The light spots are showing the parts of your bone that is weak, possibly bone loss. I know this because I had lots of x-rays taken about a year ago and I had light spots that showed up as well. I'm surprised they didn't explain to you what it could mean...that was the first thing they did when showing me the x-rays. Now, I don't know about in your case...but in my case the light spots meant Osteopenia. Yours could mean that or Osteoporosis or Arthritis. You should ask them to explain it to you. I'd just call ans ask. Good Luck!