Dose of Reality
By Dan Harvey
Vol. 21 No. 9 P. 22
Organizations align in the ongoing effort to reduce radiation exposure risks and ensure safety.
In dealing with ongoing radiation risk concerns, organizations such as the ACR, ASRT, and RSNA, and imaging professionals place a strong focus on best practices, communication, and education, both for the patient and imaging personnel. Concerns about radiation safety were forefront in the first decade of the new century, but health care professionals had long been aware of and attentive to radiation risks, eg, the ALARA principle had been adopted for decades. Those concerns are ongoing and seem to be even higher now. Beth Ann Schueler, PhD, FACR, a medical physicist at the Mayo Clinic in Rochester, Minnesota, and cochair of the Image Wisely Initiative, agrees with that observation.
Genesis of the Image Wisely Initiative came about through the ACR’s and RSNA’s Joint Task Force on Adult Radiation Protection, which was formed to address concerns about the increase in public exposure to ionizing radiation that occurs with medical imaging. The Joint Task Force then worked with the American Association of Physicists in Medicine and the ASRT to develop the initiative. Image Wisely’s main thrusts are lowering the amount of radiation in imaging studies and reducing or eliminating repeat or unnecessary procedures.
Schueler cochairs the project with Elliot K. Fishman, MD, FACR, a professor of radiology, surgery, oncology, and urology at Johns Hopkins Medicine in Baltimore, leading a volunteer committee of radiologists, medical physicists, and radiologic technologists who oversee the initiative’s activities. They are also responsible for contributing to the initiative’s educational material and providing information for radiation safety in adult medical imaging.
The initiative’s Image Wisely Pledge provides a framework for best practices in reducing radiation exposure. The pledge tenets include the following:
• placing the patient’s safety, health, and welfare first;
• conveying the principles of the program to the imaging team to ensure optimal use of radiation;
• communicating optimal patient imaging strategies to referring physicians and being available for consultation;
• routinely reviewing imaging protocols to ensure the least radiation necessary to acquire diagnostic-quality images; and
• monitoring examination radiation dose indices to enable comparison with established diagnostic reference levels.
In addition, a best practice of monitoring examination radiation dose involves utilizing technologies that alert radiologists and technologists to any red flags when dose is being administered. Jennifer N. Walker, coordinator of MRI/CT in the School of Health Sciences at Southern Illinois University in Carbondale, provides an example of how such technology comes into play on the CT side of imaging. “Automatic exposure control and CTDI [CT dose index] helps technologists with dose. CTDI monitors how much dose a technologist is administering to the patient, and this can be monitored per scan or per body part. Typically, this comes with the new CT systems, and it provides an alert when too much dose is given. Automatic exposure control also provides better control of patient radiation dose,” Walker notes. Other tools Walker mentions include the following:
• Auto mA measures magnitude, which is determined from the attenuation level at each location, eg, shoulder-high attenuation, thorax-low attenuation, or liver-moderate attenuation; high attenuation is bright on an image, indicating high density.
• Bismuth shielding is used for protection of superficial radiosensitive organs; it is used for radiologists and technologists standing in the imaging room.
• Dose length products, or DLP, are a measure of CT tube radiation output/exposure.
• mA modulation is adapted to body parts and not patient weight, as thinner body parts need less radiation.
• Smart mA adjusts tube current during each rotation, both longitudinal and angular modulation.
• Organ dose modulation, or ODM, is based on smart mA and reduces the mA on the anterior sides of the patient where sensitive organs exist.
“Most of these tools are built into the machine,” Walker says. “They reveal how much dose has been administered per body part. All of this can be added together to reveal how much dose is given for the entire exam.” She adds that such devices are relatively new developments in imaging technology. “We began seeing more of them in the last five years.”
Schueler says numerous tools focused on lowering radiation dose have been introduced in the past several years. “I work with several of these new technologies as a medical physicist, helping to optimize image quality at a low radiation dose,” she says. “Some examples include image noise reduction software algorithms for CT, flat-panel digital detectors for radiography and fluoroscopy, and slot scanning radiography for spine imaging.”
Benefits vs Risks
Another best practice that Schueler mentions involves the concept of justification and optimization for radiation protection. “Justification for the conducting of the procedure ensures that benefit outweighs the risk,” she explains. “Optimization of the radiation dose is used during the procedure to ensure that risk has been minimized.” She adds that best practices related to justification include providing materials for informed clinical decision-making, such as access to a patient’s prior examinations and appropriate use criteria for the particular indication. “Best practices related to optimization include initiatives to compare patient doses to accepted benchmarks or reference levels and incorporation of radiation dose display, recording, and reporting,” she says.
