The Importance Of Radiopaque Markers In Digital X-Ray

Radiopaque Anatomical Markers

Radiographers are taught from day one in school to place radiopaque anatomical markers within the primary beam of radiographs.  We do so as a method of “best practice” to properly distinguish the patient’s right from left on the radiographic image per legal requirements. Conditions like dextrocardia (when the heart is positioned on the right instead of the left) and situs inversus (when all of the internal organs are on the opposite side compared to normal anatomy) exist which can easily be misinterpreted and would normally cause a technologist to inappropriately orient the image to appear similar to normal anatomy.  But when radiographs misrepresent right from left, this presents a huge risk for medical errors.

Computed Radiography & Digital Radiography

When Computed Radiography and Digital Radiography entered the scene, radiologic technologists were provided with a method of digitally annotating right and left.  This further led some to question the necessity of placing radiopaque anatomical markers within the primary beam of each radiograph.  If you’re like me, you’ve more than likely witnessed a decline in the use of markers in your radiology department but make no mistake; they are more necessary now than ever with the introduction of digital radiography.

A Cautionary Tale

Several years ago when I was working with a new Computed Radiography system in a hospital, I was on portable-duty which consisted of 50-60 portable chest and abdomen exams per day on average.  Another technologist, who was assigned the “float” shift, was asked to rotate where needed within the department.  I asked this technologist for help with a STAT portable chest x-ray in ICU around mid-morning, and by mid-afternoon I found myself in the Chief Radiologist’s office with the Radiology Director and Manager.  The door was closed, faces were red, and it was uncomfortably quiet.

After what seemed like an eternity, the Chief Radiologist displayed a portable chest radiograph on his monitor and asked “do you recognize this exam?”  I looked for several seconds and said, “No, I actually don’t.”  They looked at one another confused, and then asked me to critique the image.  I started to go through my image critique steps learned in school one by one, noting the presence of what I thought might be a pneumothorax, and they stopped me when I said there was no marker present.  The radiologist then asked me, “How would you know if this exam was oriented properly on the screen?”  I rattled off some details that would give anyone clues, but when I discussed the location of the heart, he stopped me again.  He horizontally flipped the image and stated “is this hung correctly?”  Ultimately, I concluded that there was no way to know whether the exam was hung appropriately due to lack of a radiopaque anatomical marker or a blocker (which we could use in film/screen imaging to determine if we knew the projection – PA vs. AP).

They all looked at one another again and the radiologist asked me “Did you perform this radiograph?”  I did not remember viewing an image similar to that one during my exams performed that day, so I let them know I didn’t remember performing it.  They asked me if anyone was helping me throughout the day, and my heart sunk, knowing I had to name the only person I had asked for help that day.  They invited me to exit the room and resume my shift.  My manager encouraged me to continue using my markers, and he informed me he would follow up with me before I left for the day.  The door closed behind me.

Later that afternoon, I was called back into the same room that displayed the same chest radiograph.  The radiologist was a bit less intimidating, but not much.  He explained to me that the radiograph indeed displayed a pneumothorax… a “tension pneumothorax.”  He asked if I knew what that was, and at the time I did not.  A tension pneumothorax occurs when one lung is punctured and air enters the pleural cavity around the punctured lung.  The “tension” portion occurs because air entering is not allowed to escape the pleural cavity, and the mediastinal structures as a result are shifted to the opposite side (in this case, from the patient’s left to their right).

After their investigation, it was concluded that the technologist exposed the image without placing a radiopaque marker within the primary beam.  When the image displayed at the computer terminal during processing, it was most likely appropriately displayed.  Due to the appearance of the mediastinal organs on the patient’s right side, the technologist viewed prior radiographs to ensure the patient had normal anatomy (which he confirmed).  He then mistakenly flipped the image horizontally so that the heart appeared on what he thought was the patient’s left side, digitally annotated a “left” marker, then sent the image to the radiologist for dictation.

The radiologist, upon viewing this STAT exam, called the physician who was in ICU and informed them that the patient had a pneumothorax on the right side, although it was actually a tension pneumothorax on the patient’s left.  Because the technologist had inappropriately flipped the image, the ordering physician inserted a chest tube on the wrong side, into the unaffected lung, causing further complication which lead to a Code Blue being called and a much longer recovery process for the patient who was already undergoing treatment for several other problems.

I found out I was originally called into the Chief Radiologist’s office immediately following a 30-minute scolding by that patient’s physician who inserted the chest tube on the wrong side because of an error made in the radiology department.  The patient eventually recovered, but imagine what could have happened as a result of the technologist’s error.  I was glad to be off the hook, but I never found out if the technologist was disciplined or if charges were ever pressed against the hospital.

Lessons Learned

Having experienced something like this, it is easy to see the importance of radiopaque markers on a radiograph.  It is discouraging to know that many departments see a decline in their usage simply because we can place one there after the image is processed; because it’s easy.  It may be true that it is more difficult to remember to place a marker or to remember to simply bring your markers to work with you, however, It is my opinion that allowing this to happen not only encourages error, but causes liability for the technologist, radiologist, and institution that is providing radiographic services.  It should be a goal to have radiopaque anatomical markers on 100% of radiographs.  It is required for images to be admissible in a court of law, and it truly is “best practice.”

Risks vs. Benefits

Whether images need to be repeated if a marker is occasionally not visible on an image, warrants a risks vs. benefits discussion with on-site personnel including the radiologist/s.  Technologists can be held accountable, however, during evaluations and upon the occurrence of failure to use these markers.  Furthermore, it is important for employers to encourage and enable technologists to use these markers and have a quality assurance process with follow-up.  It would also be wise to consider other options such as purchasing disposable, single-use markers which can be utilized for isolation cases which infection control becomes an issue, or for when a technologist misplaces their markers.  There are tools at our disposal which are cost-effective that can prevent situations like the one mentioned earlier.

About the Author 

Jeremy Enfinger is an experienced Radiologic Technologist, Radiography Program Instructor, and published author. He has served in leadership roles in hospital, outpatient and academic settings. His experience includes writing examination questions for the national ARRT Radiography Exam and multiple – modality training. He continues to pursue excellence in education and patient care. An avid blogger, Jeremy strives to promote standards of excellence in imaging through his online community with the sharing of veteran tips and techniques for high-quality imaging.

Free eBook

 

For any radiologic technologist looking to make improvements and fine-tune their image critique skills; this is a must-have resource. To receive your copy first, sign-up for the “Topics in Radiography” email list and you’ll be able to download the book for free on April 18, 2015.

 

 

 

Radiation Protection During Mobile Exams

Do you wear a lead apron during portable exams?

I have found in my years of experience as a radiologic technologist that practices vary from one radiologic technologist to the next.  Of course, we utilize some form of radiation protection when it comes to using a c-arm for mobile fluoroscopy in the operating room.  Fewer people wear lead when performing plain film images during surgical procedures.  And most don’t seem to worry about radiation protection during routine portable exams like chest x-rays and abdomen films.

Why is this?  

We learn in school that lead shielding is required when performing these exams.  For those of you who do not wear radiation protection for mobile exams, I am about to show you something which may cause you to change the way you prioritize wearing radiation protection apparel.

For some context, I want to step back in time, when Computed Radiography (CR) was first implemented at a hospital I was a clinical instructor for.  My job was to accompany student technologists while they performed their exams and to educate and evaluate.  Having never been to the operating room at that facility, I was given the opportunity to tag along with one of the staff techs who had been observing my student for the day.  They were assigned to perform a cross-table lateral lumbar spine image during a discectomy.

