Have you or anyone you know ever had a serious medical problem diagnosed with a CAT Scan or MRI? You quite literally owe a life to the Space Program.
Well mine was not really discovered by means of one of those, although they helped in making sure about it and monitoring the progress of the disease. However what I'd really like is a medical tricorder and even more importantly, the associated therapeutic technology. I imagine that both in the 23rd and in the 24th century the doctor would stop me and say: you have to stay for ten minutes to remove some tumoral cells... and the next day I would wake up just as fine as I've ever been. But it's not like that yet! ;-)