Up for Discussion...

I'm finding it more and more common for facilities all across the country to require that all PA chests be attempted lengthwise first, regardless of whether or not you believe the lungs will fit on a lengthwise film. If you are reading this and your facility does this, I would be interested in learning about the reason for it.

I have heard that some Radiologists prefer this because they can get a better assessment of heart size when comparing with a lengthwise film on the next monitor over. When performed crosswise, the monitor (due to its shape) decreases the image size in order to fit the whole radiograph on the Doctor's screen, making the comparison lengthwise chest x-ray a different magnification. My issue with this is that handy dandy measure tool on the PACS system. If we have the capability to plot measuring points and obtain a detailed measurement, we should still be able to acquire an accurate assessment of how large the heart is with a few extra seconds of mouse-play. If this is the only reason for the lengthwise chest to be performed first, it would seem that radiation protection standards are being compromised in order to save a few extra seconds for the Doc.

So far, this is the only reason I have heard of for performing the lengthwise chest prior to obtaining a crosswise to include the costophrenic angles. If there are more reasons out there, I would love to hear them from you.

Here comes the disclaimer:

I would absolutely NOT recommend (especially for students reading) that you approach your Radiologists with this in an accusatory manner. To simply ask a question is what I am hoping to accomplish here. Managers, Radiation Safety Officers, and the Radiologists should be making these decisions, and tact will go a long way to preserving your Technologist - Radiologist working relationships. I would hope that you could gather information out there, and have discussion in here with the convenience of anonymous comments :-)

Evolve and Elsevier

Now that I have had a chance to see how many students vs. licensed technologists view my blog, I feel like it's pretty evident that I can post a lot of things here that students will appreciate. I also know that those of you who are into technology will appreciate this:

Yesterday at a faculty meeting, a sales representative from Elsevier publishing marketed a service to us called "Evolve." Basically, the service focuses on healthcare related textbooks and offers resources for students and instructors. There are some resources that are free, which I am currently researching for the instructor portion, and there are some that are free for students that you can register online to take possession of.

The thing that caught my eye most was the ability to load your textbooks onto your personal computer or laptop. I hate carrying books, and if your institution allows you to have a laptop in class, then all of your books can be contained in them. The sales rep provided a demonstration for all of us, showing us some of the available tools. The PC version has correlating page numbers synonymous with the hard copy of the book that you receive, and it has all of the same images in digital format that you find in the pages of your textbook as well. You can highlight sections of the textbook with a click-and-drag of the mouse, and there is a "notes" column that automatically saves everything you highlight for reference at any time. I also liked that you can pull up more than one textbook at a time in multiple windows. There are some more advanced features that we did not have a chance to discuss due to time constraints, but overall, this seemed like a handy dandy tool to have.

For instructors reading, there is a way to link the test banks with blackboard (they currently use the angel platform, but the rep stated he would assist in transferring between platforms). There are nice features for online/hybrid courses from resources all the way up to pre-designed powerpoints and lesson plans. Upon registration in the "instructor site" they do a strict screening process including verification of instructor status to ensure that students are not attempting to obtain instructor material.

The cons:

Currently, the publisher is requiring a minimum purchase of three books in order to make this feature available. In addition to the price of the books, there is an additional charge. If you're not interested in an example of the cost/numbers, then please scroll down to the next paragraph. Say you have three textbooks that cost $100 each. All 3 must be purchased and a 20% charge is added, then 10% is taken off the whole thing. So, $300 + 20% = $360...... -10% = $324. Of course, this example is without tax included. The sales rep did say that you could buy one high-priced item (Merrill's for instance), and two low-priced items to still receive the deal.

Once the three (or more) books are ordered, they will custom-create a dvd disc for you that includes the books on your order. You go online to https://evolve.elsevier.com and register as student or instructor to receive your access.

I tried to ask how much memory each book would approximately take, and the rep did not know if the files were compressed on the dvd copy. Also, the digital version is good for updates once you download it onto your computer, but if a new edition of the book comes out (like Bushong in a few months), then you have to purchase the new book (along with 2 other books) in order to receive the digital version from the publisher.

Another con is that you can only download the digital resources twice. Let's say your computer crashes, or your child spills orange juice all over it and it short-circuits, then you've only got one more shot at a download before it will not let you retrieve the product you purchased.

All in all, there are some very heavy pros and for me, some fairly heavy cons, but at least we know that it is available. Until yesterday, I hadn't even heard of this resource. If you can afford it, and if you are a tech-geek like me, then it might be worth looking into. If anything, you can check out the free resources on the website before you make a purchase in order to help you decide yay or nay.

In the News

I just received the ARRT Educator Update for September, 2007 and there are some very interesting topics that relate to us Roentgenographers.

No Cheating!

One of the big changes being made on the application for ARRT certification is a section which asks "has a student ever been subjected to a sanction as a result of violating an academic honor code?" Basically, as of 2008, if a student has ever been caught cheating on an exam, forging a clinical record, or violating the academic honesty policy at his or her institution, it could lead to a hearing by the ARRT Ethics Review Committee. The application itself will consist of questions like, "Have you ever..." With a "yes" answer, you may find yourself before a panel of ARRT folks for additional questions. A similar situation occurs currently if students have a misdemeanor or felony on their record and report it on the ARRT application. As with any review committee, this does NOT mean that you are automatically unable to obtain your ARRT registration, but the process will require additional steps and review by the people administering the exam to decide eligibility. The idea is to uphold the ARRT Rules of Ethics as early as possible.