I watched as the staff technologist carefully walked around the table, being mindful of the sterile field, and positioned the draped image receptor next to the patient.  My student used the portable x-ray machine to align a horizontal beam to include the lumbar spine for the prone patient.  When they were finished setting up, they indicated to the O.R. staff in the room that they were ready to expose the image.  All of them, including the physician left the room while the three of us from the radiology department stayed to make the exposure.

We had taken two CR image plates into the room with us.  One was positioned next to the patient, and the other had been placed against the wall behind us.  The student made the exposure, extending the full length of the cable that attached the exposure switch to the portable x-ray machine, which was about 12 feet.  The staff technologist and I backed up to the wall behind us – I would guess an additional 3 feet behind the student technologist who exposed the image.  We all wore lead aprons.

Upon returning to the radiology department to develop the image, the student made a mistake that every technologist has done in their career.  He was carrying both the exposed image plate of the lumbar spine image as well as the unexposed image plate that had been resting against the wall behind us, and he forgot which one was the exposed plate.  The logical solution was to process both image plates under the “lateral lumbar spine” algorithm and discard the image that was not exposed.

The first image was not the lumbar spine image we had hoped it would be.  Instead, something peculiar appeared on the monitor in front of us as the scanner slowly revealed more and more of the image during processing.  Once the entire image had been scanned and the processing the algorithm was applied, it was clear that this was an image of a lower leg (a portion of the tibia and fibula).

Thinking we had come across someone else’s image plate that had been exposed for a different patient (and thankful we did not use that plate to image the lumbar spine), we began asking around the department to see if anyone was missing a tib-fib image from any of their exams.  No one was missing an image.  I decided to examine the image further on a PACS monitor for larger viewing.  The image quality was poor, and the resolution was horrible.  The exposure indicator proved that the image was slightly over-exposed.  I then realized what I was looking at.  This was the cassette that was leaning against the wall in the operating room approximately 15 feet from the patient that was x-rayed.  If you recall, the staff technologist and I had backed up against the wall prior to the exposure being made for the lumbar spine.  This was an image of the staff technologist’s leg, which was positioned just a few inches in front of the image plate during the lumbar spine exposure.  This was purely created by scatter radiation from the exposure we took in surgery.

Here are some examples of images created solely from scatter radiation in an experiment based off of lessons learned from this experience:

S# was 1190 at 8 foot distance from lateral lumbar spine phantom, which indicates about 1/4 the exposure required to produce a diagnostic hand x-ray

S# was 980 at a 6 foot distance from lateral lumbar spine phantom

I also decided to x-ray a chest phantom to simulate a portable chest x-ray using 120 kVp and 5 mAs. The following image was created from scatter radiation from about 10 feet away from the chest phantom.

S# was 2780

Though the last image produced from the chest phantom didn’t receive nearly the exposure as the one from the lumbar spine phantom, it is still obvious that there is enough radiation to penetrate the fingers from 10 feet away.  Now that you’ve read this and seen evidence of the radiation we work with every day as a radiologic technologist, are you going to change your practices?  If you already use radiation protection for your mobile exams, will you encourage your co-workers and student technologists to adopt these habits?

Registered radiologic technologists vow to keep radiation dose “As Low as Reasonably Achievable” (ALARA).  It is our duty not only to protect patients from the harm that can be caused by radiation, but to protect yourself and your co-workers from it as well.  Let us not forget the three basic principles of radiation protection; time, distance and shielding.  Keep the amount of time you are exposed to radiation low.  Keep as much distance from a radiation source as possible.  And finally, use shielding, including during mobile examinations.  Consistent application of all three of these basic principles of radiation protection will keep you, your patients and your co-workers as safe as possible.

About the Author 

Jeremy Enfinger is an experienced Radiologic Technologist, Radiography Program Instructor, and published author. He has served in leadership roles in hospital, outpatient and academic settings. His experience includes writing examination questions for the national ARRT Radiography Exam and multiple – modality training. He continues to pursue excellence in education and patient care. An avid blogger, Jeremy strives to promote standards of excellence in imaging through his online community with the sharing of veteran tips and techniques for high-quality imaging.

Additional Reading Written by Jeremy Enfinger via Topics in Radiography Blog

Experiments with Scatter Radiation (original post from 2009 – with updated images and technical factors)

Reducing Radiation Dose in Diagnostic Radiography

Podcast: How To Communicate Radiation Risks To Patients

What Everyone Should Know About Digital Radiography

Gold Standard Cleaning For X-Ray Aprons & Lead Wearables

What Does Gold Standard Cleaning Look Like For X-Ray Aprons And Lead Wearables?

Thus far in this lead apron based blog series, we have examined the infection issues and concerns associated with contaminated lead x-ray aprons and the science behind how staff members can easily test such surfaces for contamination using ATP testing.

This third blog entry will examine methodologies and practices utilized by clinical staff and facilities in the “cleaning” and maintenance of these protective lead wearables, and also explore what “cleaning” such a surface really entails. In discussing bioburden levels in the previous blog, we addressed how one cannot judge cleanliness on a surface by appearance alone.  Let’s take a deeper dive into what it means to truly clean and sanitize these protective, lead garments.

Survey Says…

In researching the topic, speaking with professionals at symposiums and inquiring with colleagues and peers, there is little consistency across the continuum of care with how these garments are cleaned and/or serviced. Shockingly, a number of Radiology, Cath Lab and Operating Room staff have lamented that such surfaces “never” get cleaned, while other staff and administrators have shared that such surfaces are sometimes cleaned, “when the case load is light on a Friday” or “on the midnight shift by the environmental services department.” Both patient and staff safety are at risk due to lack of staff compliance and clinical efficacy issues posed through improper cleaning practices.

Online research lead to a few administrators sharing that they ran these lead aprons through a cart washer, which lead manufacturing companies clearly advise not to do. Clinicians have also shared that they try to use products such as Lysol or Febreeze to “eliminate the odors” yet admit the lead wearables still aren’t “clean.” One of the more popular concepts considered in attempting to clean and service these wearables entails the discussion of “using sanitizing wipes” on such high-touch surfaces.  Unfortunately, the use of these wipes alone does not properly clean and sanitize the garments.

Pesky Directions

There are a number of sanitizing/disinfecting wipes on the market that some clinicians claim to use on lead aprons and wearables. When taking a closer look at the labels on these products, one may very well discover that most wipes are actually not recommended for use on lead wearables. Additionally, some wipes contain bleach and corrosive agents, which are both advised not to be used on aprons, according to the companies that manufacture them. A majority of the wipes on the market today are indicated for use on “non-porous” surfaces such as tables, bed rails, door handles, etc. rather than a porous surface such as a nylon covering of a lead wearable. Though the use of wipes might afford convenience to the user, the real issue with doing so lies in their clinical inefficiency in successfully cleaning the surface, not to mention completely removing any bioburden.

Wax Then Wash?

If your car had dirt, road tar and bird droppings on it, would you attempt to wax it in that condition?

For best outcomes, you would first clean and remove those elements before attempting to wax the car.  The same is true for other surfaces, including lead wearables.  Professionals who routinely assess bioburden understand the importance of a proper cleaning before sanitizing or disinfecting an item.  If an item is not properly cleaned and organic matter remains, nutrients also  remain to better foster the growth of surviving bacteria or future bacterial contamination.  This is by definition a risk factor for increased hospital associated infections.

