By Keith Loria
Vol. 14 No. 8 P. 16
Patients have been the focus of recent dose-reduction efforts. That’s good, but many providers need better methods to measure and reduce their own radiation exposure.
With all the recent attention on radiation dose reduction, surprisingly little of it has been focused on the interventional providers who face exposure nearly every working day. Few published studies have examined physicians’ and other workers’ exposure and the health risks it presents.
“Although some research has been done pertaining to operator radiation exposure, data in this particular area are somewhat scarce,” says Boris Nikolic, MD, MBA, FSIR, chief of vascular and interventional radiology at Albany Stratton VA Medical Center in Albany, New York. “The Society of Interventional Radiology [SIR] is helping to address this deficit. In one instance, the society is developing a study where a large cohort of interventional radiologists undergoes an eye examination to detect radiation-induced cataracts. Individual eye exam findings will then be correlated with the cumulative radiation dose record of each operator.”
While a certain level of operator radiation exposure is unavoidable, that exposure is different from the radiation exposure patients experience. Patients usually receive a limited number of acute radiation exposures, whereas operators have a more continuous low-dose type of exposure.
“Exposure profiles and radiation risk distribution are likely different between patients and operators. It’s critical to investigate and attempt to quantify any potential risks that may be associated with long-term use of X-ray–guided interventions to interventional operators,” Nikolic says. “Protecting the interventional operator will, in the long run, also benefit the patient as being a guaranteed recipient of high-quality, low-risk, minimally invasive X-ray–guided interventional care.”
Several companies have developed different approaches to addressing this problem, and this article discusses three of them: Unfors RaySafe’s i2 monitoring system, CFI Medical Solutions’ ZeroGravity system, and Philips Healthcare’s DoseWise system.
According to Kevin McMahon, president and general manager of Unfors RaySafe, the biggest challenge with radiation protection is that radiation cannot be detected by human senses. Medical workers rely on thermoluminescent dosimeter badges to measure exposure and confirm it’s within safe levels. However, programs that rely on passive dosimetry have the following two pitfalls:
• Badge feedback can come weeks after exposure, so protective changes often occur after numerous exposures.
• Radiation safety programs typically provide feedback only if an internal dose limit has exceeded safe levels. If exposure is below a defined limit, a provider may not be alerted to exposure at all.
RaySafe’s approach is to make radiation “visible” by using a real-time dose-monitoring dosimeter that sends dose and dose-rate data to a monitor that can be viewed during a procedure. This enables staff to “see” the radiation environment in which they are standing and the rate at which they’re being exposed to radiation, allowing them to take action to reduce their exposure by increasing shielding or changing their position in the room.
“We have seen the RaySafe i2 and the [Philips] DoseAware real-time dose-monitoring systems in action. They result in increased awareness of radiation and provide the ability to avoid radiation and lower your dose,” McMahon says. (Philips rebrands RaySafe badges and monitors, calling it DoseAware, as part of its DoseWise system.) “The real-time dose-monitoring solutions provide the ability to see your radiation exposure as you are receiving it, so you can immediately react and lower it. This realization often results in better utilization of other protective approaches, such as lead shielding, goggles, etc.”
McMahon says small changes can make a large difference. In fact, the University of Rochester Medical Center in New York has reduced physician and staff population dose to meet the International Commission on Radiation Protection 2007 recommendations (ICRP-103). Prior to real-time dose monitoring, this was thought to be impossible.
“Radiation safety programs that rely on passive dosimetry have relegated ALARA to telling workers to be mindful of where they stand during procedures as part of annual training,” McMahon says. “These workers have no way of knowing if what they are doing is effective until it is too late. In addition, as interventions move away from radiology to cardiology, neuro, emergency, and the OR, staff are often less trained about how to protect themselves from radiation.”
Real-time dose monitoring can help to lower patient dose as well. Studies have suggested that because of increased awareness and behavior change, physicians use less radiation during procedures. They are much more cognizant of beam-on time, thereby reducing the amount of radiation exposure.
Dominic Siewko, senior manager of health and product safety for Phillips Healthcare, says providers and managers need to be aware of the potential risks of radiation exposure and take steps to stay within safer limits. He recommends thinking about the following questions:
• What are my radiation exposure readings and how do they compare with my colleagues in the industry and the standards?
• Can I change my workflow to reduce my radiation exposure?
• Do I have real-time insight about my radiation exposure?
• Do I have the right protective equipment?
• Do I use the radiation equipment in the best possible way to minimize radiation?
On the dose-monitoring side, Philips has an agreement with RaySafe to jointly develop real-time monitoring equipment, which Philips markets as DoseAware. The other pieces of the protection puzzle, for both patients and providers, are software and hardware that reduce the amount of radiation used to acquire images.
Control Dose Delivered
“Philips has a companywide focus on low dose. Managing radiation dose exposure while providing high image quality for clinician confidence is one way to support this charge,” Siewko says. “Philips has a specific program called DoseWise focused on ensuring optimal image quality while protecting people in X-ray environments. It is based on our ALARA principle. It’s a philosophy that is active in every level of product design, and it includes creative thinking in three areas: X-ray beam management, less radiation time, and greater dose awareness.”
