The CARE bill (Consistency, Accuracy, Responsibility and Excellence in Medical Imaging and Radiation Therapy Act) is advancing in Congress... an article released October 14, 2009 states that "all medical imaging professionals to be state-certified under standards set by the secretary of the Department of Health and Human Services."
If you live in a State that does not currently require x-ray licensure to take radiographs, this may change soon. According to the article, the bill, if passed, would take effect in January, 2013, and would require any technologist performing x-ray, fluoroscopy, and ultrasound procedures to be licensed under state-specific guidelines.
There are those who oppose this change for whatever reason, but I think this is a good step in the ever-expanding quest to promote professionalism in our field. Considering situations like my last post I believe this has come at a crucial time. There will be opposition to this, of course. Many people have been trained "on the job" in chiropractor's offices, medical assistant positions, and in private doctors offices throughout states that do not currently require this formal training. Physicians who employ these individuals may have to pay more money to hire qualified professionals to take their places, at higher cost to them.
You can view the bill here... or log onto www.asrt.org to get updates on the latest news.
Friday, November 13, 2009
Friday, September 18, 2009
Update on CT Overexposure Court Case
If you were previously unaware of this case, there are additional articles linked at the bottom of this one, found on the "Aunt Minnie" website.
This is one reason why the level of professionalism and proper training for entering this field should be held in the highest of standards, not only in school, but throughout our careers after.
I remember training on a similar model when I did CT, and it took about 8 seconds to perform one axial slice, then an additional 8 seconds to reset itself to the original tube travel position. It was a DOS-based computer with very limited capabilities compared to what is out today. There was no audio recording telling the patient to hold their breath or when they could breathe. We had a microphone and had to count to eight every slice before verbally instructing the patient for each breath hold. An abdomen/pelvis scan would often take more than an hour because the tube would overheat on most patients once we got down to the pelvic bone, and each slice would take an exponentially longer wait-time before the heat unit overload would allow us to safely take the next slice. This was outdated equipment eight years ago when I used it, and I'm surprised to hear that it was still in use. Regardless, the technologist has the responsibility to maintain the guidelines of ALARA.
This is one reason why the level of professionalism and proper training for entering this field should be held in the highest of standards, not only in school, but throughout our careers after.
I remember training on a similar model when I did CT, and it took about 8 seconds to perform one axial slice, then an additional 8 seconds to reset itself to the original tube travel position. It was a DOS-based computer with very limited capabilities compared to what is out today. There was no audio recording telling the patient to hold their breath or when they could breathe. We had a microphone and had to count to eight every slice before verbally instructing the patient for each breath hold. An abdomen/pelvis scan would often take more than an hour because the tube would overheat on most patients once we got down to the pelvic bone, and each slice would take an exponentially longer wait-time before the heat unit overload would allow us to safely take the next slice. This was outdated equipment eight years ago when I used it, and I'm surprised to hear that it was still in use. Regardless, the technologist has the responsibility to maintain the guidelines of ALARA.
Saturday, July 11, 2009
Experaments with Scatter
We know that CR image plates are more responsive to scatter and background radiation than film/screen systems... so we decided to see exactly how sensitive they would be to an exposure within the x-ray room.
A phantom was set up on the tabletop to expose a lateral lumbar spine. We used 75 kVp, 200 mAs at a 40" SID. We did not actually expose an image plate for the lumbar spine, but we wanted to mainly focus on the scatter produced by that exposure.
So we measured 8 feet from the spine phantom and set up a 10x12 cassette vertically with a cassette holder. A hand phanotm was placed in front of the cassette and the exposure was made. The following image resulted on Kodak CR with an exposure index of 1190.
You can see that the scatter was enough to penetrate soft tissue and bone enough to see medulary canal.
We decided to re-create the experiment with the same spine phantom, but this time we placed a chest phantom upright next to a 14x17 cassette, approximately 6 feet away from the spine phantom at about the same height. We ended up with an exposure index of 980.
It was definitely enough to penetrate the lung fields, but may not have been enough to penetrate the shoulder or neck region. 6 feet is the minimum safe distance we should be on all portables... hopefully, this will make us think twice about wearing a lead apron when we shoot portables (especially on anatomy that requires a lot of technique).
As a side note, the chest image really allows us to visualize penumbra... or geometric unsharpness produced at the periphery of the anatomy. We know that the smaller the focal spot, the less the penumbra. We have essentially created a gigantic focal spot because the source of most of the radiation hitting the chest phantom was scattered from different points within the lumbar spine phantom on the table... approximately a 27cm focal spot size!
A phantom was set up on the tabletop to expose a lateral lumbar spine. We used 75 kVp, 200 mAs at a 40" SID. We did not actually expose an image plate for the lumbar spine, but we wanted to mainly focus on the scatter produced by that exposure.
So we measured 8 feet from the spine phantom and set up a 10x12 cassette vertically with a cassette holder. A hand phanotm was placed in front of the cassette and the exposure was made. The following image resulted on Kodak CR with an exposure index of 1190.
You can see that the scatter was enough to penetrate soft tissue and bone enough to see medulary canal.
We decided to re-create the experiment with the same spine phantom, but this time we placed a chest phantom upright next to a 14x17 cassette, approximately 6 feet away from the spine phantom at about the same height. We ended up with an exposure index of 980.
It was definitely enough to penetrate the lung fields, but may not have been enough to penetrate the shoulder or neck region. 6 feet is the minimum safe distance we should be on all portables... hopefully, this will make us think twice about wearing a lead apron when we shoot portables (especially on anatomy that requires a lot of technique).
As a side note, the chest image really allows us to visualize penumbra... or geometric unsharpness produced at the periphery of the anatomy. We know that the smaller the focal spot, the less the penumbra. We have essentially created a gigantic focal spot because the source of most of the radiation hitting the chest phantom was scattered from different points within the lumbar spine phantom on the table... approximately a 27cm focal spot size!
Wednesday, July 08, 2009
Semi-Auto Lab Experament
This week in our imaging lab, we decided to look into the EDR functions even further by performing some experaments on our phantom using the Semi-Auto option, which selects region 5 on the FUJI CR image plate. Our control image, shown first, came out exactly like you would expect it to having the tube, part and bucky aligned, and it was processed on the default "auto" setting (all images in this experament utilized a technique of 70 kVp 3 mAs and 40" SID in the table bucky):
Image #2 kept all of the same alignment, technical factors, and positioning, but we processed it on "semi-auto" to see if the image would come out better... in my opinion on this phantom, I didn't necessarily like it as much. The bony detail through the petrous ridges is lacking and it has somewhat of a longer scale of contrast - undesired if performing this view for sinuses. Note the slight change, yet acceptable S# differences between these first two exposures.
