The applicants propose to develop a system of computer software and hardware broadly applicable to problems of stereotaxic neurosurgery. The workstation would provide the surgeon with easy access to a variety of image modalities (e.g. CT, MRI, MRA and PET) to optimize stereostaxic procedures. In contrast to existing systems, the workstation would easily integrate these multi-modality image sets in a common coordinate system, and, through an intuitive and powerful user interface, provide for visualization of the data in a variety of two-and three-dimensional formats. The surgeon's ability to readily plan and inspect several surgical approaches in the context of this rich data set will greatly increase the accuracy and efficiency of the stereotaxic process. By the end of Phase II, the following goals will have been achieved: 1) Hardware Integration, 2) Implementation of Program Environment, 3) Implementation of User Interface, 4) Development of Visualization Tools, 5) Multi-Modality Coregistration, 6) Stereotaxic Brachytherapy and Radiosurgery Capabilities, 7) Documentation, 8) Adjustable Imaging Adapter Design and Phototyping, 9) Accuracy Testing and verification. The proposed stereotaxic neurosurgical system is designed to narrow the gap between current medical imaging technologies and the tools which make these data useful.