is angled, there will be more elongation with a greater increase in IR angle. If the part is parallel to the IR, but the x-ray tube is angled, elongation can occur as in the bottom left image below (45 degree tube angle to the part). Elongation can also occur when the x-ray tube is off-center to the part, even though the part may be parallel to the IR. This is caused by the divergence of the beam, and is demonstrated by the two images on the right below.

*note - there would be no difference between an off-centered x-ray tube with collimation opened to the part compared to a tube angle from the same starting point (as long as the tube does not move). Check this post out for more on that.

The image below is a similar experiment performed in one of my exposure principals labs. We observe the following using a quarter, a 2" sponge, and a 45 degree angled sponge:

Perpendicular CR to the coin (parallel to the IR) with a 2" OID
Coin parallel to IR on 2" sponge, but 45 degree tube angle
Tube returned to perpendicular to IR, but quarter is angled 45 degrees
CR angled 45 degrees (perpendicular to angled quarter)
CR angled half the part angle (demonstrating an isometric principle)

You'll notice very slight elongation in image 2 compared to the first. Image 3 is quite foreshortened, and image 4 has the most elongation. Image 5 is very useful for trauma views, and is illustrated with exams like the axial calcaneous and AP sacrum/coccyx. The tube is angled half of the part's angle to the IR. This reduces the effects of elongation as much as possible, so our exposure 5 measures the same as exposure 1.

CR Quality Control #9 - Exposure Linearity

2013-05-06T20:47:00.001-07:00

This test should be done semi-annually and tests for the CR system's ability to properly rescale images that are over or under exposed. It also measures accuracy of the exposure indicator and its ability to increase/decrease in relationship to the exposure value.

Procedure:

Erase your dedicated test IP
Place a lead apron on the floor of your x-ray room (use same room that baseline image was performed in)
Place test IP on lead apron
Place phantom on cassette (same orientation as baseline image)
Raise the x-ray tube to maximum height, center, and open collimation about 1" past edges of test IP
For all following exposures, annotate the technical factors used, exposure indicator, date, and which reader the image was processed on.

Exposure 1 - should be set with the same kVp as the baseline technique, but half the mAs. .

Exposure 2 - should be the same technical factors as the baseline exposure.

Exposure 3 - should be performed with the same kVp as the baseline technique, but double the mAs value.

Results:

The brightness of each of the three images should be the same. If there is variation, you may have a problem with the automatic rescaling function (click here to read more about automatic rescaling).

Exposure 1 should display a change in baseline exposure indicator to represent 1/2 the exposure +/- 20% (S# = baseline x 2, EI = baseline - 300, LgM = baseline - 0.3). Exposure 2 should be within +/- 20% of the baseline reading. Exposure 3 should display a change in baseline exposure indicator to represent a double in exposure value +/- 20% (S# = baseline x 0.5, EI = baseline + 300, LgM = baseline + 0.3).

Use the following formula to calculate percentage of change (click here for detailed instructions how to calculate percentage of increase or decrease):

new exposure indicator - baseline exposure indicator x 100
baseline exposure indicator

If variance is outside the +/- 20%, service personnel should be contacted.

Other posts in this series:

CR Quality Control #1 - Screen Cleaning
CR Quality Control #2 - Creating a Baseline Phantom Image
CR Quality Control #3 - Exposure Indicator Calibration
CR Quality Control #4 - Contrast Evaluation
CR Quality Control #5 - Sharpness
CR Quality Control #6 - Shading Correction
CR Quality Control #7 - Laser Jitter
CR Quality Control #8 - Image Artifacts and Noise
CR Quality Control #9 - Exposure Linearity
CR Quality Control #10 - Residual Image Testing

Radiographic Alternative for Opening Joint Spaces

2013-04-21T21:29:00.001-07:00

We all know the basics of opening joint spaces on our radiographs. Keep the joint space opening perpendicular to the image receptor while aligning the central ray directly to the joint. No problem... x-ray 101 right? But what about those joint spaces like wrists and ankles? You know, the ones where some of the radiologists say "you should have gotten more of the tibia (or forearm)!" Sometimes it's good to include a little extra - especially if your radiologists prefer it when there is obvious deformity.

