most people don't know, but there was a medical 29th century Tricorder built for Voyager. It had a "slide in" compartment on the back of the Tricorder with a very slim medical scanner. The Scanner was re-used in season 6, ep. 12 "Blink of an Eye" as the whatever-time-synchronizing-device of the guy visiting Voyager at the very end of the episode (slightly modified though). Also, it was at some point given to Seven by Capt. Braxton as some kind of scanner (?), I don't remember Relativity right now...
For some reason the medical Tricorder never made it on screen, but it was built.
The scanner had very nice electronics with LEDs circling the round opening in the colors red, green and blue. I actually built one many, many years ago and had pictures and a movie up on TPZ, but that is all gone now. I still have it somewhere in a box though. Still one of my favourite builds. The modified medical Tricorder was re-used at some point by a fellow prop builder when the original bodies became rare, so it no longer exists.
Hope I could help!