A need to know: Is it Alzheimer's?

For almost three years, Janelle Lafser pleaded with doctors to order a PET scan for her husband, Frank.

He had been experiencing memory and mood problems -- beginning at age 45 -- and was having trouble in his job as an executive at a paint company. The doctors said he was depressed, but Janelle was unconvinced.

She told them that her husband forgot plans the couple had made, misplaced things and found paying bills too confusing. She suspected Alzheimer's disease and wanted the positive emission tomography test because it can provide physical evidence of the disease.

Physicians steadfastly refused, telling her that Frank was too young to have Alzheimer's, which occurs mostly in people age 65 and older. "I think you want that diagnosis," an exasperated neurologist told Janelle one day when she again requested a PET scan to look for Alzheimer's.

"I want the truth," she snapped back.

Finally, when his doctors recommended electric shock treatments for depression, Janelle made it contingent upon a PET scan that showed no abnormalities. Only then did the Lafsers, who live in La Quinta, get the scan. As Janelle suspected, Frank had Alzheimer's disease.

Until recently, PET scanning has been seldom used in the diagnosis and treatment of Alzheimer's, even though it is billed as "a window to the brain" and is the only test, other than an autopsy, to offer physical proof of the disease. At about $1,500 per exam, doctors have deemed it too expensive and too experimental, with many saying a scan would be of little practical benefit to a patient with an incurable disease.

But some families have increasingly countered that they need a specific diagnosis of Alzheimer's -- backed by a PET scan -- to ensure proper treatment and to plan for their loved ones' gradual deterioration.

Now, more of them will know what type of treatment to pursue and whether to make long-term arrangements. In October, Medicare announced that it would begin to pay for PET scans in some patients with signs of the disease, a move that is expected to lead to increased coverage by private insurers as well.

That move could be just the beginning. Many experts predict that, within the next decade, PET scanning also may be recommended for healthy people who lack symptoms but who are at high risk for developing the disease. For these people, the tests may determine whether their brains are already exhibiting signs of degeneration.