I'll add something. You are correct about staying with the same dexa scan equipment. It's important but it may not always be possible. I had my scans done every other year for a number of years on the same eqipment. Several years ago I went back to the same medical center and they had switched to a new system. They did the scan as usual but they couldn't compare my new scan the same way as before. Of course they could get all the readings or measurements, but they couldn't compare the latest results with the previous ones. Two years later they could at least compare my new scan to my previous one. Technology changes over time and medical centers have to update their equipment.