Limited Exposure
By Jeannette Sabatini
Radiology Today
Vol. 20 No. 2 P. 24

Minimizing your staff's radiation exposure requires planning.

Radiology workers are at risk of radiation exposure with each image they take, and that risk is increasing for those working in specific areas of radiology, namely fluoroscopy and nuclear medicine, says Cari Kitahara, PhD, an investigator within the National Cancer Institute's radiation epidemiology branch, in the division of cancer epidemiology and genetics. These professionals are filling an increased demand, according to Kitahara, who is reviewing background information provided by professionals in these fields to help determine the accuracy of current dose limits.

"For these workers, especially those performing interventional procedures, there is wide variability in the level of exposure received that reflects the potential for considerable improvement through more effective radiation protection equipment and practices and more rigorous radiation safety training," Kitahara says.

That's good advice for anyone working in radiology. But what other steps can help a radiation safety program reduce staff dose exposure? Radiology Today speaks with some experts to find out.

Have a purposeful occupational dosimetry program.
At Duke University Medical Center in Durham, North Carolina, the radiation safety division's goal is to maintain the occupational exposure for most workers below 10% of the occupational limits, explains Robert Reiman, MSPH, MD, DABNM, the associate professor of radiology in the radiation safety division. An occupational dosimetry program is fundamental to reaching that goal.

"A robust occupational dosimetry program helps maintain ALARA," Reiman says. "The key component to a dosimetry program is the personal dosimeter."

One of the newer types of personal dosimetry badges is a digital on-demand dosimeter that allows wearers to check their dose at any time, according to Melody Pierson, RT(R), CRA, manager of imaging services at UCHealth Greeley Hospital in Greeley, Colorado. Speaking from her experience setting up the radiology department as manager of imaging services at UCHealth Longs Peak Hospital in Longmont, Colorado, she recommends dosimeters that allow users to get daily or cumulative readings on demand using an app downloaded on their smartphone or mobile device. Dose readings can also be wirelessly processed and transmitted using an onsite badge reader and accessed online via a computer. Dose is monitored on a monthly basis at Longs Peak Hospital, and individuals are alerted when dose levels are high. The radiation safety officer reserves the right to temporarily restrict a staff member's work with fluoroscopy if dose levels are too high.

"With immediate, on-demand access to current dose data comes the opportunity to alter behavior and mitigate exposure risks—enabling an unprecedented level of administrative control and safety for our staff," Pierson says.

At Longs Peak Hospital, nuclear medicine technologists wear a radiation monitoring badge as well as a ring dosimeter that monitors the dose exposure to their skin, since these professionals use their hands to work with radioisotopes, she explains. Ring dosimeters are sent to the manufacturer for readings on a monthly or quarterly basis.

To monitor surfaces within nuclear medicine, the staff at Duke routinely use Geiger-Mueller detectors to detect any residual contamination at the end of the day and after therapeutic administrations of iodine-131 or lutetium-177.

"The Radiation Safety Division assists them in ensuring that facility surfaces are free of contamination and all employees, monitored or not, do not ingest radioactive material," Reiman explains. "Thyroid probes are used to ensure that undetected ingestion of iodine-131 does not occur for our nuclear medicine technologists and radiopharmacy staff."

Reward staff for timely dosimetry badge return.
It's challenging to get staff to turn in traditional film dosimetry badges. "We expend a lot of effort to get our monitored employees, which is more than 2,000, to wear the monitors properly and to return them for analysis in a timely manner," Reiman notes. "A sound educational program for dosimeter wearers is a must. We require our personnel to complete an online training module annually and work with our dosimetry vendor to identify people who have unusually high exposures."

Philip Campbell, assistant director/radiation safety officer in the environmental health and safety department at the University of Washington in Seattle, which includes the University of Washington Medical Center, has the same challenge. To help meet it, the medical center's radiology department is trying an incentives program; it has been more successful than charging staffers for being late, he says.

Provide up-to-date personal protective equipment.
Radiology staff throughout Duke University's Health System also employ personal protective equipment such as X-ray shielding aprons, thyroid shields, mitts, and leaded eyewear. Pierson knows firsthand the importance of wearing protective equipment, especially leaded eyewear. Although protective equipment is now in use at most facilities, Pierson says, in the early years of her career, radiation education and the connection between X-rays and cataracts or other cancer-related diseases were not well known. A few years back, an eye doctor told the 50-plus-year-old that she had an early cataract. When she told him she had been a radiology tech for 30 years, he said, "That's why you have it."

