Investigators in a recent study of digital tomosynthesis (DT) say the technology has the potential to become a viable alternative to lung cancer screening, but further research is needed to reach that conclusion.

Since National Lung Screening Trial (NSLT) testing began in 2002, CT screening for lung cancer among smokers between 55 and 74 years old has shown that a reduction of 15 to 20 percent in mortality is possible in the future, according to the National Cancer Institute at the National Institutes of Health (NIH).

While CT remains "the 'gold standard' for imaging pulmonary nodules," DT delivers a lower dose of radiation and costs less than CT screening, James T. Dobbins III, associate professor of radiology, biomedical engineering and physics at Duke University, told DOTmed News. Dobbins and his colleagues studied lung nodule detection as part of a two-year study funded by GE Healthcare, which included 158 people at three institutions in the U.S. and one in Sweden.
According to the study, the radiation dose for a DT test is 0.1 MilliSievert compared to 5 MilliSieverts for a thoracic CT. While DT is less expensive, Dobbins said it will be challenging to determine the reimbursement rate within the U.S. health care system, and the question of cost has not been "fully resolved."

What distinguishes this research from earlier studies is the fact that it used radiology readers who are not thoracic radiology experts, which better reflects "what you might experience in a general radiology setting," Dobbins said. The manuscript of the study will be released in Radiology in the next few weeks.

"The question that remains is, how will we use this tomosynthesis technology clinically?" Dobbins said. One possible use he suggested for DT would be "as a problem-solving tool" to eliminate the need to send some patients to CT to rule out or confirm a nodule after an indefinite finding on chest radiography. "If you can prove either that a nodule is present or that something in fact is not a nodule, then you've saved sending that patient to CT."

While another possible application for DT would be "following nodules over time that had been found by CT," Dobbins said its use "in a lung screening paradigm" would require about five more years' worth of research.

Ella A. Kazerooni, a University of Michigan radiology professor and director of cardio-thoracic radiology who was an investigator in the same study, said the DT technology is "too new and too untested," but it has a high detection rate for larger nodules.

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