The problem lies within x-ray beam geometry. I was going to make a video to demonstrate a basic principle in beam geometry, but Peter Gleeson did an exceptional job on his YouTube channel... watch his short video before we move on to some possible solutions.

Now that we know a tube angle does not change the distortion of an object because the x-ray source does not change position, we can evaluate our options... below, we have a traditional positioning setup for an AP ankle.

Sometimes we need a bit more of the distal tib-fib. One proposed solution I have seen is to simply move the joint to the bottom of the image receptor, while placing the central ray a few inches above the joint space. This accomplishes our goal of including more of the distal tibia, but can also close the ankle joint because it no longer lies directly in the central ray. The beam is divergent at the point of intersection with the joint.

I have seen the following method used in another state that does not have very strict guidelines on radiation protection. The tech would center to the joint space, but open the collimated field beyond the edge of the image receptor. I do NOT recommend this for ALARA purposes, but I thought I would throw this example in there because I have seen it before.

I propose we can take the best of both worlds with the following solution. Start out with the central ray over the joint space as in the previous example. Without moving the x-ray tube (longitudinal, transverse, or vertical) from its current location, angle it cephalic so the crosshair is a few inches proximal to the joint space. Collimate vertically so the field size does not go beyond the image receptor.

If you watched the video, you understand that the actual source of photons does not change with the tube angle. There is still a perpendicular path of x-ray photons opening the joint space, while we include more of the proximal tib-fib. The only disadvantage is there will be some elongation of the tibia near the periphery of the field of view. But also take note that the same amount of elongation would occur in the prior method due to the same beam divergence.

Don't believe me? Take any 3-dimensional object and place it directly under your perpendicular central ray. Open the collimation and angle the tube in either direction. You will notice (just as in the video) that the object's shadow does not move. As long as you do NOT move the tube from its current location prior to tube angulation, the beam divergence will be exactly the same with the tube angle as if you simply opened the collimation.

I should mention that the BEST way to avoid this whole scenario would be to have the physician order a tib-fib (or correct corresponding body part). But since we as technologists cannot order the exams, sometimes we have to make the best out of imperfect situations.

UGI Image Evaluation

2013-04-18T09:35:00.000-07:00

One of the things I used to do multiple times per day as a radiologic technologist was upper GI's. Though they're still being done quite a lot these days, I often forget how much effort we spent in x-ray school to learn how to properly tell them apart for hanging protocols. We can distinguish our views by evaluating three things:

Location of barium within the stomach
Location of air within stomach
The spatial relationship between the stomach and spine

If you take the first image below, it's easy to look at the radiograph and think it was performed supine, when in fact, it was exposed with the patient prone. The original x-ray may have been flipped horizontally upon first glance, but we are required to hang images in the anatomical position so it has been flipped. The fundus of the stomach is full of air, while the body contains barium. It is also superimposed over a non-rotated spine. This tells me the patient was prone.

On a double-contrast study, we need to remember how the anatomy lies in relationship to other structures to tell the difference. The fundus is superior to the body and also rests more posterior. I can tell it is prone because the air will rise to the most posterior anatomy when prone. I know this is not an upright exposure because while it would also demonstrate the barium in the body of the stomach, there would be more of a horizontal line separating the air/fluid level.

The lateral stomach view below demonstrates how the fundus is posterior to the body. I know different hospitals can have different hanging protocols for lateral views. So if I'm going to evaluate the image below to tell which lateral was performed, I could also reference the picture above knowing that the fundus lies to the patient's left side while the body and pylorus are more midline. If we remember that the air will rise while barium settles, it should be easy to differentiate between a right and left lateral. Since the barium is exiting the body and collecting in the pylorus and duodenum, we know that the patient's right side is down and a right lateral was performed.

Now, lets talk about oblique views. Still referencing the first image, we can tell that if an RPO is performed, the stomach should superimpose the spine, which is typically undesirable for UGI studies. The same would hold true for the opposite LAO. We almost always perform RAO or LPO views of the stomach to free the pylorus, body and duodenum from superimposition of the spine. That being said, look at the next image. We can tell it is LPO because the stomach is free of the spine, and the body is full of air. This is actually one of the radiologist's spot views. After the stomach drains some of the contrast, the barium coats and we can rotate the patient to allow air to accumulate at the juncton. Unfortunately, we cannot visualize the fundus, which is most likely full of barium, which would support our claim that this is an LPO.