For exposure 3, we decided to keep the semi-auto setting, but we took the x-ray tube off of transverse detent so that everything was aligned except the tube. This is how the field light appeared over the phantom with the cassette alignment underneath:
As you can see with the resulting image, the S# is 3820, which is severely underexposed. The computer is attempting to adjust the density over region 5 on the image plate. Over half of region 5 lies outside the exposure field, which makes the computer think "there aren't many photons here, so it must be underexposed... I'll try to darken the image to compensate because I'm a super-smart computer." We know coputers aren't that smart, and the result is a very dark image over the small bit of anatomy we can see due to automatic rescaling, and it retains its very high S#.
For our 4th image, we kept it on semi-auto, but we started fresh with everything aligned... we then moved the phantom out of alignment. The tube and bucky were aligned but the skull was off-centered like so:
In this image, the S# is 50, which overexposed. The computer is attempting to adjust the density over region 5 on the image plate. Most of region 5 is exposed with the full technique appled without any absorption by the tissue of the phantom, which makes the computer think "there are too many photons here, so it must be overexposed... I'll try to lighten up the image to compensate because I'm a super-smart computer." Again, not smart, just playing by a set of rules and the result is a very light image over the small bit of anatomy we can see due to automatic rescaling, and it retains its very low S#.
We thought these errors were so interesting that we decided to try the alignment mishaps on the "auto" setting to see if it would be more forgiving, or if we would yield similar results. Image 5 was taken with the same misalignment of the x-ray tube that occurred in image 3, but on "auto." Below we see the S# slightly higher than the optimal range at 308, but certainly looking better than exposure 3.
And finally, we reproduced the off-centered patient as in exposure 4 on "auto" and produced a low S# of 50, but also looking better on the auto setting than on the semi-auto where field 5 was the main point of interest.
The lesson learned is that we must out-smart our computer software... be extremely careful with positioning and alignment when selecting any EDR option that will only form a histogram based on a selected region.
Image #2 kept all of the same alignment, technical factors, and positioning, but we processed it on "semi-auto" to see if the image would come out better... in my opinion on this phantom, I didn't necessarily like it as much. The bony detail through the petrous ridges is lacking and it has somewhat of a longer scale of contrast - undesired if performing this view for sinuses. Note the slight change, yet acceptable S# differences between these first two exposures.
For exposure 3, we decided to keep the semi-auto setting, but we took the x-ray tube off of transverse detent so that everything was aligned except the tube. This is how the field light appeared over the phantom with the cassette alignment underneath:
As you can see with the resulting image, the S# is 3820, which is severely underexposed. The computer is attempting to adjust the density over region 5 on the image plate. Over half of region 5 lies outside the exposure field, which makes the computer think "there aren't many photons here, so it must be underexposed... I'll try to darken the image to compensate because I'm a super-smart computer." We know coputers aren't that smart, and the result is a very dark image over the small bit of anatomy we can see due to automatic rescaling, and it retains its very high S#.
For our 4th image, we kept it on semi-auto, but we started fresh with everything aligned... we then moved the phantom out of alignment. The tube and bucky were aligned but the skull was off-centered like so:
In this image, the S# is 50, which overexposed. The computer is attempting to adjust the density over region 5 on the image plate. Most of region 5 is exposed with the full technique appled without any absorption by the tissue of the phantom, which makes the computer think "there are too many photons here, so it must be overexposed... I'll try to lighten up the image to compensate because I'm a super-smart computer." Again, not smart, just playing by a set of rules and the result is a very light image over the small bit of anatomy we can see due to automatic rescaling, and it retains its very low S#.
We thought these errors were so interesting that we decided to try the alignment mishaps on the "auto" setting to see if it would be more forgiving, or if we would yield similar results. Image 5 was taken with the same misalignment of the x-ray tube that occurred in image 3, but on "auto." Below we see the S# slightly higher than the optimal range at 308, but certainly looking better than exposure 3.
And finally, we reproduced the off-centered patient as in exposure 4 on "auto" and produced a low S# of 50, but also looking better on the auto setting than on the semi-auto where field 5 was the main point of interest.
The lesson learned is that we must out-smart our computer software... be extremely careful with positioning and alignment when selecting any EDR option that will only form a histogram based on a selected region.
Tuesday, June 30, 2009
CR Image Plate
With all of the new curriculum material being added to the Registry in the coming years, it is required for us to have good working knowledge of how the photostimulable phosphor plates work with CR cassettes. Most curriculums are encorporating this into study now, and I won't bother going into those details, but I would like to post about an observation I made when reading up on the topic and preparing for some lab sessions with my current students.
According to the Carlton and Addler textbook that our students are required to purchase, the active layer is the photostimulable phosphor layer, which is responsible for retaining a latent image after x-ray exposure. This happens when x-rays ionize the plate, releasing electrons to be collected by an "electron trap" in the conductive layer of the phosphor screen.
This image, taken from the FUJI website (an excellent source for information by the way), depicts the electrons collected in the trap, and representing a stored charge that is now our latent image.
During development of the cassette, a helium-neon laser (a really intense light source), sweeps the cassette during the forward motion of plate travel through the reader, and that charge is released in the form of light photons (following picture also from FUJI).
As you can see, there is a "light guide" which collects the visible light emitted from the plate and transfers it to a photomultiplier tube, which amplifies the light signal. Later it goes to an analog to digital converter to be interpreted into an electrical signal that the monitor can display as our radiograph at our QC station, and so on and so forth.
If you have ever opened one of the CR cassettes, even after a radiographic exposure has been made on it, you might notice that the room light does not fog the image plate. So knowing that an intense light (helium-neon laser) is used to release the charge on the plate during image processing, I wondered if I could reproduce that effect outside of the image processor myself.
Here's what I decided to do... I received two laser pens for my birthday recently (green in luminance) that my wife and I jokingly use to point out things when we watch TV, i.e., physical flaws possessed by contestants on the television show "The Bachelorette," crooked nostrils, stains on clothing, you get the picture (way beside the point, but fun).
I wondered if the laser pens were intense enough to cause a change in the radiographic density on the image plate.
First, I took an unexposed plate and removed it from the cassette and turned out the room lights. I thought "it's photostimulable, so what would happen if I simply shine my laser light on it? Would it emit a visible light? Would it produce a density on my developed image?" Uh... no. After trying this in an unexposed image plate, there was no visible light produced except what was caused by my own laser pen, and no visible density was recorded on the developed image after processing.
So next, I tried a relatively small exposure (about a finger technique) on a cassette, then tried removing the image plate from the cassette to see if I could observe visible light when shining my pen on it. I was not able to perceive visible light when I tried this... why? Probably because the light would be very dim, and the brightness of my laser pen interfered with any that I might have been able to see. There is, after all, a photomultiplier tube which enhances the light emitted by the screen inside the reader. However, when I developed the image, this was the result:
It appears as if my laser light, in fact did have enough intensity to release the trapped electrons from their place in the conductive band. We have an area of decreased density on the image where the my laser pen interacted with the plate and released the electrons. The reader was not able to detect any light emitted from these regions with the helium-neon laser because the electrons had already been released, and no density was provided in that area.
Does this help us in our formation of the image? Probably not, but it does help to understand the process of turning our latent image into the manifest image using CR. I highly reccommend purchasing a laser-pen, even if you never use it for radiography-related purposes, it's still good fun for television. A special shout to my wife - thanks for my laser-pens!
