Radiation Therapy to Treat Musculoskeletal Tumors

The study focuses on the following primary Objectives: * To estimate local control rates with image guided radiation therapy as defined in this study for patients with primary musculoskeletal tumors (MST). * Prospectively establish a baseline estimate of local control for patients with MST (Ewing's sarcoma family of tumors (ESFT), rhabdomyosarcoma (RMS) and non-rhabdomyosarcoma soft tissue sarcoma (STS)) treated with image guided radiation therapy. * Demonstrate that the increased level of conformality afforded by image guided radiation therapy does not reduce its efficacy relative to previously utilized non-image guided radiation therapy techniques in patients with Ewing's sarcoma family of tumors, resected soft tissue sarcomas, and group III rhabdomyosarcomas. * Assess local and regional patterns of failure for patients with MST treated with image guided radiation therapy relative to their targeted volumes. * Provide a long term (\>5 year) estimate of local disease control for patients with MST (Ewing's sarcoma family of tumors (ESFT)), rhabdomyosarcoma (RMS), and non-rhabdomyosarcoma soft tissue sarcoma (STS) treated with image guided radiation therapy. The study focuses on the following secondary objectives: * Establish a quantitative baseline estimate of radiation dose-related changes in normal tissues using novel objective measures of somatic change, musculoskeletal function, tissue biochemistry and physiology. o Investigate the dose and volume relationship for the developing physis and cortical bone using physical measures and imaging evaluations including: * Prospectively investigate whether an age based radiotherapeutic threshold of dose and volume that will induce premature physis closure and alter long bone length can be quantitatively identified. * Quantitatively explore the impact of radiation on cortical bone thinning and long bone curvature. * Relate radiation dose and volume to late (10+ year) alterations in bone integrity. * Describe the severity and time course of radiation-induced changes in the soft tissues including muscle. * Delineate sequential changes in muscular volume, muscle function and organ function (delineated by imaging and measures of physical function) following image guided radiation for specific muscular groups. * Correlate the temporal changes in muscular volume and function with changes in vascularity and metabolism defined by imaging studies.