It is increasingly important that Program Directors inform students who have had a history of such an occurrence, and have been permitted to remain in their programs, that they should be contacting the ARRT with any questions about registration as soon as possible to begin the ethics review process to ensure eligibility. The article states that there is now a pre-application that can be submitted by students who are more than 6 months away from graduating to expedite the process. You can find more info at the ARRT website, and if you can't find the answers online, you may call the Ethics Department at (651) 687-0048 ext. 580.

"I finished my ARRT exam and I probably passed, mom!"

You will find starting on the January, 2008 ARRT exam that you will receive on-site preliminary results for the Radiography and Radiation Therapy exams. Preliminary results have been tested on Sonography and Nuclear Medicine exams for a while now, and have proven to be extremely accurate, and now it's time to give it a try with therapy and gen rad. What an excellent improvement... I remember waiting about 5 weeks for my results. Of course, it is not an official score, and you will not technically be registered until you receive your copy of official results in the mail, but at least you may be able to sleep better at night... you'll probably need that sleep once your program is over!

Looking way into the future

Starting in 2011 (I suppose it's not that far away), the ARRT will be increasing the number of digital radiography questions on the exam pretty dramatically, while decreasing the number of film/screen questions by the same amount. For those of you taking the ARRT exam before 2011, expect to see some pilot questions (that do not affect your score).

Reminder

If any students are looking for scholarship opportunities, don't forget to check out the ARRT Grants and Scholarships page, and look into student membership. There are also scholarships for schooling related to the profession beyond your associate degree in the field of Radiology.

Riddle Me This...

To everyone who voted on my poll posted about the reason you entered the field of Radiography, thank you! You have all made my assignment much easier by allowing me to follow up here.

Anatomy of a Histogram

We've all seen a histogram before if we've used CR or DR imaging systems, but it is important that we all know how to interpret them. Take a look at this histogram:



The horizontal axis in my histogram represents the quantity of information in my image, or the optical density values. In this particular instance, I have densities ranging from a value of 0 (absolute white) on the left to 256 (absolute black) on the right side of my image.

*Note: Keep in mind that this histogram was taken using "Image J" so the bit depth is limited. On a traditional CR system, and depending on the bit depth your system utilizes, you may see up to 16,000 plus shades of gray. This histogram is simply for demonstration.

The vertical axis represents the number of pixels that are assigned within each density value.

In the following image, one of the great aspects of the Image J software is displayed. Depending on where my cursor is placed on the histogram, you can tell on each image what the density value is for each column, as well as how many pixels were assigned that density value. In the image on the left, the value (or degree of density on a scale of 0-256) is 73. The count (or the number of pixels exposed with this density level) is 456. In the image on the right, my cursor was moved over a higher density value of 188, and a higher count of 5883. So in this image, the crosshair placement represents a darker density assigned to a greater number of pixels.



Just as a point of reference, this is the image represented by the histogram:



The CR system has a pre-programmed algorithm for each type of exam you do... this is what you are selecting when you input "chest lateral" before image plate scanning. This tells the computer that a histogram similar to the pre-programmed shape will be scanned. This is where the CR system can produce errors. Depending on the raw data that is scanned, the computer will assign a range on your histogram termed "values of interest" or VOI. Unfortunately, the Image J software did not include this, but I have represented the VOI with red lines in the following image:



The VOI on the histogram helps to determine your Exposure Index (Kodak) or S Number (Fuji), as well as how your image will be rescaled. In first generation CR systems, the operator could slide the VOI to the left or to the right in order to visualize recorded anatomy better, but most current applications do not allow the radiographer to do so. It may be possible, however, to apply a different LUT (lookup table) to the image to make adjustments. So when the computer applies automatic rescaling (the computer's attempt to adjust the image due to over/under exposure) to your image, the process may fail if the original histogram analysis is incorrect. Believe it or not, it is STILL very important to utilize the proper exposure factors.

This brings us to an important role of the software, histogram equalization. Equalization is performed by the computer in attempt to produce a more uniform histogram to increase the level of contrast in your image. After the original histogram is derived, an "inverse" histogram can be calculated and a spreading (or commonly termed flattening) of histogram values can be applied. Compare this image before histogram equalization and after:





This is a very basic explanation of a histogram and how it is utilized in a CR system. It would be easy to go onto many tangents from here (which I have a bad habit of doing in-person). A number of processing and post-processing errors can occur that I hope to dive into in the near future, but a basic understanding of histogram analysis is required. In the meantime, I would like to encourage everyone reading this to familiarize yourselves with the histograms utilized in your own imaging departments, and maniplulate them if you have the capability on your CR system and/or PACS terminals. There's not a lot of information about this in current textbooks, but I can imagine that we will all be responsible for knowing more about these things as we continue to replace conventional automatic processor technology with digital equipment.

Image J

I recently became aware of some free downloadable software that I found incredibly useful both as a student and an educator. Thanks to the Radiography faculty at UNC, I'm in love with Image J!