According to the Carlton and Addler textbook that our students are required to purchase, the active layer is the photostimulable phosphor layer, which is responsible for retaining a latent image after x-ray exposure. This happens when x-rays ionize the plate, releasing electrons to be collected by an "electron trap" in the conductive layer of the phosphor screen.
This image, taken from the FUJI website (an excellent source for information by the way), depicts the electrons collected in the trap, and representing a stored charge that is now our latent image.
During development of the cassette, a helium-neon laser (a really intense light source), sweeps the cassette during the forward motion of plate travel through the reader, and that charge is released in the form of light photons (following picture also from FUJI).
As you can see, there is a "light guide" which collects the visible light emitted from the plate and transfers it to a photomultiplier tube, which amplifies the light signal. Later it goes to an analog to digital converter to be interpreted into an electrical signal that the monitor can display as our radiograph at our QC station, and so on and so forth.
If you have ever opened one of the CR cassettes, even after a radiographic exposure has been made on it, you might notice that the room light does not fog the image plate. So knowing that an intense light (helium-neon laser) is used to release the charge on the plate during image processing, I wondered if I could reproduce that effect outside of the image processor myself.
Here's what I decided to do... I received two laser pens for my birthday recently (green in luminance) that my wife and I jokingly use to point out things when we watch TV, i.e., physical flaws possessed by contestants on the television show "The Bachelorette," crooked nostrils, stains on clothing, you get the picture (way beside the point, but fun).
I wondered if the laser pens were intense enough to cause a change in the radiographic density on the image plate.
First, I took an unexposed plate and removed it from the cassette and turned out the room lights. I thought "it's photostimulable, so what would happen if I simply shine my laser light on it? Would it emit a visible light? Would it produce a density on my developed image?" Uh... no. After trying this in an unexposed image plate, there was no visible light produced except what was caused by my own laser pen, and no visible density was recorded on the developed image after processing.
So next, I tried a relatively small exposure (about a finger technique) on a cassette, then tried removing the image plate from the cassette to see if I could observe visible light when shining my pen on it. I was not able to perceive visible light when I tried this... why? Probably because the light would be very dim, and the brightness of my laser pen interfered with any that I might have been able to see. There is, after all, a photomultiplier tube which enhances the light emitted by the screen inside the reader. However, when I developed the image, this was the result:
It appears as if my laser light, in fact did have enough intensity to release the trapped electrons from their place in the conductive band. We have an area of decreased density on the image where the my laser pen interacted with the plate and released the electrons. The reader was not able to detect any light emitted from these regions with the helium-neon laser because the electrons had already been released, and no density was provided in that area.
Does this help us in our formation of the image? Probably not, but it does help to understand the process of turning our latent image into the manifest image using CR. I highly reccommend purchasing a laser-pen, even if you never use it for radiography-related purposes, it's still good fun for television. A special shout to my wife - thanks for my laser-pens!
Wednesday, June 10, 2009
Semi-X
Semi-X is one of the EDR options that can be selected on FUJI CR prior to image processing. You can select this after you have prescribed a specific projection/view, but prior to scanning the barcode for the cassette ID. In this example, I attempted an axillary view of the shoulder on our phantom in the lab:
When selecting the Semi-X option, you will be given a choice of cells (1-9) as seen on the prior post, but it is crucial to properly orient your cassette, and remember how your numbered regions correspond to the green orientation bar.
For my phantom images, I decided to perform a left axillary shoulder, so I placed my green orientation bar (on a crosswise 10 x 12 cassette) closest to the "patient's" neck. This changes the layout of my numbered regions as shown:
I decided to expose my first image without the use of the Semi-X option... the following image was taken on the default "Auto" setting, which forms a histogram based on either the entire image plate, or whatever pixels lie within the recognized collimated field. It is important to note that sometimes on actual patients, the greater the soft tissue density around the patient's shoulder, the more scatter will be produced... especially in comparison with my images from a phantom. The scatter could lead to software being unable to recognize the collimated borders, thus the inclusion of more data in your histogram than what was actually in the collimated field.
This image was shot at 60 kVp, 4.2 mAs, and the resulting S# was 280 on the Auto setting:
My second image utilized identical exposure factors, but I selected the Semi-X option and chose field #7, which should be aligned with the humeral head. This gave me a much more desirable image with an S# of 159, and much better contrast with less density than on the Auto setting:
My third image utilized identical exposure factors again, but I selected the Semi-X option and chose field #4, which should be aligned with the surgical neck and proximal humerus. This gave me an even better image with an S# of 132, and even more contrast with less slightly less density than image 2:
And just for kicks, I decided to perform one more image with the same exposure factors and simulated a common error - improper selection of the numbered region. This error would occur with either improper cassette orientation, or if there was any confusion of where the green orientation bar was located. The following was set to field 6, which is outside the original collimated border, with an S# of 2968. As you can tell, the software is attempting to equalize the histogram for that region on the cassette, allowing us to see the mottle pattern of the scatter, but preventing us from visualizing the anatomy itself... it's telling us that we're severely underexposed - and that would be true if we are trying to visualize something over #6.
All in all, this is a valuable tool to utilize with exams like axillary shoulder, cross-table hip, perhaps trauma and OR views and anything which would prevent you from placing the anatomy of interest in the center of the cassette. Just remember to always know where your green orientation bar is, and how the numbered regions lie in relationship to it.
When selecting the Semi-X option, you will be given a choice of cells (1-9) as seen on the prior post, but it is crucial to properly orient your cassette, and remember how your numbered regions correspond to the green orientation bar.
For my phantom images, I decided to perform a left axillary shoulder, so I placed my green orientation bar (on a crosswise 10 x 12 cassette) closest to the "patient's" neck. This changes the layout of my numbered regions as shown:
I decided to expose my first image without the use of the Semi-X option... the following image was taken on the default "Auto" setting, which forms a histogram based on either the entire image plate, or whatever pixels lie within the recognized collimated field. It is important to note that sometimes on actual patients, the greater the soft tissue density around the patient's shoulder, the more scatter will be produced... especially in comparison with my images from a phantom. The scatter could lead to software being unable to recognize the collimated borders, thus the inclusion of more data in your histogram than what was actually in the collimated field.
This image was shot at 60 kVp, 4.2 mAs, and the resulting S# was 280 on the Auto setting:
My second image utilized identical exposure factors, but I selected the Semi-X option and chose field #7, which should be aligned with the humeral head. This gave me a much more desirable image with an S# of 159, and much better contrast with less density than on the Auto setting:
My third image utilized identical exposure factors again, but I selected the Semi-X option and chose field #4, which should be aligned with the surgical neck and proximal humerus. This gave me an even better image with an S# of 132, and even more contrast with less slightly less density than image 2:
And just for kicks, I decided to perform one more image with the same exposure factors and simulated a common error - improper selection of the numbered region. This error would occur with either improper cassette orientation, or if there was any confusion of where the green orientation bar was located. The following was set to field 6, which is outside the original collimated border, with an S# of 2968. As you can tell, the software is attempting to equalize the histogram for that region on the cassette, allowing us to see the mottle pattern of the scatter, but preventing us from visualizing the anatomy itself... it's telling us that we're severely underexposed - and that would be true if we are trying to visualize something over #6.
