Siegel, a professor at the Washington University School of Medicine in St. Louis, described how the reimbursement situation for PET has experienced twists and turns over the technology's history. Current Medicare policy toward PET is exclusionary -- namely, if a clinical application hasn't already been approved, it's not reimbursable.

Such a policy may have been appropriate 20 years ago in the early days of PET, but today it is obsolete and simply hinders patient access to the modality, Siegel believes.

"PET has grown up now, and it's no longer a cottage industry," Siegel said. "It's widespread throughout the country, and really it no longer needs to be regulated in this way."