All You Can Eat Buffet

In watching the news of late, one can gather that the world of microbiology is ever changing.  Bacteria are highly adept at persisting.  Through changes in their DNA they can gain antibiotic and/or antiseptic resistance, and these changes can happen through mutations or through integration of foreign DNA, but where would they find foreign DNA?  When bacteria die and the cells break open, then the DNA is accessible to the remaining bacteria.

The Problem with Sanitizing and Disinfecting Wipes

When facilities only use wipes on a surface and don’t completely remove the debris, they are in essence creating an “all you can eat buffet” for the surviving bacteria to thrive upon. If the dead bacteria had antibiotic or antiseptic resistance markers, now that DNA is fair game for susceptible bacteria to gain resistance!   In fact, numerous studies have shown that certain bacteria can pick up various genes from different species that makes them more pathogenic (either by making it antibiotic resistant, antiseptic resistant, or by allowing it to survive in a host better).

Layers Of Bacteria? Gross?

As if that wasn’t scary enough, what if I told you that some bacteria could gain antibiotic and antiseptic tolerance simply by growing?  (IT IS TRUE!)

Some bacteria can attach to a surface (particularly porous or textured surfaces such as lead wearables) and as they grow and form groups of bacteria (colonies) that can then form a biofilm.  Biofilms are clusters of bacteria that have attached and produced an extracellular polymeric substance (EPS) which are essentially a protective coating.

Extracellular Polymeric Substance (EPS)

EPS consists of DNA, proteins, lipids (fats) and polysaccharides (sugars).  This coating protects the bacteria inside the human body from cells that can either tag the bacteria for destruction or destroy the bacteria outright.  Externally (on a surface) it can protect the bacteria from anti-microbial drugs or antiseptic agents.  In fact, bacterial biofilms are 10 – 1,000 times more resistant to antibiotics than there standalone bacterial counterparts.  Their EPS is essentially a bacterial Teflon coating.  This Teflon coating only gets stronger when multiple species of bacteria co-inhabit the same biofilm, and if these attributes weren’t scary enough, bacteria in a biofilm can sense their microenvironment and may even produce toxins while in a biofilm that they wouldn’t normally produce.

Biofilm Life Cycle

Like all living things, biofilms have a life cycle, and a part of that life cycle involves dispersion of some bacteria that are then free to go and attach elsewhere, including in a human host. In 2007, the National Institutes of Health estimated that approximately 80% of chronic infections were biofilm related; thus, biofilms remain a serious problem in many facilities. When surfaces such as the nylon covering of a lead wearable are not cleaned properly, it allows different bacteria to begin to congregate.

Layers of Bacteria

Thinking this all sounds like something from a fictional book or movie, as if biofilms can only exist in some weird lab conditions or in some rare disease?  Nope!!!!

The most common example of a biofilm is one that everyone is probably familiar with, but may not realize is a biofilm, is dental plaque!  Biofilms are so hard to remove from surfaces that companies have spent millions of dollars trying to prevent their formation.  If you think about dental plaque, it makes sense.  We brush our teeth twice a day to best prevent plaque.  Unfortunately, when it comes to medical devices or any surface (particularly a porous or textured surface) in a medical treatment facility (such as lead wearables), biofilms can form once the surface is exposed to organic matter such as blood.  Now with the mental picture of layers of bacteria (such as plaque) on surfaces in medical treatment facilities, consider that some high-touch surfaces, such as radiological shields and aprons have not been properly cleaned for years (if ever!)

Elbow Grease Helps Break Up Biofilms

Biofilms are so tolerant of antimicrobials and antiseptics, that even the CDC positions the best way to remove a biofilm is to disrupt it physically, and they have included the ‘use of friction’ in their definition for proper cleaning.  Studies have been done that show that physically disrupting the biofilm by using friction is the primary means for destruction of the layers and thus removal of the biofilm.  (In the example of dental plaque, this would be equivalent of one going to the dentist and having them scrape the teeth in order to remove the plaque.)  The procedural process and outcomes are different when looking at the process of “cleaning” and “sanitizing” and it takes both of these separate processes to eradicate biofilms from porous, high touch surfaces. The surface on a lead wearable first needs to be cleaned before it can then be sanitized.

  • Cleaning – According to the CDC, cleaning entails the use of EPA registered products, coupled with the use of friction to physically remove dirt, microorganisms and bioburden and then removing/rinsing them away from the surface. Though a vast majority of the bioburden is removed during this process, the cleaning process does not always remove 100% of all bioburden & microorganisms.
  • Sanitizing – This process then “inactivates” 99.9% of all remaining microorganisms on environmental surfaces if allowed to sit visibly wet or “dwell” on the surface for the recommended amount of “dwell time” as per manufacturer instructions and guidelines.

Cleaning and Sanitizing really can’t be done in one-step, let alone with just a wipe. When you go to the dentist, the first step in the process is to scrape the plaque from the teeth before they are polished, just like your car needs to be adequately washed and dried, before it can be then waxed. Cleaning and sanitizing of a neglected surface such as a lead apron cannot be accomplished in one step either. In an effort to address such biofilms “head on” X-Ray apron servicing companies, such as Radiological Care Services (IN) are implementing multi-step, cleaning and sanitization programs for X-ray aprons and lead wearables. These programs are built in accordance with governing bodies, such as the CDC, JCAHO, AORN and HFAP, which position that surfaces should first be cleaned, before attempting to sanitize or disinfect them.

Stay Tuned For The Next Post

Stay tuned for the next follow up blog post, as we look specifically at what policies, regulations and expectations these governing bodies have of high touch surfaces, such as X-ray aprons and lead wearables. Between now and then, go brush your teeth and think about the layers of bacteria building up on lead wearables and aprons as they continue to invite bacteria to the biofilm party!

About The Author:

Kathleen R. Jones received her BS from Purdue University (West Lafayette) in Biology specializing in Genetics and Microbiology.   After working for five years in Quality Control she then completed her MS at Purdue University in Indianapolis.  Her growing interest in Infectious Diseases lead her to the Uniformed Services University of the Health Sciences where she obtained a Doctorate in Emerging Infectious Diseases.  Kathleen has a passion for progressive sciences and initiatives, and employs her keen understanding of the biofilm formation and elimination processes into her research and work.

Evaluating Microorganism Levels On X-Ray Aprons And Lead Wearables: The Science Of ATP Testing

How Have Microorganisms and Bioburden Been Measured?

In the previous blog post regarding X-Ray lead aprons, we explored the history of healthcare associated infections or HAIs, and how transmission risks are posed to patients and staff via contaminated “high touch, non-critical surfaces,” including X-Ray aprons and protective lead wearables.  In laying out the content of this blog, I was reminded of the phrases, “things aren’t always as they appear” and “don’t judge a book by its cover.” Is it possible that newer (clean looking) X-Ray aprons can carry a higher level of biological contamination when tested in comparison to older X-Ray aprons (which are dirty looking & smelling)? It is completely possible and plausible due to the concept of bioburden.

What is Bioburden?

Bioburden is defined in numerous medical dictionaries as the number of microorganisms contaminating an object.  So how does one assess for bioburden?  The gold standard for assessing for bacterial/fungal contamination has been to assess for colony forming units or CFUs.  A CFU equals one viable bacterium that has the ability to spread and replicate.

