Sure did; only the tumor in question was in my daughter's head. After a successful resection, the good folks at Yale and Sloan Kettering recommended the proton route for post-surgery radiation to ensure all the little cancer f--kers near the tumor were zapped. We read up on it and it seemed to make sense to target the beam instead of having it just plow through healthy brain tissue in a 2 year old. Of course, proton isn't available everywhere so we spent six weeks making a daily trip to the ProCure center in Central NJ.
To beat the ridiculous NJ traffic we'd get down there by 7am every morning with my daughter still in her PJs, running around the huge waiting room and entertaining the other patients -- who were all 60+ yo guys there for prostate treatment. So it certainly seems to be a popular option for that problem.
We gave the whole process very high marks and the result couldn't have gone better. 3 years later we're still looking clear.