It's an online PACS toolset that allows you to manipulate any image you can view on your computer in multiple formats. Now, this isn't a database of images, but you can do pretty much anything that a PACS system can to any picture that you already have stored on your computer. Here's what you'll see at their home page:



To download, go to the "download" option at the very top of the page and click... then select the operating system you are utilizing on your PC. I happen to be using Windows at home, but notice one thing before you download - you can download with or without JAVA software included. I know I have JAVA on my computer, so I saved some room and chose the "without JAVA" option. You'll notice the file size is much smaller (1.7 MB compared to 21 MB). If you noticed already, I used Image J to create these images with a screen capture tool.



If you're familiar with PACS systems, you'll have lots of fun bringing up any image (particularly radiographic images) and playing around with the software, but there are many user-friendly features similar to what you might accomplish on photoshop with this software. If you go to the "documentation" hyperlink, there are tutorials available for you.



Once downloaded, you can open an image by going to file, open



Then select a picture from a file on your computer (or download something online first). Disclaimer - you must be aware of copyright infringement laws depending on the use of the picture you are downloading. Make sure to reference where you obtained the picture and/or obtain permission to use it :-)



Once you have selected a picture, you can begin utilizing the software to your heart's delight. This is a quick-start to get you going, but I encourage you to check out the "documentation" link listed above to learn about all of Image J's features. If you are planning on using this software for a school project or a lesson plan, it's worth investing a few minutes. I hope you like it as much as I do!

Lumbar Spine Obliques

Even on a patient with normal anatomy, lumbar spine obliques can be quite a challenge no matter how many years of experience you have. If you've memorized the "scotty dog" anatomy, that's great and it will come into play during the critique of your images, but a basic understanding of how the anatomy is laid out in planes is good to know before you begin your positioning.

On most patients, the cervical spine is in the same plane as the lumbar spine, and this can prove to be a valuable positioning tool if utilized properly. In other words, if a patient is lying on their back and you had do take a tomo slice of the c-spine, the same exact tomo slice, centered over the lumbar spine would work as well. Additionally, if you look at a (normal) spine in the anatomical position, then rotate that spine 90 degrees, you could draw a straight line extending from the cervical spine down to the lumbar spine and it will be in the same plane.



So if you can go from AP to lateral with the C and L-spines in the same plane, then you should be able to go half-way (into an oblique position) and still have them in the same plane.



Of course, it's easy to demonstrate this with elaborate stick-man drawings, but it requires a bit of forethought when doing this on a patient. I like to use a radiolucent pad on the table for a couple of reasons... one, it's just mean not to when you have one available, and two, it is a valuable positioning tool when there is a sheet underneath it. It can easily be slid with a patient on it to better align or even help rotate the patient.

So, with the patient on a pad, position and shoot your AP film. I like to perform the RPO next, so I would inform the patient that I am going to roll them. If it is a small enough patient, it's easy to roll them instead of giving them instructions to roll. When they roll, they usually slide their hips over before rolling one way or the other. You can simply grab your 45 degree sponge and be ready to lift. Grab the pad by the patient's shoulders with one hand and hips with another. Slide them away from the center of the table if necessary so you don't roll them on the floor. Roll them up placing the sponge underneath the pad to the desired position. The sponge shouldn't slip if it's directly on the table.

If your patient is too heavy to do this with, some simple instructions will prevent them from shifting their hips, misaligning your C and L-spines. For RPO, have them bend their left knee. Then have them reach their left arm across their chest. Standing on their right side, place one hand on the left shoulder and the other on their left knee and just assist them while they roll. Wedge your sponge underneath and you're all set.

Once obliqued, align the L-spine and center your tube like you normally do. Now you have another way to check your positioning... go to the head of the table and see whether or not your central ray is in the same plane as your cervical spine. This only works when the patient does not slide their hips. Make minor adjustments as needed and check your results.

For conventional centering, it's always a good review to know the "finger-width" measurements that work for you. Look at an L-spine oblique film on an average sized patient that's centered well (print one out if you need to in order to get "actual size).



On the printed image, check to see how many fingers it takes you to place the horizontal crosshair at the center of L-3's vertebral body. Then see how many finger-widths it takes from the ASIS to the center of L-3. This should be a film that you performed, and it should be positioned exactly the same with each patient. If the patient is not obliqued the same amount, then the distance from the ASIS to L-3 will change. This is the most accurate way to know what works for you. You may have learned this in school, but I would bet that the person teaching you this had different sized fingers than you, and you have to measure this for yourself. The same thing goes with your spot film.

For laterals and spot films, you still need to keep the C and L-spine in the same plane, but the most common errors are in over/under-rotation - not the whole body, but in the shoulders and hips not being in the same plane. But that's another post...

On a Personal Note...

A couple of weeks ago, I sustained a knee injury which was a freak occurrence, random happenstance, and still, a very confusing injury to me. I am well aware of proper body mechanics and posture, and was practicing them to the best of my ability when this occurred (I know this because there were three students in the room - one helping me with the patient's legs - and I made a mental note to demonstrate proper lifting technique).

I was performing a two-man lift moving a patient from wheelchair to stretcher (or gurney as I learned on the left coast), lifted the patient off the chair, placed his hips on the stretcher, and while I was lowering his shoulders onto the stretcher, felt a "pop" in my knee accompanied by instant pain and an inability to bear weight. I thought for sure I had torn a ligament, and thankfully, this occurred after the patient was safely on the gurney.