*Tip: although the textbooks say "rotate 45 degrees," we should be mindful as technologists of the reasons for the rotation. In this case, the radiologist needs to visualize gastric emptying function in profile while not being superimposed by the spine. Some times we need to rotate more or less depending on patient body habitus, so keep an eye on the fluoro monitor when assisting the patient while rotating. If you rotate 45 degrees, it may not be enough to adequately allow for an optimum view. When contrast is involved, we need to be efficient, so we don't want to stand there waiting for the radiologist to tell us to turn the patient more while we're missing a good opportunity to image the stomach emptying.

Compared to the image above, the next set of images differs in that the barium is in the body, while air is in the fundus. This tells us the fundus is superior to the body, but we also know it's an oblique due to several give-aways. The fundus and body are free of superimposition of the spine, and you can also notice rotation of the spine itself. For these reasons, we know these are RAO views. They were taken in the position of the bottom left image below (where the fundus is closer to the x-ray tube/superior to the rest of the stomach). The images were then flipped horizontally to represent anatomical position like in the bottom right image.

Evaluating UGI images can be somewhat confusing at first, but once you get it, it's like riding a bike. If you can visualize how the stomach lies within the abdominal cavity, it's not so difficult. Acquiring that knowledge early on in your studies will make a huge difference later when you're in the middle of a procedure.

*if you like the virtual images I posted, check out the interactive anatomy site, https://www.biodigitalhuman.com/. There is an interactive anatomy skeleton with all body tissues which gives you the opportunity to isolate tissues of interest, rotate, zoom, and a few other helpful tools.

Radiographic Sitzmarker Study

2013-04-03T11:03:00.000-07:00

Unless you work in a hospital that routinely treats pediatrics or you have been around the world of radiography for a while, you may not have seen a Sitzmarker test. This exam is done for patients who have experienced chronic constipation, and may be used to support a number of gastrointestinal disorders.

Procedure: A capsule is swallowed containing several metal rings encased in plastic. Once the capsule dissolves, the rings disperse and can be followed through the GI tract.

I have seen varying routines depending upon radiologists' preference at different imaging departments. The patient could return every day (approximately the same time of day) for a follow-up KUB, and I have seen them spaced out as far as 5 days. The dictation should note the difference in location of the rings, as well as the amount of time for motility to allow the rings to pass.

The normal GI tract should evacuate the rings within 2-3 days. Other disease processes could make the rings take more or less time, but most frequent findings are with constipation where it delays passage for more than 5 days.

Radiography School Checklist

2013-03-31T09:41:00.000-07:00

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

CR Quality Control #8 - Image Artifacts and Noise

2013-03-29T17:29:00.000-07:00

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:

Erase your dedicated test IP
Place a lead apron on the floor of your x-ray room (use same room that baseline image was performed in)
Place test IP on lead apron
Place phantom on cassette (same orientation as baseline image)
Raise the x-ray tube to maximum height, center, and open collimation about 1" past edges of test IP
Use the same technical factors that produced the baseline image (check monthly log for exposure factors) and make an exposure
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

Other posts in this series:

CR Quality Control #7 - Laser Jitter

2013-03-22T19:47:00.001-07:00

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:

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

Other posts in this series:

CR Quality Control #6 - Shading Correction

2013-03-21T05:22:00.000-07:00

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:

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

Other posts in this series:

Improved Portable Chest X-Rays with Grids

2013-03-20T17:04:00.000-07:00

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.

CR Quality Control #5 - Sharpness

2013-03-19T16:16:00.000-07:00

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:

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

Other posts in this series:

Pinterest... Doing it Right

2013-03-17T10:00:00.001-07:00

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 :-)

CR Quality Control #4 – Contrast Evaluation

2013-02-05T13:36:00.002-08:00

Perform this test to see if the CR’s ability to visualize scale of contrast is comparable to the initial baseline image. You can evaluate the contrast for hard copy film, the CR QC station, and the radiologist’s reading station.