Norman J. Kleiman, PhD, who works in the Eye Radiation & Environmental Research Laboratory at Mailman School of Public Health at Columbia University in New York, explains, "The longer amount of time you've been practicing interventional medicine, the more likely you are to have changes in your lens associated with radiation exposure. And the more likely you are to have progression to radiation cataracts that impact vision."

Encourage personal accountability.
Staffers have a personal responsibility to protect themselves. "Put everything that you learned in your schooling to work to protect yourself," Pierson says.

Kleiman reminds professionals to take advantage of improvements in technology. "The machines are providing better images with lower exposures. If you are an interventional radiologist, take your foot off the [fluoroscopy] pedal if you don't need it."

"The three concepts we tell staffers, to keep their dose as low as possible, is to minimize your time, maximize your distance, and maximize the shield you have available," Campbell says.

Still, some physicians have higher dose levels because they can't help but put the needs of the patient ahead of their own, Campbell notes. "The physicians justify the dose they are getting for the good of the patient. There is really a balance," he says, emphasizing that the physicians at his facility are still not exceeding regulatory limits for occupational exposure despite making the choice to push the pedal. "As part of the ALARA program, their doses are constantly being evaluated," he adds.

Kleiman, who is also the director of Mailman's MS degree programs in radiological sciences and toxicology within the department of environmental health sciences, wonders why doctors would take a risk with their eyesight. Some interventional radiologists think nothing of being diagnosed with a cataract, as long as the eye doctor tells them they have 20/20 vision, he says. "But, looking at an eye chart in a doctor's brightly lit office is a different occupational scenario than what an interventional radiologist does. They do their work in a dark room looking at a fluoro screen, where they need good resolution and good contrast sensitivity under low light conditions. That is a whole other aspect of vision."

Others don't realize the significant morbidity associated with cataract surgery, Kleiman says. And that morbidity can be subtle. "Some of the older doctors are very pleased because they can see better after cataract surgery, yet their vision is not 100% in terms of glare, flare, good night vision, and subtle decreases in contrast sensitivity, which are important for visualizing fluoro screens," he says.

Some professionals just don't like to wear the glasses, yet current selections weigh less and cost less. Kleiman recommends eyewear that wraps around on the side to protect the temple area. "That's because we think a lot of the scattered dose is coming from the side, not on face," he says.

Fortunately, most X-ray users will never exceed the certain threshold that would result in cataracts, Reiman adds. Yet, he says, some might.

Maintain inventory and assess gear and equipment.
Duke has a focused program to ensure the integrity of the more than 3,500 radiation safety items in its inventory. "This includes maintaining an inventory and auditing the items by local contacts on an annual basis, which is a Joint Commission expectation," Reiman explains. "We employ a web-based inventory system that our contacts 'in the field' can use to maintain their inventory and record the results of their annual inspections."

Radiation safety also maintains an online inventory of all the radiation-producing machines, Reiman adds. "Each machine is checked annually to ensure that it is still present and to see if exchanges of controls and tubes has occurred," he notes. "We also ensure that each piece of equipment is properly registered with the state of North Carolina and that the documentation required by state inspectors is available for audit."

Apply best practices.
Best practices also help keep dose levels as low as reasonably possible. To assure best practices at Duke, the radiation safety division works closely with its clinical imaging physics group and the compliance office. "We also have an active Medical Center Radiation Safety Committee," Reiman says. In addition, facilities should make sure to follow regulations and get certified by the American Board of Radiology, he suggests.

Remember personnel who use radiation outside of the department.
A good radiation safety program focuses on all staff who use radiation, such as vascular surgery, endoscopy, neurosurgery, and orthopedic surgery, Reiman explains. Duke's program also works closely with the breast imaging service, the breast surgery service, and surgical pathology, particularly to assure the safety of radioactive seed localization of nonpalpable breast lesions.

"We supply training and education to nursing and ancillary staff and anyone else in the medical center with radiation exposure who needs it," he says. "Our staff participates in the formal education of radiology residents and teaches in the Duke Medical Physics Graduate Program to ensure that radiation protection principles and operational practices are passed down to the next generation of practitioners."

Keep in mind the principles of justification and optimization.

Staff members also reduce their risk when they know when to perform an exam and when not to, Reiman says. "'No unnecessary exposure to ionizing radiation' means, if an exam isn't necessary, don't do it. It's the principle of justification," he notes. "The principle of optimization is, if an exam or treatment is necessary, it should be done with the lowest dose to the patient that is consistent with a good diagnostic or therapeutic outcome."

— Jeannette Sabatini is a freelance writer based in Malvern, Pennsylvania.