Over the last several years, Duke University Medical Center’s monitoring program for CT performance has undergone some big advancements. These included incorporating CT study image quality metrics to augment the more standard radiation dose profile of each examination, with monitoring of performance by a multidisciplinary team on a regular basis. From creating a set schedule for dose monitoring reviews to organizing accounting and database protocols, the North Carolina institution has taken steps to enhance its program.

“Several years ago, discussions on dose monitoring practices were on a random basis. It would be primarily through protocol review which we tried to do regularly to see that the doses we were delivering were reasonable, but the benchmarks weren’t well developed,” Dr. Donald Frush, a professor of radiology and pediatrics in Duke’s department of radiology, told HCB News. “The development of that formal program has allowed us better data to begin to address what we do and how to improve our service.”

Today, staff members meet quarterly for reviews, searching for outliers to identify areas in need of improvement and formulating approaches to make those fixes. Accounting and database protocols are also in check thanks to the introduction of a server.

Experts like Frush have witnessed similar transformations across the country in radiation dose management through the introduction of updated guidelines, assessment programs, accreditation, and technological innovations to ensure patients remain safe and receive appropriate amounts of radiation to address their individual imaging needs.

But dose optimization goes deeper than just understanding how radiation management works. It requires a broader knowledge of CT and its usage, from technique to scan prep time, to knowing when a CT scan is or is not the right thing to do.

Dose rates are safe? Prove it.
Almost every facility with a CT scanner today requires some form of accreditation in order to gain reimbursement for exams. In addition to most, if not all, payors, even states are now demanding some form of credentials from providers to demonstrate the safety of their environment and practices.

Obtaining certification varies by accrediting organization, with each requiring facilities to meet certain criteria. The Intersocietal Accreditation Commission (IAC) for instance requires facilities to have a consistent quality assessment program to ensure that periodic random checks of patient radiation exposure rates take place and to review and compare actual patient radiation dose to predetermined doses to avoid overexposure or assess what factors led to it taking place.

“Maybe the patient was very large, or needed to have a repeat exam because they moved, or perhaps your staff members inadvertently selected the wrong technical factors. That’s what you need to check periodically to make sure your patients aren’t becoming erroneously irradiated,” said Nancy Merrill, director of accreditation for MR/CT/Carotid stenting at the IAC.

Further guidance can be found through programs such as Image Wisely, which provides resources and information on ionizing radiation exposure from medical equipment to radiologists, medical physicists, other imaging practitioners and patients; or Image Gently, which supplies guidance for effective and safe imaging of pediatric patients.

Tools such as the American College of Radiology’s Dose Index Registry are also available. Using the ACR registry, clinicians can compare the range and output of their dose index data to that of their peers and similar facilities throughout the country and in their individual regions, and learn and adopt measures to meet quality and safety requirements.

“The latest technology always comes with a great cost, one that not all facilities can afford,” Debapriya Sengupta, manager of national radiology data registry analytics at the ACR, said. “Dose Index Registry provides high-value but low-cost tools so that all facilities can provide high-quality patient care and meet their Leapfrog reporting requirements.”

While important, dose management and safety is just one area that must be assessed when exposing patients to radiation from CT and other imaging modalities. Clinicians must ask themselves if CT is the correct modality of choice or if there is another that exposes a patient to less or no radiation at all. Furthermore, they must question their own practices in utilizing CT and how those influence the outcomes of procedures and the overall health of patients.

To scan or not to scan
CT utilization has dropped in the past ten years by roughly 20 percent for Medicare beneficiaries, with heightened attention to dose practices playing an integral role. This change in attitude toward dosage is derived from greater emphasis on the appropriate use of CT with clinicians questioning and communicating with one another more often on whether CT is the right option or if another diagnostic tool would be a better option.

“Maybe a physician thinks that performing a CT is appropriate but then the order goes to the diagnostic imaging group that says, ‘This really would be better if it were an MR,’” said Merrill. “They’ll call the physician who may usually agree and send a different script. Or he or she might say, ‘No, my patient has a pacemaker so you need to give them a CT.’”