Schueler says the principles of justification and optimization come into play again when determining which examination provides the most benefit to the patient at lowest possible dose. “Justification requires an analysis of the potential clinical benefit of performing the examination weighed against the potential risks,” she says. “When an ionizing radiation imaging procedure is determined to be appropriate, optimization should be applied to implement strategies that allow for the use of radiation doses that are as low as reasonably achievable without compromising the procedure.”
Sandi Watts, MHA, RT(R), ARRT, is Walker’s colleague at Southern Illinois University’s School of Health Sciences, and she brings a radiography perspective to the topic of best practices. In radiography, best practices involve shielding everyone of child-bearing age and all children, as well as generator usage. “The high-frequency generators currently deployed are the ones most often used, as they administer the smallest amount of radiation,” according to Watts, the interim program director and an associate professor of radiologic sciences at the School of Health Sciences.
Other current best practices, Watts says, include strong communication among physicians, technologists, and patients, with understandable explanations about what is necessary, the feasibly smallest amount of radiation for effective imaging, avoidance of imaging study repeats, and protection for the department or imaging center professionals. Staff protection includes thyroid shields and lead-lined glasses.
“Protection also involves making the occupation people aware of the areas in a room where it is best for them to stand, to avoid exposure,” Walker says. “For instance, with CT, people need to know to stand at the side of the scanner, instead of at the front, to get less scattered radiation exposure.”
Need for Increased Education
Ever-increasing concern about radiation safety has led to a perceived need for more education, not only for patients but also for professionals. Indeed, one part of Image Wisely’s mission is raising awareness and providing the latest education resources for imaging professionals and referring physicians about exposure to ionizing radiation. The initiative communicates the availability of this material and disseminates the materials through electronic and print forms of media. In addition, members network with affiliated health care organizations, educational institutions, and government agencies.
Even in this era of misrepresentational social media and suspect internet resources, online technology remains an effective virtual communication and dissemination tool. “Much of the new educational materials are made available on reliable websites and social media,” Schueler says. “Professionals and patients are able to learn about radiation dose in medical imaging from numerous online educational resources.”
Schueler describes a factor that compelled the need for increased education. “Several key recent publications reported specific cases of high radiation dose and increased use of diagnostic imaging, particularly in CT,” she says. “These publications raised public awareness and resulted in increased efforts to reduce patient dose and educate physicians regarding radiation exposure.”
As the public has become more aware, health care professionals perceived the need for more education for patients—and for themselves. “As the public’s awareness of radiation exposure has increased, there has been greater need for imaging professionals to be knowledgeable about radiation effects and the doses patients receive,” Schueler says. “Also, regulatory requirements for radiologist and technologist education in CT and fluoroscopy safety have driven an increase in courses and training materials related to these subjects.”
Continuing education helps meet the need, Walker says. “It is so important because there are so many new technologies and exams always being developed.”
Schueler feels that the physician-to-patient educational component is crucial. “Patients need adequate information to be engaged in shared decision-making with their physician in all health care choices, including those related to diagnostic imaging,” she says. “Communication of the benefits and risks of medical imaging procedures assists patients in making informed decisions and avoids unfounded fear and anxiety. So, it is also advisable to use clear, everyday language, avoiding technical and medical jargon.”
In this way, good communication enables patients to have a reality-based understanding of the situation. “Some patients harbor the misperception that if they have only one chest X-ray, they will be at a much greater risk of lung cancer, so it is important to let patients know just how much radiation they’ll receive, so they don’t think they are getting damaged,” Walker says.
“It’s important they know that they are going to receive only a very small amount, so that if there is a need for a repeat, they won’t think they are at an increased risk,” Watts adds.
With better communication and education, the issue of risk vs benefit becomes clearer for patients, and that can be of vital importance. In some cases, the risk of not undergoing an imaging diagnostic test can far outweigh any risk associated with radiation exposure.
“Risks of skipping a needed diagnostic imaging procedure include inaccuracy and delay in both diagnoses and treatment,” Schueler explains. “Imaging may replace exploratory surgery, which may entail several greater risks such as anesthesia and infection. In addition, though low-dose imaging techniques may be appropriate for screening or specific imaging procedures, higher doses may be required to obtain diagnostic-quality imaging in some circumstances, thus avoiding the need for repeated imaging or longer procedure times.”
Watts puts it bluntly: “A patient can end up being much more worse off without diagnostic imaging than if they went ahead and had the imaging.”
— Dan Harvey is a freelance writer based in Wilmington, Delaware.