I had an initial set of x-rays that day that showed lateral joint effusion (my opinion) which the doctor called normal. After protesting and noting a few other discrepancies, I decided to obtain a second opinion at the local Emergency Room the following morning. A second set of x-rays showed no fracture that I could see, or that the Radiologist's report could identify. Still, I was referred to an orthopedic surgeon for a follow-up visit. We did the range-of-motion tests, which were accomplished easily by the time I got in to see her as it was healing nicely I thought. And then she pushed down on the lateral part of my knee right at the joint, and I felt like I was going to pass out it hurt so bad. Needless to say, an MRI was ordered "just in case."

So I had my MRI yesterday, and showed my films to a Radiologist that I work with... it seems I have a tibial plateau fracture, nondisplaced, but rather large that didn't show up on the x-rays at all. He said it was definitely there, but the angle of the fracture made it appear to be a part of the cortex on the tibial plateau. I found myself looking at the x-rays in vain trying to see the original fracture, and I've been walking on it pain-free for about a week now.

What I've learned:

I already knew that some fractures might not be seen on plain films, but now have first-hand credibility to that claim.

Also, no matter how good your body mechanics and posture are, we still perform a job with lots of lifting that wears on your body over time. I wonder how bad my injuries could have been without proper body mechanics?

Finally, document everything - and document well. Seek second opinions if necessary and write as much detail as possible, not only for yourself, but for patients that you encounter when you are performing your daily examinations. You never know how much it will help them.

UNC Digital Radiography for Educators

I am very excited to be attending a conference for educators on digital radiography at the University of North Carolina at the end of this month. My supervisor and a coworker attended the last conference held in June and returned with high praise of the instructors, the information, and overall presentation given at this seminar, and I should have plenty to write about upon my return. I do believe they put this conference on every year, but there is limited room and reservations (for me) had to be made well in advance. For any educators out there teaching general radiography, you might want to check out their ITENERARY AND WEBSITE. It's a 25 unit seminar given over four days and only open to radiography educators.

The anatomy of an ERCP

A few of my students have expressed interest in learning more about the basics of an ERCP so they know what they're looking at while observing one. They are really quite simple for the technologist to perform, but there is a lot going on during them that you need to be aware of (for any other reason than to know what is expected of you during the procedure).

First, you need to know your basic anatomy.



Before you begin any fluoroscopy, the G.I. doctor will have the patient in an LAO position (usually) and under conscious sedation, will feed the endoscope into the mouth, down the esophagus, through the stomach, ultimately to visualize the duodenum. The video monitor that the GI team brings with them will display the region around the c-loop of the duodenum in hopes to visualize the ampilla - where the common bile duct empties into the duodenum.

The purpose of this exam (at least diagnostically) is to obtain an angiogram of the CBD and connecting vessels, or a cholangiogram. As we know, an angiogram cannot be done on specific vasculature without a selective catheter. The whole reason we use the endoscope is so that we don't have to surgically go in and dilate the CBD with a catheter and guidewire. We can do it with minimal invasion of the body as a same-day procedure.

So as you're watching the GI team's video monitor, they will be searching for the ampilla, and attempting to dilate it with a catheter and guidewire. In some cases, it is easy to spot because there will be bile spewing from it. You should look for a curve in the bowel with an elevated mound around the corner - this should be the ampilla.



The picture on the left is the pre-dilated ampilla, and on the right there is a catheter that is already placed in the CBD.

Now comes our part... the endoscope is too large to fit inside the CBD, so we must rely on fluoroscopy to visualize the hepatic vasculature. Once the ampilla is dilated, a guidewire and catheter are usually inserted. Fluoroscopic guidance is needed to assist in proper placement of the guidewire and catheter, and a diagnostic angiogram should be performed. The doctor will inject contrast to see if there are any stones, strictures, or any other abnormalities.





Once a diagnostic angiogram is performed, an interventional portion of the procedure can be performed based on the findings. If there are stones, they can be retrieved with a balloon or a basket, a stent can be placed or removed, or angioplasty can be done (widening of the vessel with a balloon). Keep your eyes open for new treatments on the market utilizing new technologies and selective devices.

Lordotic Much???

One of the most common errors I was guilty of as a student (and as a new technologist) was having a lordotic chest x-ray any time I did an AP view in the stretcher. There is a simple fix to this that I have yet to see in a textbook, but I have heard literally dozens of technologists use this tip: angle perpendicular to the sternum. Here's what your AP chest should look like; with emphasis on curvature of the ribs and the amount that the clavicles dip down into the apices:



And how here's what a portable chest sometimes looks like if you make your central ray perpendicular to the cassette:



I know what you're thinking... "Why is it that in a PA standing chest, this doesn't happen and I'm using a perpendicular beam?" Well, when you perform the PA standing chest, what do you do? You roll the patient's shoulders foreward so that the sternum is up against the bucky, making it parallel to the IR. Think about this... if you were to leave the patient in the same position and simply turn them around to be facing the tube, you would probably be able to make a fist and place it between their shoulders and the bucky. Let's look at this lateral projection for a point of reference:



The red line indicates the central ray passing through the sterno-clavicular joints. This patient's back is almost vertical, as it would be if placing a film behind them for the AP sitting chest, and there is not much lung field above the sterno-clavicular joint. You might have to lean this patient forward for the AP projection to demonstrate the clavicles in the lung field at all. Now if I angle perpendicular to the sternum, it will project the clavicles down into the apices as it would if I were rolling the shoulders forward for a PA projection:



Another common error that produces similar results is patient positioning in the stretcher. Ideally, you need the patient sitting upright with the stretcher at 90 degrees with your cassette behind the patient. What you want to do is have the patient scoot (or you may need to slide them before you sit them up) so that they are bending at the waist with the stretcher. You don't want a gap between their hips and the upright portion of the stretcher. This elevates the clavicles, making a lordotic position similar to the standing lordotic chest we all learned about in school and shown here:



If you combine this error with the previous error of not angling to the sternum, the resulting image could be horrid. Check out the following picture:



The first central ray would produce a lordotic image with a foreshortened lung field due to the angulation of the patient (caused by not having the hips flush against the stretcher). The second central ray would project the clavicles downward into the apices as needed, but would probably produce an elongated effect due to the patient's hips being away from the IR. The lower lung fields have increased OID, causing magnification which may cause the radiographer to be unable to include the entire lung field on the image.