Procedure:

Erase your dedicated test IP
Place a lead apron on the floor of your x-ray room (use same room that baseline image was performed in)
Place test IP on lead apron
Place phantom on cassette (same orientation as baseline image)
Raise the x-ray tube to maximum height, center, and open collimation about 1" past edges of test IP
Use the same technical factors that produced the baseline image (check monthly log for exposure factors) and make an exposure
Annotate exposure indicator number and which CR reader was used
Visually compare the contrast areas on the new exposure of the phantom with the contrast areas on the baseline image in your archive (*note – the brightness and contrast settings on your viewing monitors should be the same as when the baseline image was evaluated)

Evaluation:

The contrast area on the left (for my phantom) consists of two circles of Pb (lead) equivalent material. The outer circle is 0.15 mm Pb, while the inner is 0.5 mm Pb.

The contrast area on the right consists of an empty hole, while the inner circle is made of 0.7 mm Cu (copper).

A simple visual comparison is enough to determine a pass/fail result. Keep a few things in mind when looking at the images:

The monitors will degrade over time, which can provide some display inconsistency. It is advised to observe both the QC monitor and the radiologist’s monitor for variation. If only one of the monitor’s display appears to be sub-par, while the other appears optimum, consider replacing the sub-par monitor. However, if both monitors appear sub-par, it is more likely due to a reduced contrast performance of the reader, and a service engineer should be notified.

If you are comparing using hard-copy film, you can use a densitometer to get a precise density difference measurement from each contrast area, comparing the outer circles to the inner.

Other posts in this series:

CR Quality Control #3 - Exposure Indicator Calibration

2013-02-02T13:23:00.003-08:00

Two primary things can cause the exposure indicator to vary during regular operating procedures; the photomultiplier tube can be out of specifications as well as the exposure output of the x-ray tube. In order to identify early variances, we must perform monthly tests to ensure proper calibration.

Supplies needed:

Test phantom
Lead apron
Monthly log of prior tests
Most recent baseline exposure (see "Creating a Baseline Phantom Image")

Procedure:

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

Results:

The exposure indicator should match or be very close to that of the baseline reading. If it does not match, you need to calculate the percentage of difference. Acceptable variation is +/- 20%. Use this formula to calculate:

If results are outside 20% variation, repeat the exposure. If the second exposure is outside variation, there could possibly be a problem with the generator or the CR reader which would warrant a service call. Once the problem has been identified and corrected, a new baseline must be established, and monthly testing needs to continue with comparisons to the new baseline. Note the new exposure indicator and date on the image and in the QC log.

Note - "exposure indicator" refers to a general term that varies between manufacturer (S#, EI, LgM, etc.)

Other posts in this series:

Introducing the Radiography Cafe!

2013-01-29T21:39:00.000-08:00

I've been wanting to find a better way for students, radiographers and instructors to get together and discuss ideas for a long time. In fact, it was the main goal behind the beginnings of this blog. Unfortunately, the comment section of a blog has some limited capacity for discussion. But now, technology has progressed to the point where someone with virtually no experience building a website can construct a user forum in minutes.

I am pleased to bring you the Radiography Cafe (RadiographyCafe.freeforums.org)!

Here you will find a ground-level forum that I wish to populate with lots of great discussion about anything and everything radiography. Since I am currently alone as administrator and moderator, please forgive me if I do not immediately respond to private messages or some of the initial posts as I will be doing this in my free time. I am, however, seeking people interested in assisting with forum moderation and maintenance, so if you're interested, please register on the forum and send me a private message.

I hope this can be a valuable resource... and even if it doesn't turn out that way, I hope it can be a fun environment to get to know your fellow radiographer/student/instructor.

CR Quality Control #2 - Creating a Baseline Phantom Image

2013-01-23T12:58:00.000-08:00

Before you begin your routine monthly/semi-annual/annual radiographic equipment testing, you need to have a baseline image to compare it to. The idea is that when you perform your actual tests in the future, you will not be able to tell whether or not your results are good or bad without having something to reference. This method provides the measurable standard for calculations that will need to be performed later during testing.

We use one phantom with multiple test tools within it at the place I work now. Select a medium-range kVp (I use 80 kVp). You will also need an x-ray room with relatively low mA stations, a lead apron, and some kind of log to record your results in. The vendor we purchased our phantom from provided us with a log. We also took a brand new 14x17 cassette out of circulation and only use it for QC testing to reduce variability (and keep it with your phantom).

