This sounds to sensational to be entirely true, if it would be true I think it would have had a larger impact in society by now
"Functional MRI machines (fMRIs) are excellent at determining the brain structures involved in a task. For example, a study asking 50 people to count or remember names while undergoing an fMRI scan would accurately identify which parts of the brain are active during the task.
The trouble is that when the same person is asked to do the same tasks weeks or months apart, the results vary wildly. This is likely because fMRIs don’t actually measure brain activity directly: They measure blood flow to regions of the brain, which is used as a proxy for brain activity because neurons in those regions are presumably more active. Blood flow levels, apparently, change. “The correlation between one scan and a second is not even fair, it’s poor,” says lead author Ahmad Hariri, a professor of neuroscience and psychology at Duke University."