For best results, keep it simple: sit the patient up as much as possible, bending at the waist where the stretcher flexes. Prevent OID on all of your film, and angle perpendicular to the sternum to avoid a lordotic projection (and don't forget to shield).

Quick-Centering for Surgical Fluoroscopy

One of the worst scenarios you may encounter is operating the c-arm for a procedure you have never done before without a more experienced wingman. Once that license comes off the printer with your name on it, training is over and you are expected to perform as a "licensed tech." These are some basic quick-centering tips for c-arm procedures in the O.R. Talk to me Goose!

Pacer insertion – center over sublcavian vein of affected side. In other words, if the doctor is working on the patient's right side, then he's going to be inserting a guidewire into the right subclavian and sending toward the SVC. What you don't want him to do is feed that guidewire in a long way and just hang out with your c-arm centered at the right ventricle. That guidewire can sometimes turn and go up the neck. You are controlling his eyes (the c-arm) for this part of the procedure. As we know, we don't want to push a guidewire into a small vessel because you run a risk of dissection if pushed hard enough. At the very least, it will give the doc something to get upset at you about. Try to find out which lead is being placed first (atrial or ventricular), and once the guidewire is in the SVC, keep the atrium or ventricle in center of field, including as much wire as possible.

Spine – center to the level of surgical procedure. If you are doing a cervical spine, try to include C1 or C2 as a point of reference for the surgeon. It's not that he can't tell what vertebral level he's at, but any confirmation that he is in the correct location with his instruments will be reassuring. He's probably under a bit of stress... If you're doing a lumbar spine, you may want to consider placing T-12 at the top of your field so he can see ribs and count from there. For the T-spine, doing this would be out of your field of view. Depending on the doctor, they might have you count at the beginning of the procedure while he marks the correct location with a sharpie or needle.

Hip – acetabulum should be in the center of the field in the AP projection. It should be in the lateral margin of the field of view for the lateral projection. This would be an excellent procedure to use a manual technique on depending on your patient and the type of procedure being performed. I'll write more on manual techniques in a post in the near future.

Angiogram – center at occluded area. If you've never seen an angiogram or don't think you can spot an occlusion, just look for the pinched area of the vessel. If you're c-arm is equipped with digital subtraction, you could be asked to perform a runoff. This is when you will be following a bolus injection down an extremity (we'll say leg for example. You should try to do a practice run with fluoro before any contrast is injected. You will need to make sure that your c-arm is positioned so that you can simply roll it sideways down the extremity. As you are rolling, it might be a good idea to unlock the lock that allows you to move the image intensifier away from you to allow for slight bends and curves in the vessels. Just remember to try to keep all vessels in the center. You want to visualize them full of contrast, so if they're not dilated and crisp, you might want to slow your c-arm motion down until they are, then procede moving it distally once you have good fill.

ERCP – endoscope should be placed at 6 o’clock in the field of view. If you can remember the anatomy, the common bile duct (CBD) is the most inferior portion of what we would like to image. If we follow that duct superiorly, we will have a branch of the cystic duct (CD) leading to the gallbladder (GB). Once that branches off, it's no longer the CBD, but is not wht common hepatic duct (CHD). This branches into right and left hepatic ducts (RHD, LHD), and then into smaller vasculature that you may never need to name. Sometimes we'll even see the pancreatic duct (PD) cutting transversely away from the GB. When and injection is being made, get as much of the biliary tree as possible without clipping the CBD.

Thanks...

To those of you who are visiting by way of the ASRT Scanner, I thank you for stopping by. I haven't been as active on this blog as I would like to be (or as I have been in the past) due to working 2 jobs, doubling up on classes for myself this semester, and a fairly new child in the home. I hope that you are finding this blog at least thought-provoking, and I encourage you all to participate by leaving commentary on practices that have worked for you. I will tell you right now that I don't claim to have "seen it all" but I know that with the wide range of experience possessed by everyone reading, we could most likely produce quite a collective set of best practices, tips, and tricks of the trade to further expand on our expertise in this profession.

So thanks again, and I look forward to continued discussion of more topics soon.

Angling to the Patient (for skull)

One of the most difficult things about performing any cranial work is those maticulous angles that must be acquired... 15 degrees caudal for the caldwell skull for example. Here's a simple suggestion to help you acquire the appropriate angulation when the patient cannot move:

First, place the patient in the desired position (or as close as they can manage). For the caldwell, the OML must be perpendicular to the image receptor. When the patient cannot do this, align the central ray to the OML by the side crosshair on the collimator housing or the laser light if you have one. If you don't have a light that is visible on the side of the patient's head, you can use your tape measure for a rough estimation. Once the tube is angled to the patient's OML, note the degree of angulation (10 degrees cephalic in this example).