All in all, this is a valuable tool to utilize with exams like axillary shoulder, cross-table hip, perhaps trauma and OR views and anything which would prevent you from placing the anatomy of interest in the center of the cassette. Just remember to always know where your green orientation bar is, and how the numbered regions lie in relationship to it.
Sunday, June 07, 2009
Exposure Data Recognition
If you've ever wondered what the "EDR" button on your FUJI CR system is for, it stands for "Exposure Data Recognition." In order to properly utilize this unique feature, we need to know how it works.
FUJI CR plates have 9 sections on them divided equally. If you've ever noticed the green horizontal orientation bar, that should be either placed at the head of your patient (for lengthwise exposures) or at the patient's right (for crosswise exposures). This is important to remember when using the EDR feature.
When using the EDR option, it can only be applied before image processing, and additionally, needs to be selected prior to scanning your cassette bar code associating it with the desired view. The EDR has four modes:
AUTOMATIC
SEMI-AUTO
SEMI-X
FIXED
Automatic - this is the default setting on most IIP's. This mode will sample the entire cassette if it is exposed in its entirety. It also, however, should detect collimated fields and if collimated properly, will only include the exposed areas inside that field as part of the "values of interest" in the histogram (see "Anatomy of a Histogram").
Semi-Auto - this mode will only take a sample from the central partition of the cassette (#5 in the above diagram). As you can suspect, positioning is key when selecting this option, but should be familiar to you if you are comfortable with utilizing the center cell with AEC.
Semi-X - allows you to select one of the nine partitions of the IP. Depending on the anatomical part or projection you are attempting to perform, selection of the proper partition is crucial, as is the need for proper cassette orientation.
Fixed - for those of us who were once comfortable utilizing film/screen combination radiography, this may just be an equally comfortable option to choose. Instead of a histogram and software equalization, whatever technical factors you select will be represented by the density and contrast on your image. A double in mAs will actually be a double in density, and you have the option of choosing a speed class (which is representative of the film/screen speed combo with conventional radiography).
This can be a lot to swallow or to know how to use appropriately... more specific posts for each option to come!
FUJI CR plates have 9 sections on them divided equally. If you've ever noticed the green horizontal orientation bar, that should be either placed at the head of your patient (for lengthwise exposures) or at the patient's right (for crosswise exposures). This is important to remember when using the EDR feature.
When using the EDR option, it can only be applied before image processing, and additionally, needs to be selected prior to scanning your cassette bar code associating it with the desired view. The EDR has four modes:
AUTOMATIC
SEMI-AUTO
SEMI-X
FIXED
Automatic - this is the default setting on most IIP's. This mode will sample the entire cassette if it is exposed in its entirety. It also, however, should detect collimated fields and if collimated properly, will only include the exposed areas inside that field as part of the "values of interest" in the histogram (see "Anatomy of a Histogram").
Semi-Auto - this mode will only take a sample from the central partition of the cassette (#5 in the above diagram). As you can suspect, positioning is key when selecting this option, but should be familiar to you if you are comfortable with utilizing the center cell with AEC.
Semi-X - allows you to select one of the nine partitions of the IP. Depending on the anatomical part or projection you are attempting to perform, selection of the proper partition is crucial, as is the need for proper cassette orientation.
Fixed - for those of us who were once comfortable utilizing film/screen combination radiography, this may just be an equally comfortable option to choose. Instead of a histogram and software equalization, whatever technical factors you select will be represented by the density and contrast on your image. A double in mAs will actually be a double in density, and you have the option of choosing a speed class (which is representative of the film/screen speed combo with conventional radiography).
This can be a lot to swallow or to know how to use appropriately... more specific posts for each option to come!
Thursday, February 05, 2009
Hiatus
I want to apologize to everyone following my blog... it has been quite a while since I've had the opportunity to post anything, but I'm planning on diving in full-force again within the next couple of months. Still have a lot of visitors, and I've had many requests for postings on some rather good questions, so I'll have plenty of material! Thanks for following along after the long silence!
Thursday, October 16, 2008
15 Free CEU's!
I recently received word thru a yahoo group that there are 15 FREE CEU's available from the newly formed Online Digital Imaging Academy.
These CEU's are organized into 11 different modules, and take an estimated time of 15 hours to complete. If you are already a Registered member of the ARRT, they are free to you, and if you are a member of the ASRT, your CEU's will be automatically tracked for you.
This should be great for the technologist who has never had any formal instruction in the digital imaging media, and promotes safe and effective usage of the latest technology in the imaging world.
You can sign up, and find more information HERE.
Special thanks to Nancy for letting me know this was available.
These CEU's are organized into 11 different modules, and take an estimated time of 15 hours to complete. If you are already a Registered member of the ARRT, they are free to you, and if you are a member of the ASRT, your CEU's will be automatically tracked for you.
This should be great for the technologist who has never had any formal instruction in the digital imaging media, and promotes safe and effective usage of the latest technology in the imaging world.
You can sign up, and find more information HERE.
Special thanks to Nancy for letting me know this was available.
Sunday, September 28, 2008
Online Classes
In the world of the internet, more and more teaching institutions are going to either hybrid or fully online courses. I've been teaching online courses for a few years now, and here are some helpful tips for students of any kind for online success:
1) Log onto your online course every day. Doing this at least once a day will promote good communication of due dates, announcements, grades, or any changes in the lesson plans.
2) Check your email every day. Sometimes, when instructors have information for one or two students that does not apply to the entire class, the more private way of communicating these issues is through email.
3) Check due dates... and write them down somewhere on a calendar or daily planner to give you a place to look when your computer is not on. I know from personal experience that toward the end of a lengthy online course, the last thing I want to do is log onto my computer to check these. It's less effort to simply look at a calendar on the wall to know what you have to turn in for the day, and you can see what's coming for tomorrow.
4) Work ahead, if possible. The flexibility that online courses offer can be a pro or a con. Students who do not take advantage of the "work when you can" attribute to online courses can sometimes find it easy to procrastinate instead, thinking "I have until midnight to take this test... I'll start it at 11:00." Most courses will allow you to do your final lesson/exam at least a week before the end date of the course... if you have a course to follow, this could give you a week off to rest your noodle.
5) Ask questions. Simple, yes, but also realize that most online courses allow instructors a 24-48 hour response time for any questions. The #4 tip will help you with this... if you have a test due Friday, don't wait until Thursday to ask a question when you've had all week to look over the material. You will find yourself in a state of panic when it could have been avoided.
6) Communicate well... be specific when asking questions in an email. Make references to which book, page number, question number, on which chapter number, test number, assignment number, etc. that you are referring to. I commonly receive questions like "what was the answer to #3?" With a 48 hour response time, a lot of time can be wasted, and your answer may not be addressed, before the week's lesson is over.