Procedure:

Erase your test CR cassette before any exposures are made.
Raise your x-ray tube to its maximum height and keep it above the floor (not directly over the table).
Place a lead apron on the floor directly under your central ray.
Place your CR cassette on top of the lead apron (without a grid cap).
Place your phantom on top of the cassette - make sure to orient the top of the phantom to the top of the cassette and keep this orientation for all future testing.
Center your x-ray beam to the phantom and cassette, leaving about one inch of light field outside the borders and onto the lead apron.
Select 80 kVp and 100 mA. Try also setting 0.10 seconds and make an exposure.
Process the image and note the exposure indicator (S#, Exposure Index, or LgM)
If needed, adjust the time station so that you achieve an optimum exposure indicator number (*see note for proper levels of exposure indicator numbers)
Once you have the disired technical factors, annotate the date, exposure factors, and "baseline image" and send to PACS - your PACS administrator can create a folder for QC images
Create an individual baseline image for each CR reader and log results.

*When attempting to expose your baseline image for optimum exposure indicator, you may need to consult the manufacturer guidelines or your physicist. As a starting point, you can use the following:

S# = 200... if you double your time (or overall mAs), you will half your S#
Exposure Index (EI) = 1800... if you double your time (or overall mAs), you will add 300 to your EI
LgM = 2.1... if you double your time (or overall mAs), you will add 0.3 to your LgM

The Baseline exposure log should include the following information that will be referred to for later testing:

Room number (that the test exposures are made in)
SID
Image plate identification number
kVp
mA
time station
Target exposure indicator number (this is your baseline S#, EI, or LgM)
CR reader (number your readers if you have not already done so)

Keep your logs, test cassette and phantom/s in a safe place away from your other equipment to minimize risk of circulation with other supplies. Next, we'll get into some of the monthly tests.

Other posts in this series:

Employment Survey Results

2013-01-02T08:54:00.000-08:00

Back in October of 2012, I posted a survey about the employment situation across the country and asked six questions relating to the job market aimed at new graduates from radiography school. With any survey, the more responses received, the more accurate the results. I received 30 responses to my questions, and here they are:

The results were anonymized, but it seems there are a range of responses across the board. I know the job market is not as good as when I graduated from x-ray school in 2000, but if these responses are representative of the national average, I have seen worse.

In my book, Becoming a Radiologic Technologist, I explained the criteria that a radiography program must have 75% of its graduates employed (in any tech job) within 6 months of graduation. I would be interested in speaking to any of my readers who represent JRCERT to learn more about the re-accreditation process and statistics about radiography program probation due to low employment statistics.

Until then, it seems that the market is competitive. Like any field, that's not to say every graduate is guaranteed a job right out of school, or even a full-time day job. There are positions available, but keep an open mind to the possibility that you may need to relocate, accept undesirable shifts, or have some delays in finding an ideal position. I wouldn't discourage anyone from seeking an education in radiography, but you need to love what you're doing and be prepared for competition.

CR Quality Control #1 – Screen Cleaning

2013-01-01T15:51:00.000-08:00

One of the most important, yet sometimes underperformed activities we can do to keep our image quality high is routine cleaning of image plate phosphor screens. Each CR system manufacturer will recommend a schedule for routine cleaning of IP’s, but I tend to think that a monthly schedule serves my department well. This may vary depending on your department’s patient volume and usage.

How to clean: Remove image plate from cassette holder. Inspect in good lighting to identify any potential dust, scratches, or flaking off of the phosphor layer (see images below) that may produce artifacts. Always replace the IP if needed – discuss the need for replacement with a radiologist and/or your department manager if you are uncertain whether or not the plate has enough damage.

Take a non-abrasive cloth or gauze and dampen it with screen cleaner (see manufacturer’s guidelines for type of recommended cleaner). Wipe in small circular motions until the entire screen has been properly wiped down and inspect for dust. Make sure that you use something that does not leave a lint residue. Do not place cleaner directly on image plate.

Let each screen dry, being careful not to rest the phosphor side of the screen down. Most cleaners are alcohol-based and should dry rather quickly. Make sure each plate is completely dry before re-inserting into the cassette.

