? The overall objective of the proposed cooperative research and development project is the implementation and validation of an advanced instrument tracking technology to be used by the surgeon, the radiologist, the gastroenterologist, and other physicians to better enable image-guided cancer treatment, through these specific aims: ? Specific aim 1: Ascension Technology Corporation (ATC) has developed a fast and accurate DC magnetic position and orientation tracking device of 1-4 sensors with minimal occlusion, drift or distortion from conductive materials. A key feature is that the device may be implemented in a flat-plate transmitter configuration, which rests on the patient's bed and is unobtrusive while overcoming metal distortion effects. The device provides full six degrees-of-freedom tracking and connects to a host computer via a PCI bus. The deliverable of this specific aim will be a fully functioning tracking device in this flat transmitter configuration, suitable for non-human test and evaluation. ? Specific aim 2: MGH investigators will design applications in phantom and animal model systems to serve as the testbed for the novel tracking device. We will integrate the tracking device into a) a laparoscopic ultrasound system, and b) instruments used in ablative techniques (e.g. radio frequency ablation). ? Specific aim 3: A series of bench and animal experiments will be performed by the full team to assess the accuracy and behavior of the device in real operating room conditions. These experiments will establish the technical merit of the tracking device and the feasibility of the proposed medical applications. ? Specific aim 4: The system will be evaluated in light of Aim 3 results to determine changes required to meet feasibility goals and preparation for Phase II. Phase II will include a) performance of human studies using the laparoscopic ultrasound application, and b) preliminary evaluation of the tracking device in other promising applications, such as the novel """"""""gastric access"""""""" and the colonoscopic applications. ? ?