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The medical physics community is leading the effort to simplify the CT protocol.
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The medical physics community is championing the effort to simplify at least one element of the LCS program: the CT protocol.

October 01, 2019

With all of the daunting obstacles — economic viability, primary care provider buy-in for shared decision-making, and population disparities, to name a few — establishing a lung cancer screening (LCS) program is challenging. However, the medical physics community is championing the effort to simplify at least one element of the LCS program: the CT protocol. 

In 2010, the American Association of Physicists in Medicine (AAPM) spearheaded the formation of the Working Group for CT Nomenclature and Protocols. This collaborative committee was created largely in response to misuse and misunderstanding of CT equipment. In addition to a large and diverse group of practicing medical physicists from the AAPM, the committee has representatives from CT manufacturers, the American Society of Radiologic Technologists, the ACR, and the FDA. One of the major deliverables of the committee — now called the Alliance for Quality CT (AQCT) — is to publish safe and reasonable CT protocols in the public domain for select adult and pediatric exams.

Following the U.S. Preventive Services Task Force B grade for low-dose CT in December of 2013, the AQCT first published LCS CT protocols in 2014. The 2014 protocols included CT scanners from Canon (then Toshiba), GE, Hitachi, Neusoft, Philips, and Siemens. These protocols were developed and reviewed in coordination with the CT manufacturers and vetted by clinical physicists with experience in LCS trials. The protocols offer reasonable low-dose scans with image reconstruction settings optimized to provide the required spatial resolution. As LCS volumes increased with the 2015 CMS national coverage determination, these protocols provided a valuable resource for the community to refer to a variety of scanner makes and models. In 2016, the LCS protocol document was downloaded nearly 10,000 times. The most recent update to the protocols was published in July of this year. The updated LCS protocols are particularly important because they incorporate the latest CT models and software advances from each of the manufacturers, while maintaining a stable of protocols for the large existing install base of older models. These protocols can serve as the starting point for discussion within the CT protocol management team at an institution or across a practice.

According to Debra Dyer, MD, FACR, chair of ACR’s LCS 2.0 Steering Committee, “The AAPM and the AQCT are important allies in our efforts to increase the adoption of LCS. Their initiatives to optimize CT protocols and minimize dose in LCS provide valuable tools for the implementation of screening programs.” In addition to developing consensus CT protocols, the AQCT also works to develop educational resources for the CT imaging community. One of AQCT’s current projects is working with CT manufacturers to create updated education slides to help users understand how advanced automatic exposure control (AEC) features operate and can be implemented to optimize image quality and dose. The AQCT originally published CT radiation dose education slides in 2013, with specific details and screenshots for each vendor in a self-contained document. These slides include information on how acquisition parameters and AEC features affect radiation dose and have been downloaded thousands of times. Many institutions utilize the slide sets to help meet Joint Commission requirements on continuing education for RTs. The ongoing work to update the AEC content recognizes the significant changes in technology and features since the slides were first published. The committee expects to finalize the work on the new educational content this year. 

The website also includes the committee’s lexicon to facilitate translation of vendor-specific names for features to a standard terminology, and educational materials about the operation of CT Dose Check features on scanners. The work of the committee was recognized by the FDA in 2013, when the group was awarded the Center for Devices and Radiological Health Director’s Special Citation Award “for developing CT imaging radiation safety instructional materials through a collaboration of end-users, CT manufacturers, and the FDA.” 

The group is committed to continuing to develop additional protocols and educational materials to serve the imaging community and welcomes input for potential new projects or feedback on existing materials. Dyer adds, “We are very fortunate to have the expertise and commitment of the medical physics community to keep our radiology practices and staff updated on the technical advances to enhance our CT protocols and, ultimately, patient care.”

Author Mark P. Supanich, PhD, assistant professor of diagnostic radiology and nuclear medicine at Rush University Medical Center, and Dustin A. Gress, MS, ACR senior advisor for medical physics