Once you know how many degrees and in which direction the OML lies, you can angle accordingly. We know that a 15 degree caudal angle is applied to the OML if the patient were able to assume to position, so because it is a caudal angle, we subtract 15 degrees from the previously noted angulation of (+)10 degrees. 10 - 15 = -5 degrees, or 5 degrees caudal angulation.



Of course, with any degree of angulation, you may see some shape distortion on your radiographic image, but that is an acceptable sacrifice when you have all of the anatomy appropriately presented on film (or the monitor) for the Radiologist.

Thoughts on C-spine Obliques

I think most people are pretty happy during the student experience if they just get the whole c-spine on the film. You may position everything appropriately according to the x-ray atlas, but your films may not appear textbook depending on your patient's body habitus. Here are a couple of tricks for fine-tuning your c-spine obliques:

On obliques, the main goals are to visualize the intervertebral foramina, as well as the intervertebral joint spaces while including C1 - C7. Let's look at controlling factors for each, as well as a couple of films to refer to.





Intervertebral foramina - these are those round-looking things that you should be able to drive a truck through on the lateral side. You can visualize these if you have the appropriate amount of rotation. 45 degrees may not always work for everyone, depending on minor variances in bone structure, and definitely if there is any sort of lordisis or kyphosis. The first picture displays them beautifully, and the second gets a little bit closed off toward the T-spine. My guess at the error on #2 was that the shoulders were not rotated 45 degrees, while the head was turned completely lateral. This produces a different appearance in the foramina from proximal to distal, and this is probably why the newer versions of the atlas require no lateral rotation of the cranium. You know you're over-rotated if you are closing off the foramina and see spinous processes elongated laterally to them. You are under-rotated if you are closing off the foramina and don't see spinous processes.

Intervertebral joint spaces - this is not controlled by rotation, because you should see these in every view of the C-spine. Tube angulation is the key factor here. The second film above shows much better intervertebral joint spaces than the first. While the first excels in foramina demonstration, it would seem that the angle of the tube is too shallow to see a clear separation between the vertebral bodies. If you ever wondered why positioning atlases say "10-15 degrees, or 15-20 degrees," this is exactly why. No patient has exactly the same bone structure... this allows for the "majority" of patients. Someone with a normal curve on the c-spine might be able to employ a 12 degree angle on the oblique, while a kyhpotic patient may require 25 degrees. The key is in looking at your lateral view. I suggest performing your lateral first.





The patient in the first lateral will definitely need a steeper angle than the second. Difficult to see? Take a pen, or even your hand and do the following: Place the tip of your pen/finger at the dens of film #1. Angle your pen/finger so that the tip remains on the dens and the shaft of the pen runs through the vertebral body of C-7. Now maintain that same angle and slide the tip of your pen/finger to the dens of film #2. You should see a definite difference in position of the vertebral bodies here. Film #2 may require a 10-12 degree angle, and film #1 may take a 15 degree or more.

The slow journey back to normalcy

Good morning everyone,

I just wanted to write a quick note to say that I'm back from my intermission... I moved over the past couple of weeks and have finally settled into my new place after opening escrow, cancelling all of my utilities, having someone back out of escrow, reinstating my utilities, and having the same person back-back into escrow to finally close on our home last Friday. Sound confusing? Tell me about it!

On a good note, I've got only minor details to sort out with the remainder of my "getting settled in" phase of the move, and I will be able to discuss some more radiography topic by the end of the week. I've always got radiography on the brain, and I have lots to say. I'm the guy who can't help himself when a television show or a movie has an x-ray hanging backwards - I have to tell everyone I know how lazy the creators of the show are that they couldn't even figure out how to hang an x-ray properly according to the anatomical position. X-ray basics 101! I must admit, I give scrubs a free pass due to its comedic nature and extreme awesomeness.



Anyways, thanks to those of you who haven't given up on my blog just yet :-)

Odontoid trouble?

One of the most difficult projections for a lot of radiographers continues to be the open-mouth odontoid view. Here are some alternate ways to image the odontoid:

Most technologists can acquire an open-mouth and at least get some of the C2 vertebral body, but commonly clip the dens. In this case, you could do a Fuchs (not to be confused with Scottish profanity) by aligning the CR perpendicular to the MML and centering 1" below the mental point.


You could simply adjust the elevation of the patient's chin or you could angle your tube cephalic/caudal depending on the need. Review the anatomy on the preceding image, remembering that you need to align the tips of the incisors with the base of the skull (or as I like to use, the mastoid tips which are easily palpable from the patient's side). And simply for review (not to insult anyone's intelligence), the labeled image at the beginning of the post could be improved upon by lowering the chin because the incisors are above the occipital bone. You would have to raise the chin if the incisors were below. All of these are common practices, and should probably be attempted before proceding to the next reccommendations.

How would you obtain an odontoid view on someone with a mandibular fracture, or with their jaw wired shut? Well, there are three ways:

1) You could blast right through the mandible. This would be the easiest, increasing your kVp to about 85 should do the trick. You can lower the SID to about 30" and this will minimize the detail of the mandible/teeth superimposing the dens.

The following two options will work if there is a lot of dental work or wiring in the jaw.