Each IP at my facility (we are using FUJI CR) has a barcode that can be catalogued and records can be kept logging which plates were cleaned, when they were cleaned, and by whom. It should also be noted when any damage to an image plate is identified, as well as if a plate gets replaced. I chose a rather worn cassette for the following image because you should also visually inspect the cassette. Some times the hinges that hold the image plate inside the cassette become loose leaving the plate to fall to the floor and become scratched. It’s much cheaper to replace hinges on a cassette than to replace the phosphor screen.

Any radiologist will tell you if artifacts are seen on your images, but monthly cleaning of the image plates should keep them to a minimum. This is one of the easier activities any rad tech or student can perform that can be extremely valuable to image quality in your department. Normal wear and tear will occur as the image plates are processed, but keeping a log over time should help you predict how often you will need to replace screens and how your department should budget for them.

Other posts in this series:

Merry Christmas!

2012-12-24T09:31:00.000-08:00

You can download the Kindle version of my book, "Becoming a Radiologic Technologist" for FREE on Christmas Day. Merry Christmas everyone!

Why is there a Barium Shortage?

2012-12-16T10:41:00.000-08:00

For the last few months, our hospital has had trouble acquiring barium for our GI studies. When I asked our suppliers why there has been such an issue, they told me that all barium was on back-order. "Yeah right," I thought... when the heck has there ever been a problem getting barium? I thought they might have forgotten to order some and they didn't want to own up to it. The problem was that it kept happening! We got to the point where we had scheduled patients, but not enough barium to complete the studies for the day. There were several times that we used a courier to deliver supplies from one of our other hospitals within the organization, but eventually, they stopped allowing us to do that after some time because they had also run out. Why is this happening now, and what is causing it?

Well, yesterday, I was speaking to one of our radiologists, and he informed me that there was a depletion of barite from the world's largest mines... the earth is simply running out! I thought he was joking at first, but he encouraged me to "google" it. I found some interesting things:

Most of my first search included headlines from news articles across the world stating things like "hospital forced to stop barium studies." I guess I'm not the only one experiencing this. I also ran across this letter from Bracco, the largest supplier of barium sulfate for radiology exam purposes. It goes on to list all of the produces which there is a shortage of, and also explains that they are attempting to fulfill back ordered products as soon as possible. Among the list of products happens to be every single one my hospital uses for GI studies. I also ran across a list of current drug shortages from the American Society of Health System Pharmacists which confirms the significance of the shortages.

Then I ran across this article, which explains that due to increased safety regulations in barite mines in China, the volume of barite production has fallen to about 25% of what it once was. China is responsible for over 51% of the barite mining in the world. India is the next largest supplier at about 14% The U.S. is responsible for about 9% while Morocco mines about 7%. The rest of the world together supplies about 19% of the global supply.

The barite reduction is said to mainly be caused by increased safety regulations in China's mines. There's also the fact that as the mines get deeper and drilling sites expand, there is increased cost for getting the barite to export ports. If you dig deep (no pun intended) into some of the articles on google, you can find comments from people who claim to be associated with these mining companies (mainly from China and India) who are also stating that the world's supply of barite is being rapidly depleted, and propose that this is another reason for the reduction in barium sulfate production. It is difficult, however, to find concrete sources for that information with the amount of searching I have done, but it's interesting nonetheless. Other comments advise the world to begin looking for other materials that can perform the same job that barium sulfate currently does, which would lend some credibility to the notion that it is being depleted.

Could we be entering an era of no barium studies? It's quite possible, although we will simply have to use another form of contrast media for the current exams we are performing with barium. There's always water soluble contrast... and there's potentially a lot of money to be made for any manufacturer out there that can come up with a cheap and plentiful alternative to barium (I'll accept a 2% credit on all profits for giving you the idea). I would love to hear what everyone is using as their barium runs out, along with the pros and cons of each. Feel free to let me know in the comments!

Radiography Discussion Resources

2012-11-05T08:38:00.000-08:00

Have you ever had a burning question about something radiography-related and didn't know where to turn? You're not alone! There are others like you who are interested in sharing ideas and providing information. I have made many connections through discussion forums and websites that are strictly radiography-related, and it's important to have some resources to go to when you need some input, don't have answers to questions, or if you're willing to share your knowledge. Here are some of the best discussion resources I have found on the web:

Aunt Minnie is a great site for anything from multi-modality news to job boards to discussion forums. This is by far one of the largest sites with the widest range of contributors that I have come across. If you're looking for research, a large number of technologists involved, or even CE credits, this is the place to start.