According to Siewko, several innovations have been implemented with the Philips C-arm X-ray system, such as its patented grid-switched fluoroscopy, beam-filtering optimization, kilovolt/milliampere regulation curve, image-intensifier entrance exposure rate, and automatic dose-rate control. “A unique feature in the Philips system is the patient zone system. Dependent on the rotation angle of the C-arm, radiation exposure is measured over 10 zones,” he notes. “When working in a specific zone, a ‘speedometer’ shows how much time of radiation is left before the limit of radiation exposure under that C-arm angle is reached. Based on this information, the operator can make good decisions on whether to change the C-arm orientation during the case in order to prevent harm to the patient.”
Different C-arm manufacturers offer their own tools for reducing the dose required to acquire images. Philips combines its C-arms with the DoseAware real-time monitoring.
CFI president Mike Czop says there’s a growing body of clinical evidence suggesting occupational radiation exposure contributes to increased incidences of left-side brain tumors, cataracts, and thyroid and other cancers in interventionalists. The heavy leaded apparel to protect clinicians from radiation can cause its own problem.
“Until now, the radiation protection options have been limited to heavy lead apparel, which creates a variety of orthopedic problems in the form of chronic neck, back, and joint pain. Any of these issues alone can be debilitating and even career ending,” Czop says. “The biggest challenge is providing more radiation protection for the user without asking the body to bear the burden of the heavier weight required for increased protection and to do so in an unrestrictive manner that won’t negatively affect clinical procedure workflows.”
More Shielding, Less Burden
The company’s approach to the problem is increasing the level of radiation protection and reducing the orthopedic risks. With the ZeroGravity Radiation Protection System, interventionalists work behind a lead body shield with shoulder flaps and a lead face shield suspended from an overhead arm. A custom-fit sterile drape provides contamination control. The user wears a lightweight, breathable mesh vest under his or her gown that connects to the sterile draped ZeroGravity shield.
“Once connected to the ZeroGravity, the doctor can move easily through the operating area with radiation protection from the tibia to the top of their head,” Czop says. “ZeroGravity offers users radiation protection over a greater body area than standard lead and does it in a way that sustains doctors’ energy and physical comfort throughout their work days, home lives, and careers. Additionally, ZeroGravity provides the flexibility for use in a variety of procedures. Other, non–weight-bearing approaches impose procedural limitations or introduce ergonomic challenges to effective user positioning.”
The system also includes a refined face shield to provide easy monitor viewing and clear acoustics. CFI offers the system with various ceiling-mount configurations to integrate with congested cath lab ceilings. The sterile draping has been refined to provide a contoured fit with easy application.
In the Field
It was only two years ago when Torrance Memorial Medical Center foundation president and diagnostic radiologist Richard Hoffman, MD, succumbed to leukemia. Having spent nearly four decades working in the field, many believe his exposure to radiation early in his career played a role in his death.
“For us, the problem is very personal because of what happened. At the time [Hoffman] was starting, the control of radiation protection wasn’t very good,” says George J. So, MD, the hospital’s radiology department chief. “We should all be very concerned because the problem we are facing now is that the procedures have become more complicated and take more time.” Torrance currently uses both ZeroGravity and DoseAware.
In his own practice, Nikolic strives to increasingly use ultrasonography for image-guided procedures and minimize personal radiation risk.
“Some operators I know have adopted new radiation protection measures and tools into their respective practices. Sometimes, scientific validation of these tools is lacking or incomplete,” Nikolic says. “Among the many devices that have been introduced to the market over the last few years, such as on-site radiation exposure measurement tools, analytic radiation exposure software, leaded gloves, leaded towels, additional leaded aprons, and so forth, some have disappeared and most others are only used sporadically.”
He added that many investigators consider performing original peer-reviewable research on radiation protection unexciting, yet such research’s practical value is considerable.
RaySafe is working to integrate staff dose data into cloud-based software, along with the patient dose and equipment data, so all dose-data aggregation can be accessed in one place. Also, radiation safety officers will be able to truly understand the radiological environment and be proactive in their dose-reduction efforts for both staff and patients.
The best approach for radiation protection is focusing on the patient, since interventionalists’ exposure reflects patient exposure, according to James Spies, MD, MPH, FSIR, president-elect of SIR and a professor and the chair of MedStar Georgetown University Hospital’s department of radiology. He notes that a big challenge is convincing young interventionalists that they’re not invincible. “We constantly reinforce with the young trainees that they are not invulnerable, and they need to use proper shielding,” he says. “We have an aggressive safety program here, and they come out and talk to the group. We focus on appropriate shielding, use of freestanding barriers, ceiling-suspended systems, and trying to get people to adapt to wearing eye protection all the time.”
Nikolic has seen research efforts aimed at improving direct operator shielding, such as the development of new types of thyroid shields that better attenuate radiation and result in less gland absorption. “It seems likely that effectiveness of shielding equipment overall will continuously be worked on and improved,” he says. “There seems to be a trend toward tighter regulation, for instance, as recently passed in the state of Texas and triggered by recently publicized adverse radiation events, or by the trend toward legislatively required enhancement of operator education, as in the commonwealth of Massachusetts.”
So sees a day when robotic interventional radiology becomes the norm, while Czop believes that administrative and regulatory acknowledgement of occupational risks and the inadequacy of traditional methods of protection is critical for facilitating industry change.
“Traditional protection methods are orthopedically inadequate, which can be as damaging as the radiation itself,” he says. “There are better, safer, more physician-friendly alternatives, and they need to be implemented or, as patients, we’re potentially looking at a severely shrinking pool of highly skilled specialists whose talents and knowledge won’t be readily available when we need them. New talent may be very hard to find because there are certainly less risky, more appealing specialties for our medical students.”
— Keith Loria is a freelance writer based in the metro Washington, DC, area.