I used to get them once a year unless I was sick, it would be more often. When I started my evaluations at the CC for the transplant, I would have to get them every time I went there for a follow-up, which meant at least every 2-3 months. When they look at x-rays, they are looking for any spots of pneumonia or fungus that you might not feel coming on. I know that when my lungs were getting worse, there would be more gray in the x-rays when in a healthy person, they are supposed to be perfectly black (clear).
They might also throw in CT scans every once in a while too. The CT scans show more things than the x-rays show. When I was in the hospital in November 2004 (when I found out that I needed the transplant) I had a CT scan and that's what showed the holes, fungus, and that my right upper lobe was not functioning. I think that they are necessary and I still get the x-rays even though I have had the transplant because now they are looking to make sure that they stay nice and clear. I get these ones every 4 months.