CT scans

I just came back from my CT scan. When got into the room I was curious because no one asked me to take off my bra as was done in the past. I asked the tech. how come. He said onc. didn't order CT of chest, abdomen only. He said chest has been clear so no reason to scan it and they want to minimize radiation exposure to the chest since nothing has shown up in the past. Has anyone had this before? I'm thinking these CT's are to see if there is any spread to lungs or liver, but now lungs aren't being scanned. I'm thinking this is a good thing...then my thoughts turn to concern that they may be missing something.