The main purpose of this study is to see if using proton beam radiation therapy instead of photon beam radiation therapy can reduce side effects from radiation treatment for rhabdomyosarcoma. Photon beam radiation is the standard type of radiation for treating most rhabdomyosarcoma and many other types of cancer. Photon beam radiation enters the body and passes through healthy tissue, encounters the tumor, then leaves the body through healthy tissue. A beam of proton radiation enters the body and passes through healthy tissue, encounters tumor, but then stops. This means that less healthy tissue is affected by proton beam radiation than by photon beam radiation.