That is pretty much what I thought. I passed along this info to her and hopefully she'll make a full recovery.
The RAI will destroy any thyroid tissue that is left behind after surgery, and its certain that tissue will get left b/c its impossible to remove every little tissue cell.
They will also use the RAI in small doses to scan her body for any remaining cancer. If its still in any lymph nodes, they can see it on the scan and will follow up with surgery.
Hope everything goes well, I know its scary. I had papillary that spread to my lymph nodes as well and I am still kicking and breathing and cancer free so far :D