An emerging discipline in radiology, quantitative imaging has enormous potential in oncology research as a means of predicting and measuring response to cancer therapy.
Through its unique ability to extract defined information in vivo, quantitative imaging could facilitate adaptive therapy trial strategies allowing alternative treatment regimens when initial therapy response is ineffective. “Quantitative imaging can potentially help determine as early as possible if one or more drugs are working so that therapy can be modified,” said Laurence Clarke, Ph.D., branch chief of imaging technology development for the National Cancer Institute’s (NCI) Cancer Imaging Program. “The ability to predict and/or measure therapy response should provide a more robust means for both therapy dose management and correlation of imaging results with other laboratory biomarkers.”
But researchers excited by this potential are also frustrated by limitations in methods used to determine cancer treatment response, including reproducibility of measurements, incomplete data collection and poor radiologist-oncologist communication. To that end, NCI is conducting a number of initiatives within its Cancer Imaging Program designed to develop a broad consensus on quantitative imaging methods and to encourage the adoption of more standardized methods for quality assurance and quantitative imaging.
One such initiative—the Quantitative Imaging Network (QIN)—was designed to promote research and development of quantitative imaging methods for the prediction and/or measurement of tumor response to therapies in clinical trial settings, with the overall goal of facilitating the development of clinical decision support systems. QIN has made considerable headway since its founding in 2008.
“The QIN program was created to support multidisciplinary research teams to develop quantitative imaging methods to measure the response to therapy, using current commercial imaging platforms,” according Dr. Clarke, QIN science officer. “The teams will then optimize the performance of their quantitative imaging tools with data collected from ongoing clinical therapy trials. A goal of QIN is to provide the image, metadata, clinical outcome data and measurement results as a public resource using The NCI Imaging Archive (TCIA).”
Currently QIN researchers are developing advanced methods for collecting and analyzing data across commercial platforms with the goal of creating software tools that are operator-independent, Dr. Clarke said.
“Ideally, these tools wouldn’t require human intervention in terms of collecting or analyzing data,” Dr. Clarke said. “They would put the quantitative data in the hands of radiologists who could make decisions based on that information.”
That goal means interfacing with the makers of commercial imaging systems to develop the standards and tools acceptable for advancing industry-wide adoption, Dr. Clarke said. “We are encouraging industry participation in QIN in hopes that these large companies will take the tools developed by academic scientists, commercialize them and bring them to the clinical setting,” he said. “A large number of QIN teams are interfacing with several large and small imaging and software companies.”
Although they are separate organizations, QIN works in tandem with RSNA’s Quantitative Imaging Biomarkers Alliance (QIBA) to interface with commercial vendors. Approximately 20-25 percent of QIN principal investigators are QIBA members.
While Dr. Clarke describes QIN as a “research engine” for quantitative imaging, QIBA brings all of the stakeholders to the table to work on a common goal: to industrialize and disseminate quantitative imaging and the use of mature imaging biomarkers in clinical trials and clinical practice by engaging researchers, healthcare professional and industry.
QIBA comprises members from several academic medical centers, of the U.S. Food and Drug Administration (FDA), the National Institute of Standards and Technology (NIST), NCI, the American College of Radiology Imaging Network (ACRIN) and major imaging equipment manufacturers including GE, Phillips, Siemens and Toshiba, the Extended PhRMA Imaging Group and others. QIBA is supported by funding from the National Institute of Biomedical Imaging and Bioengineering (NIBIB).
RSNA’s overall goal in organizing QIBA five years ago was to improve the clinical value of routine quantitative imaging—an aspiration often complicated by limitations in the technology involved, said RSNA Science Advisor Daniel Sullivan, M.D., a professor in the Department of Radiology at Duke University and chair of the QIBA Steering Committee.
The problem, Dr. Sullivan pointed out, is that while clinical trials are needed to show the value of quantitative results, imaging equipment must be able to provide the needed accuracy and reproducibility of quantitative imaging data. “But in response to that request, manufacturers say that they need to know the clinical value of quantitative imaging,” said Dr. Sullivan. “It’s a question of which comes first—the chicken or the egg.”
Although QIBA is not an NCI initiative, the relationship between QIN and QIBA will ultimately facilitate NCI’s goal of promoting the role of molecular imaging in drug trials. One goal is the “qualification” of the proposed molecular imaging protocols that can be incorporated into current or future drug trials submitted to the FDA.
“FDA qualification of quantitative imaging biomarkers will be an important step toward the ultimate RSNA goal of widespread clinical use of quantitative imaging biomarkers,” Dr. Sullivan said.
Also critical to the process is the Cancer Steering Committee of the NIH Biomarker Consortium. Launched in 2006, the Biomarker Consortium was developed by the NIH and the Foundation of the NIH (FNIH) and is charged with coordinating public-private partnerships to advance the goal of standardizing and improving biomarkers. The Cancer Steering Committee focuses particularly on biomarkers, including imaging technologies, for use in development of new cancer therapies.
QIN, which continues to expand and currently comprises 16 technical teams and five working groups, held its annual meeting in March at the NIH Natcher Campus in Bethesda, Md., to update members on current issues and discuss future direction
While he doesn’t expect a mature methodology to be finalized for another 5-7 years, Dr. Clarke stressed that quantitative imaging is central to realizing NCI’s goals. In fact, imaging is now poised to be one of the first biomarker methods that may be standardized within a reasonable time line, both nationally and, ideally, internationally.
“NCI is putting major resources into drug discovery and imaging plays a critical role in terms of prediction to drug response.”
Hear Laurence Clarke Ph.D., branch chief of imaging technology development for the National Cancer Institute’s (NCI) Cancer Imaging Program, discuss:
For more information on the Quantitative Imaging Network (QIN), go to imaging.cancer.gov/programsandresources/specializedinitiatives/qin.
For more information on the Quantitative Imaging Biomarkers Alliance (QIBA), go to rsna.org/QIBA_aspx.
For more information on the Biomarkers Consortium, go to biomarkersconsortium.org.
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