3 Main Ways to Measure CFUs: 

  1. A scientist could dilute the sample and count the bacteria by microscopic examination or through the use of a cell counter.  However, if bacteria are too small or clump together, then this method is problematic.  This method will yield total bacteria counts, both living and dead.
  2. A scientist could use Optical Density (OD) to estimate the number of viable bacteria in a sample.  This is where the scientist measures how cloudy a liquid culture of bacteria is.  While the bacteria are actively growing the liquid culture should continually become more and more cloudy.  Again, this method will yield total bacteria counts, both living and dead.
  3. A scientist could make serial dilutions of a liquid culture and plate out the bacteria in known dilutions until they can count single colonies and extrapolate back to figure out total CFU in a sample. This method only yields viable bacteria totals.

4 Challenges Associated with Bioburden Assessment

Assessing for bioburden (microorganisms) by calculating CFUs is not as easy or straight forward as one might imagine.

  1. The first challenge posed is that one needs to have a lab in which to grow bacteria, and depending on the bacteria one is dealing with there are different governmental regulations to follow.
  2. The second challenge presented is that of time, one needs to have the time and equipment to properly grow the bacteria/fungus.  Different species of bacteria or fungus grow at different rates, for example, culturing of bacteria on plates can take anywhere from overnight to multiple days.
  3. A third and very important challenge is posed by the bacteria and fungus themselves.  They are similar to people in the fact that not all of them grow and thrive under the same conditions.  In lab work, if only one kind of food source is used, one will only be able to assess for bacteria that grow on that particular food source.
  4. Finally, one needs to have a trained technician who knows how to assess which bacteria to grow under the correct conditions and then also how to properly count the bacteria.

While assessing for CFUs has traditionally been viewed as the gold standard for assessing bioburden, and it is vitally important for various microbial studies, it is not a good way to assess bioburden in real time.  It can be complicated.

What is ATP and How is it Evaluated?

What if there was an easier way to determine surface levels of biological contamination?

What if there was an easier way to assess for a molecule that is found only in living cells, both bacterial and human living cells?

There IS an easier way to evaluate for this molecule in real time (by using a simple swab and handheld reader), and it can be used by any hospital staff member as a surrogate for such complicated CFU work.  Let me introduce you to the molecule known as the “molecular workhorse,” called adenosine triphosphate (ATP).

Adenosine Triphosphate (ATP)

ATP is an energy molecule utilized by cells. It is present in humans, animals, plants and microbial cells.  ATP levels rise as a cell is undergoing apoptosis (programed cell death), but is generally consider to be completely degraded within 30 minutes of cell death (1).  This makes ATP a useful marker for the presence of unwanted biological contamination, including organisms that can cause infection and disease.

Okay – Get to the Point!

An increase in biological cells on a surface results in an increase in the amount of ATP present on that surface, thus making ATP an effective marker for the assessment of the hygienic status of an environmental surface. Simply stated, the amount of ATP present on a testing swab is a quantitative measurement of the cleanliness of the surface tested! In fact, ATP cell viability assays were determined to be the fastest, most sensitive, and least prone to artifacts, partially due to a lack of an incubation period (2).  The sensitivity of laboratory cell based ATP cell viability assays can detect fewer than 10 cells per well (2).  This technology has been modified to create a portable, ATP bioluminescence test, using a swab instead of plated cells.  This now allows for a real time assessment of bioburden on site.  These tests have been used to assess bioburden in many healthcare settings, including the ICU (3).  ATP measuring units, called luminometers, are handheld, user friendly, and display the results in seconds. (It doesn’t take a scientist to use an ATP luminometer!) The read out of an ATP bioluminescence test is not in CFUs, but is in relative light units or RLUs.  In the past, some scientists have questioned the validity of using a bioluminescence test instead of assaying for CFU.

Is There a Correlation Between CFUs & RLUs? 

Like most assessments, ATP bioluminescence assays also have limitations, but they are an excellent surrogate that allows the everyday staff member to assess bioburden in real time.  Those new to ATP bioluminescence testing often inquire about a correlation between CFUs and RLUs.  (Most laboratory microbiologists have the capability to perform CFU testing, and are not confined to real time assessment of bioburden.)  The most controlled way to achieve this is to look at different known amounts of CFUs and assess whether or not the RLUs increase accordingly.  That is exactly what Dr. Sciortino’s group did when they assessed three different portable ATP bioluminescence kits for their ability to detect various CFUs of two different HAI relevant bacteria (Staphylococcus aureus and Acinetobacter baumannii) and one strain of fungus (Candida albicans).

What they discovered was there was a linear relationship between bacterial CFUs and RLUs for all three luminescence kits, and for two of the three kits between fungal CFUs and RLUs (1).  Such research validates that the use of ATP luminometers can be used to assess for bioburden on surfaces in real time.  This research, plus Dr. Jaber’s study, in which 25 lead aprons were cultured for CFUs and showed that 21 were colonized with Tinea species (the family of fungus that causes ringworm) and 21 were colonized with Staphylococcus aureus, of which 3 aprons were colonized with MRSA (4), validates the ATP bioluminescence results for X-ray aprons and protective lead wearables.

In fact, these X-ray aprons and protective lead wearables, which are worn throughout many different areas within a healthcare system, including the operating rooms, cath labs, radiology/imaging areas, emergency rooms and beyond are regularly testing with RLU readings in the THOUSANDS to HUNDREDS OF THOUSANDS (5), which is scary. The bottom line is regardless if you are a classically trained microbiologist used to looking at CFUs or a hospital staffer looking at luminometer readouts in RLUs, when surfaces inside an OR or Cath Lab are testing in the hundreds of thousands range, it is a problem!

Is ATP Testing Growing in Use?

Through utilization of ATP luminometer testing systems, companies like Radiological Care Services (Indianapolis) are able to enter a facility’s Cath Lab, OR or Radiology Department and test lead apron inventories on site, providing real time numbers (bioburden levels) in a matter of seconds. An advocate for ATP luminometer testing, Dr. Sciortino even states, “ATP system monitoring may uncover the need for new disinfectant designs that adequately remove hospital surface biofilms, rendering used hospital equipment to its native state whereby a zero reading by ATP monitoring can be achieved” (1).  If you look back at the first blog post, “Contaminated X-Ray Aprons and The Risk of HAIs”, I positioned that “using wipes alone” was insufficient and through the use of ATP testing, Dr. Sciortino could be inferring a similar position.

Looking Ahead…

In the next blog post, we’ll specifically look at the science/methodology behind the use of sanitizing wipes and we’ll further explore the differences between true “cleaning” and “sanitization.” We’ll later examine what the governing bodies, such as AORN, CDC, HFAP and JCAHO state regarding their expectations of such surfaces within healthcare facilities. Understanding the science behind HAIs, testing for biological contaminants on surfaces, biofilms, and the difference between “cleaning” and “sanitization” will help us understand that current healthcare protocols in regards “non-critical, high touch surfaces” need to be changed in order to better protect hospital patients and staff.

About The Author:

Kathleen R. Jones received her BS from Purdue University (West Lafayette) in Biology specializing in Genetics and Microbiology.   After working for five years in Quality Control she then completed her MS at Purdue University in Indianapolis.  Her growing interest in Infectious Diseases lead her to the Uniformed Services University of the Health Sciences where she obtained a Doctorate in Emerging Infectious Diseases.  Kathleen has a passion for progressive sciences and initiatives, and employs her keen understanding of the biofilm formation and elimination processes into her research and work.