2) You could oblique the head and do unilateral views of the lateral masses. For the right side, you should attempt to keep your normal alignment of the incisors and mastoids while rotating the head to the patient's left. Do it just enough so that the mandibular rami (side up) crosses over the patient's midline over the neck, freeing the jaw from superimposition over the dens. Take your film with a perpendicular beam, and you will see the right lateral mass and most of the dens. Be cautious not to over-rotate the patient's head, or you will close the joint space between the dens and lateral mass on the side you're trying to image. You can do the same thing for the opposite side rotating the head in the opposite direction.

*I had trouble finding radiographs for this one, but I'll post one if I have the opportunity to perform this method in the near future.

3) You could perform tomograms. Just like for your IVP, lay the patient supine. With calipers, measure the distance from the table to the EAM, then add one cm. This should create a focal point right through the dens. You may have to take additional slices through the vertebral bodies. I would suggest 1/2 cm incriments posterior to the initial dens image. For example, if your initial measurement from table to EAM was 10 cm, then you add one, your first slice would be at 11 cm. I might try 10 1/2 cm next, then 10 cm and show the radiologist to see if any additional films are required.



And last, and probably least, another method for obtaining the dens can be performed, but not reccommended unless nothing else works. In my experience with radiograpy on patients from some Asian countries (the skull takes a less oblong shape), you may align the incisors and the base of the skull perfectly, but still will not see the dens free of superimposition. You can align the patient like you normally would, but lower the SID as close to the patient's open mouth as possible. This allows for a more dramatized beam divergence, eliminating the incisors and mandible from being able to superimpose the dens. I would not reccommend this be practiced under most circumstances due to radiation protection purposes. The only reason I would use this is if the patient's insurance didn't cover a CT scan, and all other options had failed or were unable to be performed.

Hopefully, we can become better as we practice more of these and have the ability to assess which methods would probably work best on the initial exposure. I hope this adds to your bag-of-tricks!

Intermission

I just wanted to let those of you who read this blog know that I have not disappeared... rather, I am taking a small break from blogging to manage a few personal things going on right now. I have lots of good material in mind for the blog that I will be working on soon. Thank you for your patience.

Dual C-arm Setup

If you've ever worked with a surgeon who has required 2 c-arms during a procedure, it can be quite intimidating the first time you are asked to set one up. Here's a simple method for doing so... and depending on the procedure, remember you can alter positions of each c-arm to achieve the same result.

Bring your first c-arm in like you were doing a simple AP:





Angle the c-arm 30-34 degrees and lock it in place. Then orbit the c-arm into a lateral projection.



Drive c-arm #2 into place from the head of the table. I would suggest extending the arm as far out as it will go when aligning so that if the surgeon needs it moved to work, all you have to do is retract the arm while leaving the base locked. If you collide with the arm of the first c-arm, feel free to angle it more to provide a clearance.



After the initial setup is complete, make sure to orientate both images to appear how the surgeon wants them on the monitors.

*Note: try to avoid fluoro on both c-arms at the same time during the procedure unless the surgeon actually needs it. The image intensifiers will receive scatter from either c-arm if both operate simultaneously, degrading the quality of your images. You should be able to off-set the timing by a split second if the surgeon requires a single shot of each.

You are now ready to provide the surgeon with AP and lateral projections without any c-arm manipulation!

Fat Pad Sign

Occasionally, a pediatric patient, or even the rare adult patient will have pain from a fall or traumatic injury, and there is no visible evidence of a fracture to the technologist or the radiologist. There is a tell tale sign that there is in fact a fracture without ever seeing the fracture itself... the fat pad sign.

It is usually seen on children, but can sometimes be seen on adults. The patient has decreased ROM or extreme pain when being positioned for their radiographs. The films show joint effusion marked by increased optical density surrounding the bone or joint. The provided film displays this increased radiographic density on the anterior and posterior borders of the humerus in the lateral projection.

Most radiologists (from my personal experience only) are comfortable calling a fracture when a fat pad sign exists. If I could paraphrase the reason for this as stated by a radiologist I used to work with: The other possible causes of this type of effusion can only occur with a ligament or tendon tear around a joint. If it is not directly involving the joint, it is reasonable to conclude that a fracture is what caused the effusion. It is not an injury that will require surgery, and whether the injury is actually a ligament/tendon tear or a fracture, the treatment will be the same; splint or soft cast and no surgery. A potentially incorrect diagnosis of "normal" would minimize the amount of time for immobilization and could potentially risk further injury if not allowed to heal fully.

Pediatric Chest X-ray

The most basic exam can prove to be the most difficult of challenges in your day if you've ever had an uncooperative child. Depending on the age of your patient, different approaches can be made.

Before the patient and/or parent arrives in the room, you should have all equipment set up in advance. Make sure to have an extra lead apron for a parent if they wish to remain in the room with the child. I always like to encourage this except when the physical presence of the parent seems to make the child more combative.

You should always attempt the exam without immobilization first. This doesn't mean you need to make a bad exposure. Use your judgement about the quality of your radiograph before you commit to the attempt. Better to try unsuccessfully without a radiation dose than to settle on a sub-par quality film and end up repeating anyways. Be sure to communicate with the parent about immobilization techniques and requirements of the procedure. This may encourage better parent participation because they just want to get it over with to minimize any emotionally traumatic experience the child may have to endure (i.e. the pigg-o-stat). Don't forget to ask the mother if there's a possibility she could be pregnant before letting her assist.