Image Wisely, Image Gently and RadiologyInfo.org have made information on imaging exams that do not utilize ionizing radiation more accessible. The ACR’s Appropriateness Criteria, which offers guidance on the most appropriate tests for specific clinical conditions, is another powerful tool for choosing the right exam for the right patient.

It’s important that providers understand such tools are merely guides and not tell-all instructions. “The Appropriateness Criteria isn’t meant to be a cookbook of medicine but to help the ordering physician have the most current information and promote those conversations addressing what the experts have said about this condition,” said David Kurth, senior director of the ACR Practice Parameters and Appropriateness Criteria.

In addition to clinicians, the responsibility of knowing the risks of CT use falls on patients themselves and is on the rise as more engage in consultations and shared decision-making with their physicians on which exam is the right choice based on their condition and individual needs.

But while the drop in CT exams among Medicare beneficiaries may appear positive due to the decrease in ionizing radiation exposure, statistics on total utilization are limited due to a lack of any reliable source of information on non-Medicare patients. At the same time, the extent to which each factor has contributed to this decline is uncertain.

“With CMS mandating the use of appropriate use criteria in 2020, it should become less of an issue,” Jason H. Launders, director of operations for Health Devices Group at the ECRI Institute, said. “However, it isn’t clear how much of that is being driven by financial concerns or dose concerns.”

Technique and technology
The actions of the patient before and during the exam make all the difference. For example, movement during a CT scan can lead to repeats of procedures, exposing patients to more ionizing radiation.

“Patients, especially children, can be somewhat anxious about the scan or outwardly frightened,” said Duke’s Frush. “To have parents in the room, some preparatory information available, child specialists or anticipatory training for patients and parents, can allow the scan to happen more efficiently, with less chance for movement-affected scan quality.”

Ensuring patients are calm and prepared is part of scan preparation, one of two components (scan preparation and scan performance) according to Frush that determine the success of a CT scan. Movement and improper positioning can degrade quality and diagnostic information, and if extreme, may necessitate re-scanning with additional radiation exposure.

Errors such as incorrect positioning in the gantry, improper arm or leg positioning, or not immobilizing a young patient (when needed) can contribute to overexposure and stress the need for providers to develop and implement comprehensive protocols that are mindful of preparation for children throughout their practices.

“Without adequate preparation, you may have detriments to scan quality and that means the dose you use is connected to a scan of reduced quality, less ‘bang for the buck’,” said Frush. “In pediatric radiology, and I think likewise for adult radiology, it is important to look at the fundamental basics of scanning, such as preparation, because this increases study quality, potentially reducing patient dose while provide better diagnostic yield.”

In conjunction with correct technique is the other component, technology, which continues to evolve through research and development, such as with the release of a new detector or the discovery of a faster scanning method for decreasing motion. One example is the wider availability over the last few years of dual energy CT technology, which enables clinicians to gather information from a single phase alone and to preclude pre-contrast and post-contrast study.

Another is the incorporation of automated technical factors in scanners that enable radiologic technologists to prep for exams more accurately and avoid exposing the patient to excessive amounts of dose.

Many payors require that such features be assessed as part of the accreditation process to ensure their use equates to safe dose rate applications. “That includes specific technical factors such as your kV, mA or mA range, rotation speed, and pitch – that are very specific items to ensure they are appropriate, with an acceptable radiation dose,” said Merrill.

One approach to ensure such standards are met has been the introduction of XR-29, requiring CT facilities to implement processes to record and assess the exposure of their doses to keep them within reasonable ranges. In effect, its use has raised accountability among providers in their administration of radiation and efforts to optmize dose delivery.

Understanding the full functions and uses of current developing technologies such as AI as well as technique is crucial says Frush, who sees them as integral parts in the calibration and delivery of correct dosage in the coming years.

“We need to promote the fact that CT has saved countless lives by continuing to question how we are going to make sure dose is right for the examination. I think we can look at advances with AI and how we are beginning to leverage that in terms of being able to assess image quality. We’re also evolving to have organ dose estimations now supplant what we typically have had, which is CT dose index volume (CTDIvol) and size-specific dose estimation (SSDE). Having this more granular, organ-based dose information for each patient’s scan can also enhance the dose component of a comprehensive CT performance monitoring program.”