7) Sign your email. Depending on how your online course is set up, the instructor might only receive your email address in the "sent from" box, and if you don't sign it, there's no way of knowing who the email is from. Make sure to sign your first and last name with each email. If you don't, all the instructor knows is that the email is from "awesomeradtech@yahoo.com." The other alternative is to create a free email account using your name as part of it.
8) Make sure you have the correct textbooks. Find out which editions you can use, and that you are purchasing the correct ones. Websites like Amazon.com will have some great deals that can save you money rather than buying new textbooks, but the extra effort must be made to purchase the correct editions, or any accompanying materials that the course requires like cd's, flashcards, or lab workbooks.
9) Browse the course well before any due dates. Make sure you are comfortable with the platform you are using... especially if you're not a "computer person." This will dramatically improve efficiency if/when you're in a time crunch and need information quickly.
10) Last, but definitely not least, take an online course before committing to any completely online program. If you are not sure that you are the type of student that is self-motivated enough to perform your assignments and diligently work without supervision, test it out. Take a prerequisite course at your local community college to see if you are the type of learner that is capable of doing an online course outside of the classroom. Some people just learn better inside a classroom and need that instructor/student face-to-face interaction... important to consider before committing to a 2 or 4 year dedicated online program.
Sunday, April 13, 2008
What is CQ2011?
Well, it is what someone who is probably a high school junior today will have to deal with if/when they decide to go to x-ray school after high school, and then attempt to renew their registry.
The new "Continued Qualification Requirement" is stated to take place for examinees taking the ARRT on or after January 1, 2011. Instead of requiring a 24 CEU biennium renewal, future examinees will be required to show some form of continued qualifications every ten years in order to renew their registration. What that exactly entails, we do not know yet, but the ARRT promises us that specifications will be available around April, 2009.
There is no current plan to begin this new requirement for individuals who have obtained their registry before January 1, 2011, and the traditional CEU biennium will continue to be observed. It is important to note that all new certifications acquired after this date will be subject to the new requirements and issued a time-limited certification.
A more detailed explanation, and a FAQ section can be found on the ARRT's website here.
The new "Continued Qualification Requirement" is stated to take place for examinees taking the ARRT on or after January 1, 2011. Instead of requiring a 24 CEU biennium renewal, future examinees will be required to show some form of continued qualifications every ten years in order to renew their registration. What that exactly entails, we do not know yet, but the ARRT promises us that specifications will be available around April, 2009.
There is no current plan to begin this new requirement for individuals who have obtained their registry before January 1, 2011, and the traditional CEU biennium will continue to be observed. It is important to note that all new certifications acquired after this date will be subject to the new requirements and issued a time-limited certification.
A more detailed explanation, and a FAQ section can be found on the ARRT's website here.
Friday, April 04, 2008
The name is Gorithm... Al Gorithm
If you haven't been introduced to Mr. Al Gorithm (algorithm) yet, I can assure you he's not sipping a vodka martini - shaken, not stirred. No, an algorithm is what you are selecting on CR/DR systems in the pre-processing moment when you pick the body part and position that you are about to perform.
The algorithm is a pre-programmed set of mathematical codes used by your imaging software that is responsible for the image appearance after processing. It basically gives you a "model" histogram that the image should look like, and matches the actual histogram produced by the image to the pre-programmed one. The algorithm controls the brightness and contrast (gradient processing), edge enhancement and smoothing (frequency processing), and even histogram equalization. Appendix for Digital Acquisition and Display: ASRT. Brittain, Burns, Nethery, Smith.
Here is a clinical situation you may be familiar with: You go to shoot a cross-table cervical spine for a patient who is in a collar and lying on a backboard. You use plenty of technique that SHOULD provide you with adequate density and an appropriate scale of contrast, and you might even get an optimal S-number of Exposure Index, but you have trouble seeing the C7-T1 space. If you've been around a seasoned technologist, or if you really understand computers, you may learn that changing the algorithm in post-processing may actually allow you to visualize that space without any additional exposure to the patient. You know that choosing "axillary shoulder" or "cross-table hip" will allow visualization of the part, so you go right ahead and do so, patting yourself on the back because you've upheld the standards of ALARA and you've managed to even save time getting the patient off of the backboard without having to repeat.
While those goals are excellent, and I commend you for striving to achieve them, here's the problem: This is a short-term solution to a long-term problem. Let's say one year down the road, the films that you took are requested with a subpoena as evidence in court. The patient may have been involved in an MVA and possibly had some long-term neck injury complications and could be suing... yadda yadda yadda. They call upon a specialist in the field (probably a Radiologist) to interpret your films in court that look so pretty, but say "cross-table hip" on the exam type. The defense lawyer questions whether or not the Radiologic Technologist who performed the exam really took Anatomy and Physiology, because obviously, the x-ray (as supported by the Radiologist on the stand) is in fact, of a cervical spine - not a hip. The films are thrown out as evidence as an insubmissible legal document because of errors.
Mr. Gorithm has seemingly bitten you in the rear while masquerading as your friend all this time. The real question here is how can we avoid this unpleasant circumstance? In order to answer that, we need to know who programs your algorithms for your CR/DR equipment. Usually, when this equipment is purchased and installed, a representative from the manufacturer provides the initial calibration and setup of equipment. It might be a good idea to write into a sales contract for this person to come back at a future date to update and/or make any additional changes that may have been unforeseen at the initial time of setup. Some larger hospitals may have someone on staff who could, in this situation, create a new algorithm for "x-table c-spine" that resembles the histogram of a "x-table hip." Just be aware of your service contract and its limitations to any non-manufacturer personnel making these changes... you don't want to void your warranty or any part of your contract.
Ideally, each projection or exam type should have its own working/calibrated algorithm to process it under. It may cost your facility a little bit of money to initially set this up, but how much will it cost the facility (or your patients) in the long run?
Saturday, March 29, 2008
What do you use?
I've only been on the east coast now for about two years, but I have noticed (at least in the facilities I've visited) that there is a huge difference in the type of Imaging Systems being used in the clinical setting.
I've taken x-rays now in three different states, and each of them have varied in the type of equipment used. Also, I have found examples of facilities in each state that have used more than one type of imaging system as well.
What I would like to do is obtain a general survey of what you are using at your hospital, imaging center, or urgent care center. I am posting a poll in the right hand column of this blog. If you could check off what type of combinations you are using, as well as post a comment to this entry stating what state you live in, I think it might give us all some perspective about how technology moves through the country, and who may be utilizing it the most.
Just for fun, check out the latest DR system from GE.
I've taken x-rays now in three different states, and each of them have varied in the type of equipment used. Also, I have found examples of facilities in each state that have used more than one type of imaging system as well.
What I would like to do is obtain a general survey of what you are using at your hospital, imaging center, or urgent care center. I am posting a poll in the right hand column of this blog. If you could check off what type of combinations you are using, as well as post a comment to this entry stating what state you live in, I think it might give us all some perspective about how technology moves through the country, and who may be utilizing it the most.
