The accurate and detailed knowledge of the changes (e.g., anatomically/biologically intra- and inter-fraction changes) to be obtained from this study would allow the research team to determine how Adaptive Radiation Therapy (ART) should be performed for a given tumor site/type. Radiation oncologists then can choose a proper ART strategy for a given tumor type to account for the anatomic/biological intra- and inter-fraction changes, improving accuracy of radiation therapy delivery, and in turn reducing treatment related toxicities and/or improving tumor local control.