We can always rely on you to have friends and family members on the cutting edge of every possible situation in order for you to draw your expertise, however in 1984 the commercial PET scan was in it's developmental stages and it's widespread use was still several years away. In 1984 Alzheimer's testing was limited to ruling out Parkinson's and Dementia, brain imaging wasn't used..... even on the President. Ron Regan Jr. is using his 20/20 hindsight to sell a book, nothing more.PET & SPECT scans of the brain can show it. I know. I had 2 family members and a friend scanned and diagnosed by it.