By Janet Raloff

Web edition: August 17, 2009

Each week day throughout the United States, health centers typically perform some 7,500 or more bone scans using a nuclear isotope, technetium-99m, to search for areas of rapid bone growth, which might signal cancer. Since May, however, the low and erratic availability of this isotope's feedstock — molybdenum-99 — has put access to these tests in jeopardy. The good news: There's an alternate imaging test available that's as good as the one that relies on Tc-99m.

The not-so-good news: Your doctor or medical center may not offer it.

The Food and Drug Administration recently posted a Q&A on its website offering suggestions about how health-care providers can cope during the current technetium shortage. One recommendation: Where bone lesions are suspected, physicians should consider substituting sodium-fluoride positron emission tomography, also known as NaF-18 PET imaging.

The American College of Radiology, Society of Nuclear Medicine, Academy of Molecular Imaging, American College of Nuclear Physicians and American Society for Radiation Oncology all concur with FDA’s recommendation. But one hiccup (and it's a big one): Medicare won’t pay for PET bone imaging. And don't count on insurance companies to bail us out, because they often take their guidance from Medicare policy on which procedures to cover and which to exclude. All of which could make the idea of substituting PET bone scans for Tc-99m-based tests a nonstarter for any but the very rich. 

In a July 2 letter to the federal Centers for Medicare & Medicaid Services, better known as CMS, the five medical societies petitioned the agency to alter its PET-exclusion policy, if only for periods of critical moly-99 shortages — like now.

“We strongly believe that the evidence indicates that NaF-18 PET is equal or superior to the current covered technology in identifying bone metastasis of cancer, and encourage CMS to cover NaF-18 PET for this purpose without restriction.” The letter also pointed out that “No safety issues have been reported with NaF-18, and FDA conducted a formal review of PET drugs in 2000 that specifically deemed NaF-18 to be safe and effective.” 

The current Tc-99m shortage only “lends urgency to this reconsideration,” the letter said. It concluded with five pages synopsizing studies that indicated this PET technology might even be superior to Tc-99m bone imaging.

I contacted CMS to confirm it doesn’t cover PET bone scans and has no immediate plans to change its policy. Late Friday, Donald McLeod of CMS emailed me to say that at the prompting of the five medical societies, CMS is now reevaluating its exclusion of coverage for PET bone scans. But, he pointed out, “By Medicare law, CMS takes between 9 to 12 months to review the literature surrounding an issue, make a ‘reasonable and necessary’ coverage decision, issue a proposed decision, allow 30 days of public comment on the decision, and then issue a final coverage decision.”

Bottom line, he said: No final decision should be expected before “March 2010.” Which means, I guess, that we had all better “elect” to not get bone cancer while either of the world's two leading moly-99-producing reactors are shut down. That's until early next year for the Canadian reactor outside Chalk River, Ontario. And then another four to six months after that as the Dutch reactor in Petten undergoes repairs for corrosion, beginning some time next February.

Currently, the White House Office of Science & Technology Policy is coordinating an interagency panel on dealing with the moly-99 crisis. Jean Cottam, OSTP's assistant director for physical sciences and engineering observes that "we have FDA and HHS [the Department of Health and Human Services] at the table during these discussions."

She notes that CMS can waive its normal timetable and expedite reviews if FDA declares there's a medical emergency warranting it. "A lot of health care providers have pushed for this," she says. "And we have talked to the FDA about it."

But for now, both FDA and OSTP's interagency group are encouraging doctors to triage their supplies of Tc-99m, reserving them for procedures that have no good — or available — alternatives.

Like bone scans for cancer. Indeed, notes Jeffrey Norenberg, director of radiopharmaceutical sciences at the University of New Mexico in Albuquerque, "The average hospital is ill-equipped to convert to sodium-fluoride bone scans." At best, "nationwide we're probably looking at being able to convert only perhaps 10 percent of those bone scans to sodium fluoride," he estimates.

What the nation really needs, he, Cottam and others argue, is reducing our reliance on the five very geriatric foreign reactors that are currently making 95 percent of the world's moly-99. After years of the medical community petitioning for new sources, moves are finally afoot to develop them — and from domestic facilities. Spearheading this policy shift: the Obama White House.