The table-top attempt:

Place an 8x10 or 10x12 cassette in a grid holder at one end of the table. At the other end, align the x-ray tube horizontally to the cassette. Consider placing a sheet over the cassette so the patient will not be startled because of its ice-cold tempurature. Have mom or dad put the lead on and have a small lead apron for the patient (a thyriod shield will work on small patients). You should already have a preliminary technique set up for the AP chest. Place the patient's back against the cassette and the shield over their lap. Mom or dad can hold the arms to the side, grasping mid-humerus, and making sure to keep the child's back flat against the cassette.



For the lateral, simply rotate the patient's legs to their left 90 degrees. Have a parent stand in front of the patient and grasp the arms at the elbows bringing them together to touch in front of the face, also ensuring proper elevation above the thorax. I typically like to increase the kV by 10% and double my mAs from the AP to the lateral, but everyone has a different rule of thumb.

At three years old, the pediatric patient may be too large for the pig-o-stat. If they are somewhat cooperative, you may be able to provide a foot-stool and stand them at the upright bucky. Most will not be able to perform a PA projection because they are trying to see all of the equipment and may be a little frightened to turn their back. I worked at a facility where we put a rather large "Shrek" sticker on the bottom of the x-ray tube to give them something familiar to look at for the AP projection. Another sticker was placed on the wall directly in front of them when they were in the left lateral position. All we said was "look at Shrek" and they cooperated, but you better be on the rotor because it didn't last more than a few seconds.



The pigg-o-stat:

If you have an absolutely uncooperative patient that requires immobilization, the pigg-o-stat is the method of choice for radiographers. Most come with different sized adjustable flanks and you may want to sneak a peak at your patient before bringing them into the room to estimate the appropriate size.

If you've never used one or seen one, they look like some sort of dark-age torture device, which they could easily turn into if you let the patient sit in them too long. You simply place them into the seat with arms above their head and close the flanks. Make sure to lock them in place. If you have all of this set up in advance, the patient should be in and out in just a few seconds.

Subscribe to our mailing list

What's new in Diagnostic Radiography

If you're like me, you might have learned the practice of radiography on plain film with chemical processors and that oh-so-familiar darkroom smell. Manual techniques actually used to appear differently when you doubled your mAs or altered your kVp to adjust scale of contrast. You may currently miss the ability to create a soft-tissue technique for an extremity without post-processing manipulation or to use extremity film at 50 kVp and obtain the best recorded detail imaginable. You may feel that the skill that you were once good at has become obsolete. Well, let's face it, a lot of that knowledge gained only from experience is becoming unneeded.

I remember my earlier days of radiography in the late 1990's when our facility received the first CR system in the local area. All of the hospital administrators from competing hospitals toured our facility in amazement when they saw how you could manipulate the image in PACS. I remember the technical conversion from our regular 400 speed film to CR... we were told to begin by trippling our mAs on every exposure. Of course, this seemed like an outstanding increase in radiation to the patient, but we were told that it made up for the amount of repeats required on conventional film due to improper technical factor formation. All you had to do was perform post-process manipulation and you could turn it in. We were the test site... there was no S number or exposure index. We were to create technique charts and give them to the engineers from the company that provided us the equipment.

Well, some time has gone by, and the amount of radiation required for a CR image has gone down quite a bit. We have more accurate ways of optimizing our exposure factors and we're more strict with quality control. But DR equipment has been making some incredible changes lately. Sure, DR technology has been around for some time, but for many facilities, it has not yet been cost-effective to switch the whole department over to DR. The advantage of CR is the hospital may utilize old x-ray equipment (tables and tubes) without paying for a room overhaul. Most administrators are probably holding out for the benefits of the new technology are great enough... or until the competing hospitals make the switch.

In the former scenario, I don't think it will be long before those benefits will be top priority. Some of the new software applications that are being utilized are amazingly successful at performing tasks previously unseen on CR or plain film. Take for instance a typical lateral c-spine projection: You only see C-6 on your film and you have to shoot a swimmer's. As displayed on GE healthcare's website, there is a new feature called "tissue equalization" that provides the same radiographic density throughout the entire image regardless of differences in anatomical thickness.



There is also another feature called "dual energy subtraction" which allows different anatomy to be better visualized all with the same exposure. As GE states, "Dual energy imaging is a subtraction technique based on the different attenuation characteristics of soft tissue and bone. The two images during the PA chest exam use different energy spectra. Information from the low-energy image (60-80kVp) is combined with information from the high-energy image (110-150kVp; the same image as a standard PA exam) to generate bone and soft-tissue images. The dual energy algorithm has been optimized for thorough removal of bone from the soft-tissue image, while minimizing image noise."







Expect to see more integration of different modalities into the general diagnostic realm in the near future as well. The "Arcadis Orbic 3D" from Siemens Medical is a newer c-arm that can perform 3D images, or basic axial CT slices on extremities in the OR.



Here is an image from their website:



You can view an entire study here (it may take about 30 seconds to load with a cable connection).

In a way, I'm saddened by the inevitable loss of a skillset learned in plain-film imaging. I will miss being able to take a really nice sternum image at 55 kVp or some ribs at 60 kVp and see a noticable difference. However, one of the exciting aspects about this field is the constant lunge of technology into the previously unheard of. It is a great time in our field and we are on the brink of new imaging capabilities every year. We have to keep changing with the technology, and continue to strive for imaging excellence.