Combining bone scintigraphy using sodium fluoride-18 (18F-- ) with 18F-FDG PET/CT, as opposed to performing two scans separately, has the potential to improve care for certain cancer patients and reduce healthcare costs, according to a study published online Dec. 14 in the Journal of Nuclear Medicine.
“With the availability of PET/CT, an entirely new combined radiotracer approach allows for a strategy for patient management not previously possible,” wrote Andrei Iagaru, MD, of Stanford University Medical Center in Stanford, Calif., and colleagues.
The authors explained that previous research supports the use of both bone imaging and 18F-FDG PET/CT for detection of skeletal metastases due to the varying mechanisms of radiotracer uptake between lesions. Iagaru and colleagues noted that combining the scans could prove cost-effective, so they constructed a prospective study to evaluate the potential of the approach.
A total of 115 cancer patient were enrolled in the international, multicenter trial, and all underwent three scans: 18F—PET/CT, 18F-FDG PET/CT and combined 18F--/18F-FDG PET/CT. Scans were performed sequentially within four weeks of one another for each patient.
The authors reported that the 18F--/18F-FDG PET/CT combination allowed for accurate interpretation of radiotracer uptake outside the skeleton while also boosting detection of skeletal disease. The combined scan showed more extensive skeletal disease than the 18F-FDG PET/CT scan alone in 19 patients. In 29 patients, the 18F—PET/CT scan and the combined scan showed osseous metastases where 18F-FDG PET/CT was negative, according to Iagaru and colleagues.
“[I]nstead of patients having to get a separate 99mTc-MDP bone scan or 18F-FDG PET/CT study, usually on different days, our strategy allows for a single combined PET/CT scan with potentially more utility, lower radiation dose, and greater patient convenience,” wrote the authors.
Using current reimbursement rates from the Centers for Medicare and Medicaid Services and approximate imaging utilization rates, the authors estimated that a combined scan, for those who are candidates, could save $136.5 million annually in reimbursements.
While the approach shows potential, Iagaru and colleagues pointed out they were only demonstrating the promise of the combined scan and did not assess identified lesions as true-positive, true-negative, false-positive or false-negative. “This issue will be further evaluated in future research,” they wrote.