CT dose management is getting more attention than ever before, resulting in awareness campaigns, updated standards and numerous technological advances. According to a new commentary published in the American Journal of Roentgenology, however, the implementation of these changes is “often suboptimal.”
A group of researchers from the department of radiology at the University of Wisconsin-Madison, including lead author Timothy P. Szczykutowicz, PhD, examined how the medical imaging industry has responded to awareness of CT dose management being at an all-time high. Though the industry’s efforts are will-intentioned, the authors explained, there are some specific issues that must be addressed. These are four of those issues:
1. The CT Dose Check standard creates problems for users.
CT Dose Check, part of the Medical Imaging & Technology Alliance (MITA) larger CT Smart Dose standard, was designed to alert CT operators whenever the estimated radiation dose exceeds certain preassigned values. Szczykutowicz and colleagues noted that problems with CT Dose Check are causing headaches for imaging providers.
“Because notification values are fixed and independent of patient size, appropriate doses for bariatric patients may inappropriately trigger notification events and associated incident reviews required by The Joint Commission,” the authors wrote. “Of more concern, exceeding the alert value completely stops workflow on the scanner until a user with the proper credentials authorizes scan continuation. However, the alert value can and is exceeded during some common CT interventions (e.g., arthrography, biopsy, ablation, and other interventions).”
MITA is aware of these issues and working to address them, the authors added, but “this update will likely take several years to be propagated on currently installed CT scanners.”
2. Some imaging sites aren’t using automatic exposure control (AEC) systems.
“A lack of expertise, combined with the complexity of setting up AEC systems coupled with a fear of exceeding defined dose targets, has resulted in some sites not using AEC,” the authors wrote. “Each CT vendor provides an AEC system, but they use different methods for control and allow scan parameters to affect AEC operation in complex and vendor-specific ways.”
Szczykutowicz et al. explained that protocol development requires CT operators to possess “considerable expertise in AEC operation.” Also, when users lack such expertise, it has potential to reduce their confidence in their own equipment.
“This is made evident by the practice of setting dose targets according to patient age and having CT technologists adjust parameters until the targets are met,” the authors wrote.
3. Classifying, aggregating CT dose data remains an imperfect science.
Many dose data registries exist, but they are far from perfect. They lack a universal naming convention, for example, which makes it harder to gather accurate, useful information from the registries themselves. In addition, organizing add-on examinations can create its own challenges.
“A common example at our institution involves routine head CT examination with an add-on scan of the cervical spine,” the authors wrote. “The American College of Radiology (ACR) Dose Index Registry cannot separate these two examinations if they are performed together, resulting in reports of artificially elevated dose levels for both examinations. An ACR Dose Index Registry representative advised us to make a new combination of dose mapping for such examinations and a new protocol on our scanner for use with such combinations; however, 40 percent of our examination categories involve add-on scans, making this logistically prohibitive.”
At the end of their analysis, Szczykutowicz and colleagues pointed out that “poor execution is a consistent theme” in today’s CT dose management. A team approach, they concluded, is the industry’s best way to correct these issues and move forward.
Michael has more than 16 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.