Though I'm not expert and certainly not a doctor, I know that swelling is a big issue with CK and other radiation treatments.
Just an addendum to the comment Lisa has shared (thanks Lisa!) and no, I am no dr either but..... post-radiation edema/swelling
can (not always, but can) occur and radiation teams monitor closely via patient-related (verbalized) post-treat symptom and MRI's to see if it is occurring. If yes, usually/easily controlable with steroids (ie: Decadron, Prednisone, Medrol Dosepak, etc) to help keep it from occurring/enhancing.
Personally, I ran into enhanced symptoms post-CK between 3-9 mos possibly due to post-CK edema..... I reported this to my CK team (the key for all post-radiation patients... keeping their teams up to date and not brushing off anything that may be going on)... they put me on short term steroids and then, all was fine.
I can now report, pushing 6 yrs later, for me.... all is well. As we note here all the time, "individual results may vary."
Hope this helps.
Phyl