Rebecca Smith-Bindman, MD, is working with the Centers for Medicare & Medicaid Services (CMS) to implement a new quality measure that will ensure that diagnostic CT exams performed in the United States don’t exceed evidence-based radiation thresholds. The collaboration is the culmination of a career partly spent documenting excessive radiation exposure in computed tomography, both domestically and internationally. If approved by CMS, the electronic clinical quality measure (eCQM) will allow clinicians to assess and gain feedback on every CT performed. It will also identify CT protocols that result in radiation doses too high for the needed exam, and will link reimbursement levels to performance.
Smith-Bindman, a UC San Francisco professor in residence of epidemiology, biostatistics, obstetrics, gynecology and reproductive medicine, has long concentrated on the effects of diagnostic imaging on health outcomes, including patient access and testing accuracy. Because CTs deliver superior image quality versus standard X-rays, but involve significantly higher radiation levels, establishing evidence-based exposure guidelines and monitoring compliance has become increasingly important as CT use grows.
“CT is amazing technology, but we need to use it in the safest way possible,” Smith-Bindman said, noting that even after severely miscalibrated CT scans left many patients with bald rings around their heads in a 2009 national scandal, the field still has problems. “Those overdoses were extreme, but the underlying issue is in that in the ninety million CT scans performed annually in the U.S., many patients still routinely receive radiation doses two or three times what they should. That will lead to cancer in a small percentage of patients, approximately thirty-six thousand cancers every year. This means that CT causes two percent of annual cancers, and we can reduce that risk substantially without reducing the value of the scans.”
CMS gave Smith-Bindman and her team $5 million over three years to develop a measure that could be implemented in hospitals and other diagnostic imaging facilities.
“Our measure is unique in that we evaluate the CT protocols based on why the patient was evaluated,” she explained. “That provides a way to judge whether radiation doses and image quality are appropriate.”
For example, if a physician suspected that a patient had kidney stones and referred him to radiology, the radiologist would then decide how to perform the scan. She could perform a single-phase, low-dose scan that delivered roughly 2 milli-Sieverts (mSv), which is considered the correct scan to look for kidney stones. Alternatively, she could do a multi-phase, high-dose scan that might impart 25 times that amount of radiation, but which would be far higher than necessary. Because the measure will judge the scan based on the reason it was ordered, the 25 mSv dose would be considered out of range and unacceptable. Smith-Bindman’s research has revealed that patients routinely receive higher doses when the lower dose would be appropriate, and that the reasons these higher-dose scans are performed vary among providers. Indeed, when prospectively tested in roughly 48,000 CTs across 17 hospitals, the measure showed that about 30 percent of all CTs entailed too high a radiation dose. Image quality was almost always acceptable, indicating that there is no significant problem in that realm.
Smith-Bindman and her team have submitted the measure to three CMS programs that use payment incentives to drive quality – the inpatient hospital quality program; the outpatient hospital program, which includes emergency departments; and the program for physician groups. The quality measure has been unanimously endorsed by the National Quality Forum, in a rigorous process involving multiple levels of evaluation, and was unanimously recommended for endorsement by the CMS Measure Applications Partnership. The open comment period for the inpatient hospital program has just finished, with positive feedback and letters of support from more than 80 individuals and organizations including the Institute for Healthcare Improvement, the LOWN Institute, Radiology Partners (the largest radiology group in the United States), America’s Health Insurance Plans, several large hospital systems, and many patient-advocacy organizations including the AARP and the National Partnership for Women and Families.
One concern about the measure is that if physicians are incentivized to lower radiation doses, this might lead to lower image quality, but Smith-Bindman said this had been addressed in design and testing.
“Our measure sets a floor for image quality, which we established through a large physician-reader study,” she said. “Historically, it was thought that each radiologist could decide on their own what they felt was the appropriate radiation dose and image quality for each scan, as opposed to having standards that everyone follows. This led to unacceptable variation among providers.”
Smith-Bindman noted that clinicians usually get better at their jobs if they’re informed about how their practice patterns compare with those of colleagues and with established standards. “No one intentionally harms their patients; they just haven’t been paying attention to radiation dose,” she said. “The measure defines a clear standard for every type of scan with respect to dose and quality, and CMS provides incentives to reach those goals. Clinicians can exceed those targets if they deem it necessary; the measure just provides them a way to gauge their performance.”
The measure will use intellectual property developed by Smith-Bindman and her colleagues. The associated software pulls diagnosis data from the patient’s electronic health record (EHR) and ties it to the radiology data, then calculates variables including adjusted size, adjusted dose, noise and CT category. In collaboration with UCSF, Smith-Bindman and her colleagues have formed a company, Alara Imaging, which will provide the software to every U.S. hospital without charge. Alara takes its name from a principle radiologists ideally follow regarding radiation dosage – “As low as reasonably allowable.”
“We want to help radiologists implement this by making it easy to use,” Smith-Bindman said. “Alara will also provide feedback to hospitals on how to standardize their practices. Everyone in the care continuum benefits if fewer patients get cancer, most especially the patients themselves.”