It might be more like the PET scan and MRI business, with select hospitals buying huge, expensive machines.

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The marker used in the PET scan -- the one that binds to tau -- is called FDDNP.

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Similarly, a PET scan of Kate Bainbridge's brain one month before she started to recover showed surprising levels of brain activity.

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Occasionally, a PET scan is tossed into the mix.

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How about a PET scan in Portland?

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