Sources:

  1. Sciortino, C. V. and R. A. Giles.  2012. Validation and comparison of three adenosine triphosphate luminometers for monitoring hospital surface sanitization: A Rosetta Stone for adenosine triphosphate testing.  AJIC.  40 (e233-9)
  2. Riss T.L., R.A. Moravec, A. L. Niles, H.A. Benink, T.J. Worzella, L. Minor. Minor, L, editor.  2013,  Cell Vialblity Assays. In: Sittampalam G.S., N.P. Coussens, H. Nelson, et al., editors. Assay Guidance Manual [Internet]. Bethesda (MD): Eli Lilly & Company and the National Center for Advancing Translational Sciences; 2004-. Available from: http://www.ncbi.nlm.nih.gov/books/NBK144065/
  3. Moore, G., D. Smyth, J. Singleton, P. Wilson. 2010. The use of adenosine triphosphate bioluminescence to assess the efficacy of a modified cleaning program implemented within an intensive care setting.  AJIC. 38(8):617-622 DOI: http://dx.doi.org/10.1016/j.ajic.2010.02.011
  4. Jaber, M., M. Harvill, E. Qiao.  2014.  Lead aprons worn by interventional radiologists contain pathogenic organisms including MRSA and tinea species.  Journal of Vascular and Interventional Radiology.  25:3:S99-S100.  DOI: http://dx.doi.org/10.1016/j.jvir.2013.12.279
  5. “Outcomes: What do your numbers look like?” Radiological Care Services. Nov 20, 2014. http://www.radcareservices.com/radiolgical-care-services-outcomes.html

Contaminated X-Ray Aprons And The Risk Of HAIs

Contaminated, Dangerous, and Unacceptable: The Impact of Contaminated X-Ray Aprons and the Risk of Health Care-Associated Infections (HAIs)

Infection Prevention checklists today include many new areas of concern such as contamination in lab coats, neckties, telephones, remote controls, privacy curtains and more. X-ray aprons and protective lead wearables are worn throughout many different areas within a healthcare system, including the operating rooms, cath labs, radiology/imaging areas, emergency rooms and beyond. Clinical studies have proven that X-ray aprons silently carry a number of microorganisms – Dr. Jaber (Wayne State) cultured 25 lead aprons to discover 21 were colonized with Tinea species (the family of fungus that causes ringworm) and 21 were colonized with Staphylococcus aureus, of which 3 aprons were colonized with MRSA (1).  

The Association of periOperative Registered Nurses (AORN) makes cleaning recommendations for items such as kick buckets, stools, patient restraints, keyboards, surgical lights and more; however, lead aprons which are routinely engulfed in sweat, blood, bodily discharge and surgical debris/residue have been consistently overlooked. Healthcare systems can no longer compromise both patient and staff safety through such perilous practices.  (Note – upcoming posts will further explore “current cleaning practices,” as well as cleaning recommendations and guidelines from National Governing Bodies such as the CDC/JCAHO/HFAP and AORN.)

Health Care-Associated Infections

HAIs are the 4th largest killer in the United States, claiming 100,000 American lives each year – more deaths than AIDS, breast cancer and auto accidents combined (2).

Hospitals are meant to be safe havens.  They are meant to be a place of refuge against disease, a place to heal and a place to recover from surgery or injury.  If that is the dream, then the nightmare would be a place in which you end up more ill than you were when you were first admitted!  Unfortunately, that nightmare becomes a reality for many unsuspecting patients and staff members today. One reason for this nightmare is the acquisition of a Health Care Associated-Infection or Hospital Acquired Infection (“nosocomial infection”).

The World Health Organization (WHO) uses a 1995 definition for a Hospital Acquired Infection (HAI):

An infection occurring in a patient in a hospital or other health facility in whom the infection was not present or incubating at the time of admission.  This includes infections acquired in the hospitals but appearing after discharge, and also occupational infections among staff of the facility (3).

HAIs in our Healthcare System

Think about it – it only makes sense that hospital acquired infections would be prevalent in our healthcare systems today.  Hospitals & medical facilities are places that people congregate when they are immunocompromised and/or are sick and in need of some type of care or treatment.

World Health Organization Study

In fact, a WHO study of various hospitals in 14 countries across Europe, Eastern Mediterranean, Southeast Asia and Western Pacific regions in the late 1980s concluded that 8.7% of patients had at least one Hospital Acquired Infection equaling 1.4 million afflicted people at any one time (4-5).

Centers for Disease Control and Prevention Estimate

In the United States alone, the CDC estimates roughly 1.7 million annual hospital-associated infections, from all types of microorganisms including bacteria combined, cause or contribute to 100,000 deaths each year (6). In fact, approximately 1 in 25 hospital patients has a hospital acquired infection at any one time (7). While these statistics are startling and horrifying, sadly they do not paint the complete picture. These statistics are patient specific and do not include the number of healthcare workers and hospital staff who have also acquired Hospital Acquired Infections.

Economic Impact of HAIs

Such infections lead to additional stress, longer hospital stays, lost wages for healthcare providers and higher morbidity and mortality rates overall.  HAIs also have a HUGE economic impact.  In addition to being the 4th largest killer in America, it is estimated Hospital Acquired Infections will cost the healthcare system an additional $30 Billion (2).

Why do HAIs Occur? 

We live in a medically advanced society, so why do Health Care Associated-Infections still run rampant, and what are we doing about them?  That is a good question, but the answer is multifaceted.  The first point to consider is that patients are usually immunocompromised when in need of healthcare services. They are either already ill or they have had a procedure that puts immense stress on their bodies, e.g., a joint replacement, major illness or other surgical procedure or treatment. 

As wonderful as modern medicine is, it is not without risks.  In fact, many diagnostic and/or therapeutic procedures involve the use of a medical device, e.g, catheters, intubation tubing, scopes, etc. These devices and even many “non-critical” surfaces and “high touch objects” such as X-ray aprons and lead wearables can become contaminated when not properly cleaned and sanitized.

Healthcare facilities are a place where sick and immunocompromised patients regularly navigate and patients are often transferred between units/floors.  This allows infectious agents to travel to different areas in a hospital and expose multiple people, including patients, family and staff members.

Infectious Agents

Infectious agents (bacteria, viruses, parasites, and fungi) present their own issues.  There are species that form spores that are resistant to most mechanisms of eradication. Kramer’s group recently performed a meta-analysis of the literature and summarized that most clinically relevant species of viruses could easily survive on dry, inanimate surfaces for between a few HOURS to DAYS and clinically relevant bacterial and fungal species could survive for DAYS to MONTHS (8).  The longer the infectious agent can be found in the environment the greater the chance that it can be passed to a new host.

The Need for New Policies/Protocols

Unfortunately, Health Care-Associated Infections (HAIs) are still a substantial source of morbidity and mortality throughout the healthcare continuum today.  While recent initiatives such as improved hand washing policies have helped that burden, there are additional new policies/protocols with regards to cleaning that need to be implemented in order to address other critical “high touch objects” such as X-ray aprons and lead wearables.

Education and Awareness

Through education and open-mindedness, we can bring awareness to the importance of following the cleaning recommendations of the governing bodies, such as the CDC/JCAHO/AORN and HFAP.  In knowing that infectious agents can still adapt to become drug resistant, antiseptic resistant, and increase their ability to survive in the environment, so, we too must adapt and be open minded to new concepts in our vigilant fight against hospital acquired infections.

Oft-Overlooked: X-Ray Aprons and Lead Wearables

X-ray aprons and lead wearables can no longer be overlooked, and they will need a renewed commitment to servicing. They need to be properly cleaned prior to sanitization efforts, in accordance with the guidelines of the CDC & JCAHO.  In my next blog entry, we’ll dive into the science behind testing X-ray aprons for the presence of microorganisms and examine how these surfaces are measured and evaluated.

SPOILER ALERT – If you think you have an idea of how contaminated such surfaces are inside of our healthcare systems, you will be in for a SURPRISE!