Just for fun, check out the latest DR system from GE.
Friday, March 14, 2008
It's not a memo... it's a mission statement.
After reading the details of an interesting study on Faculty Development Needs performed by the ASRT, I found myself distracted from my original interest in the results by the demographic data that I was reading to conclude that I am convinced that we will be in great need for educators in the United States for Radiography Programs in the near future.
Some interesting results for demographics of Full-time Faculty for Radiography Programs, as reported were the following:
Over 2/3 female
Approximately 92% caucasian
Average year for (R) certification was 1983
Average year born was 1960 (or avg. age 47)
Average # of years in education = 4
When asked when they were planning on leaving the education profession, about 1/5 of full-time faculty (and 1/4 of program directors) stated they would be leaving within the next 5 years, and half of faculty/program directors would be leaving within the next 10 years.
It is obvious from the collected data quoted above that the majority community of Radiography Educators is approaching retirement age within the next decade. Having been very recently affected by instructor retirement at my own institution, it is resoundingly clear that with all of the accumulated years of experience that these instructors have acquired, we all have some distinguished shoes to fill.
So why am I talking about this on a blog mainly visited by students? Well, over the next 5 years, those of you who will be graduating from Radiography Programs across the country will be the prime position to jump aboard the pendulum downswing of the educational market demand. Now is the time to be thinking about your next step; what you want to do after you successfully acquire your ARRT Registration, and have a few years of technologist experience under your belts. If you have any interest in education, it might be beneficial for you to research the possibility of steering your careers toward education for the upcoming time of need.
It doesn't take long in this field to notice the symbiotic relationship between educators and technologists. What I have yet to experience (at my ripe young age of 30) is how educational standards will be maintained when such a large percentage of upcoming retirees with their vast levels of experience both in Radiography and Education will be passing the torch. Now is the time for us youngsters and newbies in the field to step it up; to display our enthusiasm for our field, to learn as much as we can from these great contributors to our profession, and to move forward in a fashion that honors those before us.
Wednesday, February 27, 2008
Contrast in Review
It's always a good idea to review topics like contrast that have so many of those arrows going this way and that. It reminds me of one of those street signs in Europe that you see on the movies where 10 roads come together at one intersection, and you can't find your destination because the signs are written in a foreign language. Hopefully, the concept of contrast does not remain a foreign language to you. Still, we can look at how changes in exposure factors effect contrast:
Changes in mA, time, or overall mAs should not affect contrast at all. It is important to remember that you must have adequate density (optimal or acceptable) in order to properly evaluate contrast. So it can be said that if you have excessive density - too dark, or insufficient density - too light, then you would experience a decrease in contrast.
We know that kVp is inversely related to contrast, and is our primary controlling factor of contrast. As we increase kVp, our contrast decreases.
Filtration is used to increase the average energy of our beam, or "harden" the beam. As we add filtration, the average kVp of photons getting through is higher, so the contrast will decrease. It's similar to increasing your kVp slightly without any other changes.
Field size has a dramatic effect on contrast. If we use the entire field size on a 14x17 cassette on a lateral l-spine, we would be irradiating much more tissue than we need to, causing tons of scatter and lowering contrast. So when we decrease field size (collimate), we are avoiding unnecessary tissue irradiation, thereby reducing the amount of scatter produced, which reduces fog reaching the film, and improving contrast - all while withholding the standards of ALARA - give yourself a pat on the back.
When we have increased motion on our films - the ability to distinguish a very light area from an adjacent dark area on the film becomes blurred. When there is less of an ability to "distinguish shades of gray from one another" contrast has decreased, even though technical factors have not changed.
Patient size affects contrast quite a bit as well. If I take a KUB on a 20cm abdomen and have optimal contrast, then I go to take a KUB on my next patient with a 35cm abdomen, I am increasing the thickness of tissue, which will absorb more of my photon energy, reducing image contrast.
Now we have our grid ratio - thank goodness for grids. As I increase in grid ratio, the quantity of scatter-absorbing lead increases, as well as the hight of the lead strips. As the lead strips become taller, their propensity to allow even slightly scattered photons to pass through decreases. So an increase in grid ratio means an increase in image contrast.
Focal spot size has no effect on contrast... one less thing to worry about.
SID - well, two less things to worry about - no effect on contrast.
OID has some effect on contrast (air gap technique). As you increase OID, the percentage of scattered photons reaching the film decreases due to their angle of scatter. If a photon is only slightly scattered, you can eventually increase OID enough so that the scattered photon will miss the film. This reduces scatter reaching the film, therefore increases contrast.
Developer time/temperature will affect contrast as well. This goes back to what we discussed with having the appropriate density before we can properly evaluate image contrast. If the developer temp or time are too short, then your image will be too light, therefore have decreased contrast. If the developer temp/time are too high, your image will be excessively dark, therefore image contrast is still decreased.
Last but not least, we have film/screen speed. I waited until last because there seems to be some discrepancies between textbooks on this one. One textbook says that there is no effect, while another textbook says that an increase in screen speed produces an increase in image contrast. It goes on to mention that the increase in contrast is probably not enough to visibly see, or to make much of a difference in your optimal image, but it does occur. I would actually like to see what everyone can find from their own sources and post in the comment section here. I've only looked at three books myself, but I'm all for having as much support as possible.
Friday, February 01, 2008
Filtration
What is a filter? Well, if you're a coffee drinker, you are familiar with filters. A nice brew is created by placing a filter in the coffee maker and filling the filter with ground coffee beans, allowing the desired coffee (created when hot water soaks the grounds) to flow through to the pot, while preventing the unwanted portion (the grounds) from trickling down. This is not so different from radiographic filters at all.
An x-ray filter is composed of Aluminum equivalent material (Al - not to be confused with Pb for shielding) and is between the target and the patient for the purpose of preventing unwanted photons (the grounds) from passing through while allowing the desired photons (the coffee) to pass through toward the patient.
So which photons do we want to keep and which ones do we want to get rid of? Our duty as Radiologic Technologists is to keep radiation exposure levels of the patient at a minimum (ALARA standards). So, in any x-ray exposure, there is a portion of the beam that will be at a very low energy for the part being x-rayed. It is so low, that it does not even contribute to the useful beam, and it ends up getting absorbed in the patient contributing to radiation dose - BAD photon!
A filter allows us to remove a majority of the bad photons while allowing the good photons (higher energy) to get through to the film. The line of thinking goes something like this: "If the low energy photons are not going to contribute to our image anyways, why not remove them?" Take a look at the picture of an unfiltered beam:
Here I have randomly selected five photons with varying energy levels (we all know that just because we select 70 kV, it doesn't mean all photons produced are at their peak). To calculate the average energy of the beam using these photons, you add them all together and divide by 5, which gives you an average energy of 50 keV. The 30 and 40 keV photons are probably going to be absorbed by the body to contribute to radiation dose to the patient. Now, lets look what happens when we add filtration:
Notice, the two lower energy photons are removed, and the remaining photons have a higher average energy of 60 keV. This is also referred to as "hardening" the beam. Note that any time you add filtration without changing any other factors, you are reducing the intensity of your beam, so an increase in technique is always required when adding any absorbent material. The resulting energies are shown in the following graphic representation of exposures made at 120 kVp:
HVL - half value layer is any amount of material (or in this instance, filtration) that reduces the intensity of your beam to half its original value. Consequently the TVL (tenth value layer) is the amount of material that reduces the intensity to one tenth the original value, and so on.
