"fluffy" spot on lung

I had 38 radiation treatments. Tomorrow I will have my 12th chemo treatment with one more series of three then I'm to go on Tarceva for 5 years. I had a port catheter put in three weeks ago and a "fluffy" spot showed up on my lung that was not there two months ago (looks like a very then cloud that you can see through). I had a CT scan and now there is a spot on the opposite lung that was not there three weeks ago. They are saying radiation damage or the cancer has matasticized. The original tumor has shrunk to less than 1/3 the original size. I can't believe the same type cancer would grow in one spot and shrink in another. Has anyone experienced a "fluffy" spot on any of their film?