About The Author:

Kathleen R. Jones received her BS from Purdue University (West Lafayette) in Biology specializing in Genetics and Microbiology.   After working for five years in Quality Control she then completed her MS at Purdue University in Indianapolis.  Her growing interest in Infectious Diseases lead her to the Uniformed Services University of the Health Sciences where she obtained a Doctorate in Emerging Infectious Diseases.  Kathleen has a passion for progressive sciences and initiatives, and employs her keen understanding of the biofilm formation and elimination processes into her research and work.

Sources:

  1. Jaber, M., M. Harvill, E. Qiao.  2014.  Lead aprons worn by interventional radiologists contain pathogenic organisms including MRSA and tinea species.  Journal of Vascular and Interventional Radiology.  25:3:S99-S100.  DOI: http://dx.doi.org/10.1016/j.jvir.2013.12.279
  2. “What is RID?” Committee to Reduce Infection Deaths.  n.p.  d.p.  Web.  Nov 7, 2014.  http://www.hospitalinfection.org/objective.shtml
  3. Benenson, AS.  1995.  Control of communicable diseases manual.  16th edition.  Washington, American Public Health Association.
  4. Tikomirov, E.  1987. WHO Programme for the Control of Hospital Infections.  Chemiotherapia. 3:148-151.
  5. Mayon-White, RT, G.  Ducel, T. Kereselidze, E. Tikomirov.  1988.  An internal survey of the prevalence of hospital-acquired infection.  J. Hosp. Infect.  11 (SupplementA): 43-48
  6. Klevens, RM, JR Edwards, CL Richards, TC Horan, RP Gaynes, DA Pollock, DM Cardo.  2007.  Estimating health care-associated infections and deaths in U.S. hospitals, 2002.  Public Health Rep 122:160-166
  7. Magill, SS, JR Edwards, W Bamber, ZG Beldavs, G Dumyati, MA Kainer, R Lynfield, M Maloney, L McAllister-Hollod, J Nadle, SM Ray, DL Thompson, LE Wilson, SK Fridkin.  2014.  Multistate Point-Prevalence Survey of Health Care-Associated Infections.  N Engl J Med 370:1198-1208
  8. Kramer, A., I. Schwebke, and G. Kampf.  2006.  How long do nosocomial pathogens persist on inanimate surfaces? A Systemic Review. BMC Infectious Diseases.  6:130  Doi: 10.1186/1471-2334-6-130

What is FluoroSafety?

Identifying Important Risks Associated with FGI

In 1994 the FDA released a public health advisory warning of the potential for serious radiation-induced skin injuries to patients resulting from fluoroscopically guided interventions (FGI).  In the 20 years since this advisory, there have been hundreds of published cases of skin injury resulting from FGI, and the number is steadily increasing even today.  As the scope of disease that can be diagnosed and treated using FGI increases, so does the complexity of these procedures and the radiation doses to patients, physicians, and staff.  While these procedures provide an incredible benefit to the patient compared to open-surgical alternatives, there are important risks that must be understood by the performing physician.

The Need for Effective Training

In 2010, frustrated by the lack of user-friendly, accessible, and effective training focused on this topic, two diagnostic medical physicists started Fluoroscopic Safety, LLC [http://www.fluorosafety.com]. Understanding the need for a balanced perspective and considering that radiation is not the only risk from FGI, they collaborated with an experienced board certified interventional radiologist well-known for his work in quality improvement.  Because of the multi-disciplinary M.D. and Ph.D. backgrounds of the authors of FluoroSafety courses, we understand that when a physician is performing an FGI, managing radiation dose is not the first thing on his mind.  Instead, practitioners are thinking about the patient-specific technical challenges associated with these procedures.  The training programs from FluoroSafety are developed with this in mind.  While our courses do provide instruction on the fundamental physics of fluoroscopy and radiation biology, we focus on simple methods for managing patient and staff radiation dose.  Using videos and animations, our courses provide an easy to remember and easy to execute set of practices which benefit both the physician and their patients.  This is one of the key features of our courses, designed by physicians and physicists together.

Fluoro CME Training and Education

The educational programs from FluoroSafety also help providers satisfy state regulatory requirements. Through a joint sponsorship with The University of Texas MD Anderson Cancer Center, our courses have been approved for up to 10.5 hours of AMA PRA Category 1 CreditTM.   Our programs meet the training requirements for practitioners who use fluoroscopy in Oregon, California, and Texas.  In addition, board certified providers who complete these courses are eligible to claim self assessment CME (SA-CME), as required for Maintenance of Certification (MOC) by members of the American Board of Medical Specialties (ABMS).

Interactive and Engaging Content

The educational programs from FluoroSafety are tailored to the needs of busy healthcare professionals and feature on-demand Flash-based learning rich in animations and videos.  Our courses also feature optional narration.  Course content can be accessed at the convenience of the physician from any computer, smartphone, or tablet with Internet access.

Meet State Requirements

Whether you are trying to meet state regulatory requirements or are simply interested in improving the care you provide to your patients, FluoroSafety has a course for you.  The most common feedback we have received from physicians who have taken our course is that they were surprised by how much they didn’t know about the safe use of fluoroscopy—you may be surprised too!

FluoroSafety.com

A. Kyle Jones, PhD

Alexander S. Pasciak, PhD

Joseph Steele, MD

Fluoroscopic Safety, LLC

Creating A Patient Safety Program In A Fluoroscopy Practice

Every department performing fluoroscopically-guided procedures should take a few basic steps to ensure patient safety.  These steps are outlined in this article from FluoroSafety and Universal Medical.

Educate fluoroscope operators

Anyone operating a fluoroscope should be trained in basic fluoroscopy physics, basic radiation biology, and radiation safety.  The Basic Training Program from FluoroSafety provides this necessary didactic training for practitioners who perform simple fluoroscopic procedures, and for personnel, including nurses, anesthesia support, and others, who work in a fluoroscopy lab.

Practitioners who frequently perform fluoroscopic procedures or who perform fluoroscopically-guided interventions require training in some additional areas, including advanced fluoroscopy physics, dose monitoring, and optimizing patient dose.  The Advanced Training Program from FluoroSafety provides this training.

Situational awareness

A phrase most often heard on sports broadcasts, situational awareness is critical during fluoroscopic procedures.  Everyone involved in a fluoroscopic procedure should be aware of potentially dangerous situations, and a culture of respect and safety must be in place so anyone feels comfortable speaking up when they see a potentially dangerous situation.  For example, during fluoroscopic procedures performed with a mobile C-arm in the operating theatre, a patient’s arm may be placed dangerously close to the output port of the X-ray tube, especially if the spacer cone has been removed.  The physician is often concentrating on the medical aspects of the procedure, and may not notice that the patient is in danger.  However, a technologist or nurse may notice, and they should immediately notify the physician that the procedural setup requires modification.

Dose monitoring and audits

Every practice using fluoroscopy should be recording dose metrics from procedures and should have a process in place to review these metrics on a regular basis.  Dose metrics can be compared to national averages or other published data to identify targets for practice quality improvement.  Consider the data in the table below.  When performing nephrostomy placements, Facility A has reference air kerma values (Ka,r) that are similar to published national averages.  However, Facility A has air kerma area product (PKA) values that are substantially higher than the national average.  This could indicate that Facility A needs to pay more attention to collimation of the X-ray beam during fluoroscopic procedures.

