Throughout season 1, the Visitors have used their medical equipment to treat humans at the Visitor Healing Center.
The diagnostic scan is a devise which scans the human body and can find anything that is happening wrong in the human body.
When Chad Decker went to the Visitor Healing Center, he underwent a diagnostic scan and found out he have a aneurysm. It is possible that the Diagnostic Scan can actually find out the medical history and what will happen in the days to come.
- Main article: R6
R6 is a chemical compound which embeds itself in human DNA, and emits a signal that allows the Visitors to track to anyone injected with the compound.