The Right Dose: Quality Measures to Improve CT Safety and Efficacy

By Sharon Breske

Producing radiation doses far higher than conventional x-rays, CT imaging has remained a topic of contention for years, both inside the imaging community and in the public eye. Compounding the issue is a significant performance gap among radiologists and health care organizations regarding CT use, which can potentially—and unnecessarily—harm patients.

To address these concerns, the Radiology Outcomes Research Laboratory at the University of California San Francisco (UCSF) is designing a measure to evaluate CT image quality and radiation safety, said Rebecca Smith-Bindman, MD, director of the lab and professor of radiology, epidemiology, and biostatistics at UCSF. Funded by a grant from the Centers for Medicare & Medicaid Services (CMS) and the Patient Centered Outcomes Research Institute (PCORI); the project aims to ultimately serve as a framework for standards-based dose assessment, benchmark comparisons, and corrective action across the field.

Kieran Anderson speaks with Dr. Rebecca Smith-Bindman about the study.

The project stems in part from a shift in how CMS is paying for physician services, moving from quantity to quality of care under the Merit-based Incentive Payment System (MIPS).

“To move to a quality-based payment system [requires] quality measures, and CMS identified several areas where they felt good, meaningful measures were in short supply. One of those areas was radiology,” said Dr. Smith-Bindman, who is also a member of the UCSF Philip Lee Institute for Health Policy Studies. “Our goal is to figure out how we assess CT scans and create thresholds that most radiologists will consider adequate for diagnosis. It could have a meaningful impact in clinical practice by assuring doses for CT are not too low based on the opinion of a large number of radiologists.”  

While it is paramount that CT doses are no higher than needed, they must also not be so low that it hampers image quality. “The goal is not to reach to the bottom and have the lowest dose,” she stressed. “The goal is to have the right dose.”

The project, titled “DR CTQS: Defining and Rewarding Computed Tomography Quality and Safety,” involves creating a framework for assessing CT scans that considers both radiation dose and image quality. As part of determining the image quality requirements, the study uses a web-based test set ( asking radiologists to analyze images to help determine measures of quality. The test set consists of about 750 random cases with subsets of roughly 200 cases and takes a couple of hours at most to review, she noted. The cases reflect current practice and are chosen from a range of manufacturers and doses. Radiologists can participate through January and will receive a $400 Amazon Gift Card for their input.

“We're asking radiologists to look at the quality of the images—not make diagnoses—and tell us whether those images are adequate for diagnosis, marginally acceptable for diagnosis or inadequate,” she said.

Dr. Smith-Bindman is hoping to recruit U.S. radiologists across all realms of practice. “We want this to be a reflection of what radiologists in the United States think is adequate image quality,” she said, “which means I want all kinds of radiologists to look at these images and share their perspectives regarding which images are adequate and which are not.”

Once input is collected, the project will use artificial intelligence (AI) and different measures of image noise to automatically determine in a rapid feedback loop whether images are acceptable for diagnosis based on the radiologist’s judgements.” she noted, “our goal is to [help set] the standard for image quality using AI techniques.”

Overall, concrete standards for image quality will not only improve patient care and safety but will help radiologists meet imaging benchmarks as opposed to today’s norm of “every radiologist, radiology group, hospital and facility recreating those benchmarks and determining the acceptability on their own,” said Dr. Smith-Bindman. “It will make the job of radiologists and, in fact, the manufacturers, easier going forward.”

For more information about DR CTQS, contact Dr. Smith-Bindman at

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The Right Dose: Quality Measures to Improve CT Safety and Efficacy.  Appl Radiol. 

By Sharon Breske| January 14, 2020
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Sharon Breske

Sharon Breske

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