MetricFacility ANational Average
Reference air kerma (Ka,r)250 mGy245 mGy
Air kerma area product (PKA)90 Gy-cm²49 Gy-cm²

Consent

Practices performing complex fluoroscopically-guided interventions should add a few more elements to their patient safety programs.  These elements and others are discussed in more detail in the Establishing a Patient Safety Program course from FluoroSafety.

Patients who are considering undergoing a potentially high dose fluoroscopic procedure should be explicitly informed of the risk, albeit very small, of a radiation-induced skin reaction.  This is both ethically responsible and documents that the practice informed the patient that a skin reaction was a potential risk.

Notification levels

Notification levels can be considered a particular form of situation awareness.  A notification level is a Ka,r threshold that, when reached, triggers specific actions by the practitioner.  Most importantly, a notification level is an opportunity for the operator to consider the risk/benefit pace of the procedure and to make modifications to the procedure that reduce the rate at which skin dose accumulates.  The table below is an example of notification levels for vascular and interventional radiology procedures.

Ka,r Notification Level (mGy)Suggested Action
2,500Verify Good Practice is being used
5,000 Substantial radiation dose level. Flag patient for follow up. Measure and record patient table height.
7,500Verify Good Practice. Re-evaluate risk/benefit pace of procedure, entering range of potential skin injury.
10,000Verify Good Practice. Re-evaluate risk/benefit pace of procedure. Skin injury more likely.

Follow up of patients experiencing high skin doses

A follow-up protocol should be in place for patients experiencing doses greater than a practice’s Substantial Radiation Dose Level (SRDL).  The National Council on Radiation Protection and Measurement recommends that the SRDL for Ka,r be set at 5 Gy (5,000 mGy). The follow-up protocol may include a 4-week phone or in-person follow-up, and a procedure for intensive management of patients suspected to have a skin reaction.  A procedure for tracking patients undergoing multiple or repeated high dose procedures should also be in place

About The Author:

A. Kyle Jones, PhD, DABR

Co-Founder, Fluoroscopic Safety, LLC

Dr. Kyle Jones earned his B.S. in physics from Furman University and his M.S. and Ph.D. in medical physics from the University of Florida. Dr. Jones is currently employed as a Diagnostic Medical Physicist and Assistant Professor at MD Anderson Cancer Center.

Dr. Jones is board certified in Diagnostic Medical Physics by the American Board of Radiology, is a Licensed Medical Physicist in the state of Texas, and is MQSA qualified. Dr. Jones is active in multiple research endeavors in the fields of radiation safety and diagnostic medical physics, is widely published in high impact journals, and is actively involved in teaching and training medical physics graduate students, medical physics residents, and interventional radiology fellows.

 

 

 

Radioprotective Garments: A Medical Physicist’s Perspective

If you read our previous blog post on ALARA, you learned that the ALARA standard used worldwide for managing dose to radiation workers actually stems from the Linear-No-Threshold (LNT) dose-response model. If the LNT model is correct, risk of deleterious effects like cancer increases linearly with radiation dose, and there is no safe amount of radiation exposure where the increased risk is zero. Because LNT suggests that there is no safe radiation dose, this motivates us to keep both our radiation dose, and the radiation dose that our patients receive very low. One of the most important ways that we, as radiation workers, accomplish ALARA is through the use of radioprotective garments. In this article from FluoroSafety and Universal Medical, several aspects of radioprotective garments will be discussed.

Radioprotective Garments

Today, radioprotective garments come in all shapes and sizes and are made from many different materials. In fact, the use of “lead aprons” to describe these garments is not quite correct, as many garments currently on the market contain no lead. Many different types of garments are used individually or in concert to protect radiation workers, including aprons, thyroid collars, vests, kilts, and protective eyewear. Let’s take a closer look at the difference between lead and lead-alternative protective garments.

Lead Protective Garments

The conventional lead apron is actually made from more than just lead; it is lead powder permanently bonded in a thick rubber or vinyl matrix allowing the apron to be flexible, comfortable, and long-lasting.  The rubber matrix is further protected by a thin vinyl covering which facilitates cleaning, while nylon straps with either Velcro or compression buckles secure it to the wearer. The protection provided by a lead garment may be quoted simply as “0.50-mm lead” or as “0.50-mm lead-equivalent”. These descriptions are interchangeable for lead garments.

A typical 0.50-mm lead apron will transmit approximately 2% of a scattered fluoroscopic X-ray beam.

Lead-Alternative Protective Garments

The product lines of most vendors now include lead-alternative radioprotective garments. Such garments may be lead-free or lead-composite. Lead-free garments use metals such as tungsten, tin, antimony, and bismuth in place of lead, while lead-alternative garments still incorporate some lead along with these other metals. The construction of lead-alternative garments is nearly identical to that of lead garments, except that metal powders other than lead are included in the rubber matrix that comprises the protective layer of the garment.

Advantages of Lead-Free Garments

Lead-free garments have two advantages over lead garments. First, lead-free garments are environmentally friendly and non-hazardous. Hospitals that replace a large number of protective garments each year may see a small cost savings because disposal of worn out lead-free garments can be handled through a conventional waste stream, while lead or lead-composite garments must be handled as hazardous waste. The second potential advantage of lead-free garments is the possibility that, by optimizing the mix of metals used in the garment, a garment that has the same performance as lead, while being lighter weight, may result. This is possible because the alternative metals used have strong absorption k-edges that closely match the energies of scattered fluoroscopic X-rays. Over a narrow range of energies, these metals attenuate radiation as well as or better than lead while being less dense, and therefore lower weight than lead. Manufacturers of such garments often advertise them as being “lighter than lead” while providing the same protection.

Determining Lead Equivalence

These are difficult claims to evaluate. Because lead-free garments do not use lead, determining the lead equivalence of such a garment is an extremely challenging problem. Recall from the last paragraph that the alternative metals absorb radiation as efficiently as lead only over a very narrow range of energies. This is one reason that a number of different metals are used, to spread this range out as much as possible. This also means that transmission of a lead-free garment depends very strongly on X-ray energy¹. Therefore, the specification of the “lead-equivalence” of such a garment at a single X-ray energy is not a complete characterization of its protective value.

Radioprotective garments typically provide the full rated protection at the front of the garment. Aprons have a single full-thickness layer while a skirt will overlap to provide the full rated thickness in the front. Most garments provide less than the full rated protection at the back (e.g., 0.25-mm), as most medical radiation workers face the source of radiation. This is an important consideration for fellows or other radiation workers who spend large amounts of time with their back facing the patient – such workers may consider purchasing a garment with at least 0.35-mm protection in the back.

Until recently, many state regulations required that personnel working around fluoroscopes wear protective garments of at least 0.50-mm lead equivalence. However, recently the National Council on Radiation Protection and Measurements, considering the tradeoff between orthopedic strain and radiation protection, suggested that 0.35 mm lead-equivalent garments are sufficient for most medical radiation workers², and state regulations are being updated to reflect this new guidance. While a typical 0.50-mm lead apron transmits approximately 2% of a typical scattered fluoroscopic X-ray beam, a 0.35-mm lead apron transmits approximately 5%. For comparison, the transmission of 0.50-mm lead-free protective garments typically ranges from 4-6%.

Lead or Lead-Free?

If you are considering changing from a lead to a lead-free garment, or from a nominal 0.50-mm garment to a nominal 0.35-mm garment, the best way to proceed is to ask your radiation safety officer or medical physicist to switch you to an EDE1 radiation monitor wear method. Using the EDE1 wear method, you will be supplied with 2 dosimeters, one worn at the collar level outside your protective garment and one at the waist level under your protective garment. This wear method allows a direct evaluation of the protective value of your new garment for your specific work environment. More details on the EDE1 wear method are available in the Advanced Training Program from FluoroSafety.