Wiki Radiography is growing, and already has many resources specific to radiography. I like this one because you will always get a direct answer from a technologist. There are techs from all over the world participating here including the U.S., U.K. and Australia. Check out the many great articles and radiographic anatomy resources.

The Radiographer's Alliance is one that I have just recently browsed, but will become more involved in quickly. With the welcoming description "the place where radiographers can really talk," I'm already feeling welcome.

Radiopedia is another large site with literally tons of information. You will find contributors from radiologists to every modality of imaging. There are free lessons, tutorials, case studies, and articles posted here among the many discussion boards. If you have a lot of brain space waiting to be occupied by radiology-specific info, start here!

Radiology Forums is a site that has recently been introduced to me... it's still growing, but I see a lot of promise here. Any place that is willing to provide a safe environment for discussion is okay in my book.

If you are looking for answers not found on any of these resources, you can always check out Yahoo Answers. You may run across some opinions that are rather ridiculous and misinformed, but every once in a while you'll strike gold. I like it because those who are willing to answer questions with any integrity will provide a resource/link to support their answer.

Of course, I always like to hear from my readers and you can get involved here on my blog in the comments, or connect with me on Facebook, Twitter, Linked In, and even Pinterest.

Radiography Employment Survey

2012-10-28T08:49:00.000-07:00

I have spent a lot of time talking about the job market, tips for employment, and even health care politics. I even published a book that goes into these topics in greater detail based off information and statistics from reputable sources like JRCERT (accredits radiography schools) and the U.S. Department of Labor Statistics. Since my book has been published, I have received a lot of comments/dialogue about the job market in particular in various regions of the country - even from people who have not read my book and assume that I take a particular stance on whether or not the reader should be jumping into a career in radiography. The comments are vast and can even be conflicting... in other words, one person would claim there are tons of jobs available if you are willing to travel, take a casual position, work nights, etc. Others claim that there are next to zero options for them in their situation.

When I wrote my book, my goal was for it to be informative. I discuss employment from a statistical standpoint with verifiable sources. I realize there are some elements that quoting national statistics will simply overlook, and I have encouraged anyone purchasing my book to perform their own market research in the region they wish to work as a radiographer due to the competitive nature of jobs in our country today. That is why I would like to conduct an informal survey. I want to give YOU a voice as well.

A large percentage of readers of my blog are students or new grads from the United States. If this applies to you, I would like to encourage you to participate in this survey. I can quote statistics until the sun goes down, and many of my readers do not have other sources for information in the health care setting. So regardless if your experiences finding employment in radiography were positive or negative, I would love to hear about them and share them with my readers. Below, I have six multiple choice questions and an optional essay response question that I will leave open until January 1 2013. I wanted to make it short and sweet, but if it's still too time consuming, feel free to leave a comment to this post. Thank you in advance for those of you who can participate. Please be respectful of others with your comments.

Create your free online surveys with SurveyMonkey, the world's leading questionnaire tool.

Topics in Radiography

CR Quality Control Summary

CR Quality Control #10 – Residual Image Testing

Shape Distortion

CR Quality Control #9 - Exposure Linearity

Radiographic Alternative for Opening Joint Spaces

UGI Image Evaluation

Radiographic Sitzmarker Study

Radiography School Checklist

CR Quality Control #8 - Image Artifacts and Noise

CR Quality Control #7 - Laser Jitter

CR Quality Control #6 - Shading Correction

Improved Portable Chest X-Rays with Grids

CR Quality Control #5 - Sharpness

Pinterest... Doing it Right

CR Quality Control #4 – Contrast Evaluation

CR Quality Control #3 - Exposure Indicator Calibration

Introducing the Radiography Cafe!

CR Quality Control #2 - Creating a Baseline Phantom Image

Employment Survey Results

CR Quality Control #1 – Screen Cleaning

Merry Christmas!

Why is there a Barium Shortage?

Radiography Discussion Resources

Radiography Employment Survey

Top 5 Difficult Questions from Patients