Types of filtration:
Inherent filtration is any filter that is present as part of the radiographic equipment, and usually includes the glass envelope surrounding the tube, as well as any oil around it. This usually makes up about .5 - 1.0 mm Al equivalency.
Added filtration is just as it is described - anything added to what filtration already exists within your equipment. It usually resides between the tube housing and the collimator box. See the following picture from "Principles of Radiographic Imaging" Carlton/Adler 4th edition:
Total filtration = inherent filtration + added filtration. According to the National Council on Radiation Protection (NCRP), total filtration must be a minimum amount depending on the kVp range you are using:
Below 50 kV - 0.5mm Al
50 to 70 kV - 1.5mm Al
Above 70 kV - 2.5mm Al
Compensating filters are for another post... to be continued...
Tuesday, January 29, 2008
Reminders:
American Registry of Radiologic Technologists
A reminder to those of you who are licensed that as of this month, January, 2008, all CEU's acquired after the 1st of this month must be "category A" in order to count toward your license renewal. According to the ARRT, in order to be considered "category A," continuing education credits must be as follows:
* have been approved by a Recognized Continuing Education Evaluation Mechanism (RCEEM), and/or
* meet the definition of approved academic course, and/or
* be for certification in advanced-level CPR, and/or
* be earned through passing additional certification exams.
American Society of Radiologic Technologists
I would have liked to post this one sooner, but the ASRT deadline for scholarships is February 1, 2008. You can acquire scholarships for any discipline or even for extended education beyond your Associates Degree or Radiologic Technologist Registration by viewing the ASRT website.
A reminder to those of you who are licensed that as of this month, January, 2008, all CEU's acquired after the 1st of this month must be "category A" in order to count toward your license renewal. According to the ARRT, in order to be considered "category A," continuing education credits must be as follows:
* have been approved by a Recognized Continuing Education Evaluation Mechanism (RCEEM), and/or
* meet the definition of approved academic course, and/or
* be for certification in advanced-level CPR, and/or
* be earned through passing additional certification exams.
American Society of Radiologic Technologists
I would have liked to post this one sooner, but the ASRT deadline for scholarships is February 1, 2008. You can acquire scholarships for any discipline or even for extended education beyond your Associates Degree or Radiologic Technologist Registration by viewing the ASRT website.
Sunday, January 27, 2008
Accuracy of ARRT Preliminary Test Scoring
I just received a comment on the "In the News" post asking about the accuracy of the preliminary results that the ARRT is going to be giving when graduates finish their Radiography Registry Examination. Since I only wish I had all the answers, I figured I would take my own private little survey of the students who read this blog. There is now a poll on the right-hand column of this blog for those of you who have received preliminary results to mark your results on.
I would not expect to see a variation much over 10% between the two, and here's why: If there are 20 pilot questions out of 200 that don't count toward your score, and they happen to factor those into the preliminary results that they give you on test day, that's 10%. There could be other variables as well that would make them more inaccurate. Since they're planning on adding new content to the Registry, I would expect there to be some inconsistencies at first with clarity and/or presentation of a new question or two. As an instructor myself, I know what answer I'm hoping the students will choose, but I have to write an appropriate question in order to lead the well-studied test taker to the right selection. But I am only one person, and the mighty ARRT has a huge panel of experts, test writers, many more years of experience writing tests, and the ability to implement pilot questions, so they might not even consider this an issue.
All in all, I'm excited to see what you all post on the poll. If there's a wider margin than 10%, feel free to post a comment or email me and I can add a new category to vote on within the poll. Just in case you don't know how to calculate percentages, you can... wait, your Radiography graduates, you know how to do that! :-)
Wednesday, January 23, 2008
To Grid or not to Grid...
...that is the question. We all learned (or are in the process of learning) in school to use a grid on anatomy over 10 cm in part thickness or on techniques that require more than 70 kVp. But when you get right down to it, most technologists are not using grids for their portable chest x-rays. Why could this be? I'm so glad you asked... most grids have the lead strips running along the long axis of the grid. If you practice angulation perpendicular to the sternum (see prior "Lordotic Much" post), then you will find yourself with tons of grid cutoff when performing a crosswise cassette/grid placement. Having tried this on Kodak and Fuji systems with a lengthwise cassette, I can honestly say that the images are quite better. I'll give you one guess which of the following images was taken non-grid vs. with an 8:1 grid:
I know what you're thinking... "so what do I do when I have a crosswise chest x-ray to perform?" Well, you're pretty much out of luck unless you can convince your radiology department to purchase a few SD (short dimension) grids. Some companies manufacture these, and as we all know, grids can be very expensive, so take extra special care of these. The grid lines are arranged along the short axis of the grid to allow for crosswise placement, and to give the technologist the ability to angle cephalic or caudal without having those unsightly grid lines on your finished radiograph.
On a special note to anybody planning on purchasing these grids, make sure to check two aspects of your CR equipment before purchasing them. First, you need to see how your cassettes are scanned by the image reader (the laser will most often scan the photostimulable phosphor plate perpendicular to the direction of travel). If the CR system scans along the short axis of the phosphor screen (the same axis as the SD grid), then you want to make sure that the grid frequency (not ratio) is slightly higher than the scan frequency. This will prevent an alaising/moire artifact shown here:
Be sure to check with your quality assurance team to ensure that you are purchasing the proper grids at the right grid frequency.
I know what you're thinking... "so what do I do when I have a crosswise chest x-ray to perform?" Well, you're pretty much out of luck unless you can convince your radiology department to purchase a few SD (short dimension) grids. Some companies manufacture these, and as we all know, grids can be very expensive, so take extra special care of these. The grid lines are arranged along the short axis of the grid to allow for crosswise placement, and to give the technologist the ability to angle cephalic or caudal without having those unsightly grid lines on your finished radiograph.
On a special note to anybody planning on purchasing these grids, make sure to check two aspects of your CR equipment before purchasing them. First, you need to see how your cassettes are scanned by the image reader (the laser will most often scan the photostimulable phosphor plate perpendicular to the direction of travel). If the CR system scans along the short axis of the phosphor screen (the same axis as the SD grid), then you want to make sure that the grid frequency (not ratio) is slightly higher than the scan frequency. This will prevent an alaising/moire artifact shown here:
Be sure to check with your quality assurance team to ensure that you are purchasing the proper grids at the right grid frequency.
Monday, January 14, 2008
kV, mAs, and density
One of the more difficult topics for first year students is the correlation between kV and density. Once you think you have this concept down, including the 15% rule and the subsequent lab experiments, this topic gets revisited a number of times throughout the entire x-ray program, and some very good questions about kV, mAs, and density typically arise. For instance:
Does the number of photons increase as kV increases?