A word on weight

While it is possible that lead-free or lead-alternative garments can provide adequate protection at a reduced weight, the most important garment parameter relating to operator comfort is how well it fits. For individuals who wear protective garments every day, a custom fitted vest and kilt combination garment will result in the least orthopedic strain. After due consideration is given to the fit of the garment, the required protective value and weight of different garment options can be considered.

About The Authors:

A. Kyle Jones, PhD and Alexander S. Pasciak, PhD

Founders, Fluoroscopic Safety, LLC

Dr. Kyle Jones earned his B.S. in physics from Furman University and his M.S. and Ph.D. in medical physics from the University of Florida. Dr. Jones is currently employed as a Diagnostic Medical Physicist and Assistant Professor at MD Anderson Cancer Center.

Dr. Jones is board certified in Diagnostic Medical Physics by the American Board of Radiology, is a Licensed Medical Physicist in the state of Texas, and is MQSA qualified. Dr. Jones is active in multiple research endeavors in the fields of radiation safety and diagnostic medical physics, is widely published in high impact journals, and is actively involved in teaching and training medical physics graduate students, medical physics residents, and interventional radiology fellows.

Dr. Alexander Pasciak earned his B.S. in electrical engineering from the University of Washington and his M.Sc. in health physics and Ph.D. in nuclear engineering from Texas A&M University. Dr. Pasciak completed a two-year diagnostic medical physics residency program at MD Anderson Cancer Center in 2009.  For the past five years, Dr. Pasciak has worked as Diagnostic Medical Physicist at the University of Tennessee in Knoxville where he carries the rank of Associate Professor of Radiology.

Sources:


1. A.K. Jones, L.K. Wagner, “On the (f)utility of measuring the lead equivalence of protective garments,” Med Phys 40, 063902 (2013).

http://www.ncbi.nlm.nih.gov/pubmed/23718618

2. National Council on Radiation Protection and Measurements, Radiation dose management for fluoroscopically-guided interventional medical procedures. NCRP Report 168, (NCRP, Bethesda, MD, 2011).

http://www.ncrponline.org/Publications/Press_Releases/168press.html

What Is ALARA?

What is ALARA?

As Low As Reasonably Achievable (ALARA) is a buzzword commonly used in medical disciplines utilizing ionizing radiation for the diagnosis and treatment of disease. It is a phrase that should be considered whenever a patient, healthcare professional or a physician is in a situation where they might be exposed to radiation.  However, what does ALARA really mean in this context, where does it come from, and why is it used?  These questions will be addressed in this article from FluoroSafety and Universal Medical.

It’s all based on the LNT model

The linear-no-threshold (LNT) dose-response model describes the risk of stochastic effects following exposure to ionizing radiation, as a function of dose.  This model is based on available scientific data* from large exposed populations, such as Japanese atomic bomb survivors and is widely accepted by regulatory agencies and governments.  If the LNT model is correct, risk increases linearly with radiation dose, and there is no safe amount of radiation exposure where the increased risk is zero.  Because LNT suggests that there is no safe radiation dose, this motivates us to keep both our radiation dose, and the radiation dose that our patients receive very low.   More details on the LNT are available in the Advanced Training Program from FluoroSafety.

What is reasonable?

The use of ionizing radiation is necessary in many medical disciplines and while the LNT tells us that there is no safe level of radiation, we also understand that there are many cases where radiation must be used.  For example, before X-rays and CT scans, exploratory surgery was often utilized to diagnose unknown medical conditions.  Certainly, no patient would choose to receive exploratory surgery instead of a CT scan because they were concerned about radiation risk!  These risks must be put into perspective and the benefit weighed against the risk—for both patients and medical professionals who work around radiation.

For patients, the benefit of medical exposure to diagnose and treat disease is clear.  However, just because the patient receives a well-defined benefit, does not mean that radiation can be used indiscriminately.  The smallest amount of radiation that will allow the physician to diagnose or treat the suspected condition should be used—in other words, doses should be kept ALARA.  ALARA in diagnostic imaging may be as simple as using the lowest possible CT, X-ray or fluoroscopic technique factors.  It may also include protection devices such as lead aprons or gonadal shields to protect organs that do not need to be imaged.   Newer protection devices such as bismuth breast and eye shields can be useful for certain CT exams and can reduce dose to these sensitive tissues.

In occupationally exposed individuals, the benefit is entirely that of gainful employment.  There is no potential health benefit like there is for a patient receiving a chest X-ray to diagnose disease; therefore, risk/benefit must be adjusted accordingly.  The federal government strictly enforces dose limits for the occupationally exposed to protect this population which does not receive a well-defined benefit for their radiation exposure.  In practice, very few occupationally exposed individuals approach the federal dose limits, primarily due to their job function.  A CT technologist for instance, leaves the scanner room prior to starting the scan.  Lead shielding in the walls keeps the technologist’s dose ALARA.

However, technologists, nurses and physicians involved in fluoroscopic procedures often do not have the luxury of leaving the examination room while X-rays are being produced.  For these individuals, doses may be maintained ALARA by following the three cardinal rules of radiation protection, which are also discussed in detail in the Advanced Training Program from FluoroSafety.

Time, Distance and Shielding

In fluoroscopic procedures, occupational dose is proportional to the amount of time spent in the room when X-rays are being produced.  Staff dose can be reduced by keeping non-essential personnel out or by stepping outside when performing digital acquisition imaging or rotational CT angiography.  Power injectors are necessary in these cases and allow for both a reduction in staff dose as well is improved vascular contrast.

Another key component of keeping occupational doses ALARA is distance.   Often times the scattered radiation coming from a patient in a fluoroscopic, CT or X-ray procedure can be approximated as a point source; to this end the inverse square law applies.  Therefore, if one doubles their distance away from the source of radiation, the dose to that individual is decreased by a factor of four.  In fluoroscopy or CT procedures, it is often the case that taking one step back away from the patient will cut your dose in half.  Ancillary personnel who do not need to be near the patient can minimize their dose by maximizing their distance.

The final way to maintain doses ALARA is to use shielding whenever possible.  Personnel protective equipment consisting of lead or lead-free garments an integral component of proper radiation safety practice when working near fluoroscopy, CT or X-ray procedures.  Individuals in the room during fluoroscopy procedures should also wear protective thyroid collars and lead glasses to protect these sensitive organs.  For interventional fluoroscopy procedures, some operators find that sterile radiation reduction drapes can decrease their exposure to radiation.  Rolling and hanging glass shields provide superior protection compared to radiation reduction garments and should always be worn when commensurate with the goals of the procedure.

About the Author: 

Alexander S. Pasciak, PhD, DABR
Co-Founder, Fluoroscopic Safety, LLC
www.FluoroSafety.com
 
 Dr. Alexander Pasciak earned his B.S. in electrical engineering from the University of Washington and his M.Sc. in health physics and Ph.D. in nuclear engineering from Texas A&M University. Dr. Pasciak completed a two-year diagnostic medical physics residency program at MD Anderson Cancer Center in 2009.  For the past five years, Dr. Pasciak has worked as Diagnostic Medical Physicist at the University of Tennessee in Knoxville where he carries the rank of Associate Professor of Radiology.
 

Sources: 

*National Research Council. Health risks from exposure to low levels of ionizing radiation: BEIR VII—Phase 2. National Academies Press; Washington, DC: 2005.