The purpose of this protocol is to demonstrate proof of concept and feasibility of new MRI or CT hardware, pulse sequences and data analysis software to plan and adapt radiotherapy treatment and to assess tumor response to radiotherapy (only FDA approved hardware are allowed in this study). Efforts to develop, modify and evaluate new or existing MR or CT imaging techniques must be a continuous practice with the goal of enhancing the use of MRI or CT during radiation therapy. The investigators therefore anticipate an ongoing need for such a protocol and believe the ability to perform such studies is critical to the translation of new imaging technologies from concept to routine clinical use. Under this protocol, modifications to the following items may be tested: pulse sequence programs, radiofrequency coils, reconstruction and processing software, other MR or CT system hardware and analysis software. A brief description of each of these items is described below. The potential risks associated with modifying each of these items, and the measures that will be taken to minimize these risks are described in subsequent sections.