Well, yes... let me explain first by clarifying that the number of electrons produced at the cathode does not increase - that is controlled only by mA while the duration of production is controlled by the time.
Now, let's say I have a technique of 65 kV and 10 mAs for a knee x-ray. A certain number of electrons are converted to x-ray photons at the anode during that exposure, and then a certain number of primary photons are converted to secondary and tertiary photons and so forth when they interact with the patient until one of two things will happen to all photons:
1 - they will leave the patient as scatter or expose the film
2 - they will lose potential difference and become absorbed in the patient
Now let's focus on the photons in the latter category... when we increase kV, we know that more photons reach the film because they have increased energy to penetrate the patient, but something else happens. There will still be a percentage of photons that will be absorbed in the patient, but it will not be as high of a percentage as the 60 kV exposure. You will now, at 75 kV for instance, have more energy even in the photons that are absorbed, to ionize tissue before those photons deposit all energy into tissue.
To clarify, let's say we have a characteristic interaction between a primary x-ray photon and an atom of carbon in the patient. We'll also say that this photon carried 75 kV of potential difference. The binding energy of the k shell for carbon is .28 keV, so we're left with a secondary x-ray photon of 74.72 keV with the ability to produce the same reaction approximately 267 more times (75/.28) before it is absorbed and each reaction produces more photons that will be absorbed. If the same series of reactions occurred with the 65 kV exposure, then you would only have a possible 232 of these identical interactions before the photon's energy is absorbed.
Keep in mind that this is only one example of a photon's interaction with matter, and there is always that randomness applied to how they react. If you haven't studied compton, photoelectric, or characteristic interactions yet, don't feel bad if you didn't understand the last paragraph. Just remember that when a photon interacts with matter, other photons are typically produced, or electrons are ejected that can ionize adjacent atoms as well, and increasing kV will increase the number of interactions that occur before the photons are absorbed.
Does the number of photons increase as kV increases?
Well, yes... let me explain first by clarifying that the number of electrons produced at the cathode does not increase - that is controlled only by mA while the duration of production is controlled by the time.
Now, let's say I have a technique of 65 kV and 10 mAs for a knee x-ray. A certain number of electrons are converted to x-ray photons at the anode during that exposure, and then a certain number of primary photons are converted to secondary and tertiary photons and so forth when they interact with the patient until one of two things will happen to all photons:
1 - they will leave the patient as scatter or expose the film
2 - they will lose potential difference and become absorbed in the patient
Now let's focus on the photons in the latter category... when we increase kV, we know that more photons reach the film because they have increased energy to penetrate the patient, but something else happens. There will still be a percentage of photons that will be absorbed in the patient, but it will not be as high of a percentage as the 60 kV exposure. You will now, at 75 kV for instance, have more energy even in the photons that are absorbed, to ionize tissue before those photons deposit all energy into tissue.
To clarify, let's say we have a characteristic interaction between a primary x-ray photon and an atom of carbon in the patient. We'll also say that this photon carried 75 kV of potential difference. The binding energy of the k shell for carbon is .28 keV, so we're left with a secondary x-ray photon of 74.72 keV with the ability to produce the same reaction approximately 267 more times (75/.28) before it is absorbed and each reaction produces more photons that will be absorbed. If the same series of reactions occurred with the 65 kV exposure, then you would only have a possible 232 of these identical interactions before the photon's energy is absorbed.
Keep in mind that this is only one example of a photon's interaction with matter, and there is always that randomness applied to how they react. If you haven't studied compton, photoelectric, or characteristic interactions yet, don't feel bad if you didn't understand the last paragraph. Just remember that when a photon interacts with matter, other photons are typically produced, or electrons are ejected that can ionize adjacent atoms as well, and increasing kV will increase the number of interactions that occur before the photons are absorbed.
Wednesday, January 09, 2008
Hmmmmm...
After quite some time of hardcore thinking, and having been a member of several radiography forums and reading in the blogs around the world dedicated to radiography, I am leaning toward the re-dedication of this blog to be geared more toward students and the topics that are underway in the midst of their prospective courses of study.
I think it may be beneficial to open discussion about some of the more abstract concepts that can sometimes be glazed over in the classroom that there might not have been time to thoroughly investigate during lecture. That being said, feel free to ask questions, submit topics or comments, offer input, and share experiences here.
Updates to Curriculum
In the next few years, the ARRT and ASRT will begin to employ some additional topics including more direct digital and CR equipment on the content specs and in the Registry examination. Efforts are being made in Radiography programs across the country to incorporate these changes to better prepare students for their boards after graduation. There are going to be some pilot questions regarding image acquisition, construction and function of the CR processor and photostimulable phosphor screen, and DR image receptor. Computer basics and networking basics may appear, as well as technical factor selection and a whole new slew of image artifacts with digital imaging.
Those of us who have never had an introduction to this material might benefit from continuing education courses offering these topics. For instance, studies are showing with CR and DR that scale of contrast is not primarily controlled by kVp anymore, as we are all used to with film/screen imaging systems, but it is mainly determined by the algorithm selected at your QC station (chest/hand/c-spine etc.), with kV having a wider range of usability, and becoming a secondary factor. The possibilities for lowering patient dose with administration of higher kVp and lower mAs is highly effective. This is only one of the many changes that come with updates to our imaging systems.
After attending a digital radiography seminar for educators at UNC in Chapel Hill, I can honestly say the changes to what we've studied and known in the past about radiography are extreme. I challenge everyone who is reading this to embrace those changes. In order to stay competent in our highly technological field, we must all strive to keep up with this technology, and to continually try to adhere by the standards of ALARA, keeping dose low with image quality high.
Those of us who have never had an introduction to this material might benefit from continuing education courses offering these topics. For instance, studies are showing with CR and DR that scale of contrast is not primarily controlled by kVp anymore, as we are all used to with film/screen imaging systems, but it is mainly determined by the algorithm selected at your QC station (chest/hand/c-spine etc.), with kV having a wider range of usability, and becoming a secondary factor. The possibilities for lowering patient dose with administration of higher kVp and lower mAs is highly effective. This is only one of the many changes that come with updates to our imaging systems.
After attending a digital radiography seminar for educators at UNC in Chapel Hill, I can honestly say the changes to what we've studied and known in the past about radiography are extreme. I challenge everyone who is reading this to embrace those changes. In order to stay competent in our highly technological field, we must all strive to keep up with this technology, and to continually try to adhere by the standards of ALARA, keeping dose low with image quality high.
Wednesday, October 24, 2007
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 :-)
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 :-)
Saturday, September 22, 2007
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.
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.
Friday, September 21, 2007
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.
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.
Saturday, September 01, 2007
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.
Saturday, August 11, 2007
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.
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.
Friday, August 10, 2007
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!
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!
Saturday, July 21, 2007
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...
Tuesday, July 17, 2007
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.
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.
Thursday, July 12, 2007
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.
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.
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