Needle-based biopsy and image-guided therapy are rapidly growing areas of cancer diagnosis and treatment. Their advantage is their minimally-invasive nature, but the resulting difficulty in targeting the area of interest is an established cause of treatment failure. The desire for more effective needle-based procedures has spurred immense interest in image guidance. Of the available imaging options, ultrasound is both cost-effective and safe. However, traditional B-mode imaging can make targeting of the needle challenging due to the need to simultaneously manage needle and probe, and to image both needle and the targeted area. As a result, effective use of ultrasound guidance depends on a high level of clinician training and experience. Recently developed navigation systems attempt to provide targeting guidance. Unfortunately, these systems suffer from a number of drawbacks, including high cost, low usability, and limited accuracy, all of which greatly impede their effectiveness and wide adoption in practice. The Clear Guide Medical project will improve clinical practice by providing a cost-effective, accurate, and ergonomic approach to ultrasound image guidance. Key to this approach is the development of a compact guidance platform that attaches directly to the ultrasound probe. Through a unique combination of hardware and software components, Clear Guide Fusion will register the probe to the body and the target, will track needle-based interventional instruments, and will provide intuitive navigation information directly in situ that will guide a clinician towards targets that are available either in the ultraound image itself or in a preoperative patient scan. This technology will be available as a snap-on bracket for handheld ultrasound probes, and hence will eliminate the intrusiveness of current tracking systems and the attendant requirements including ensuring proper system calibration and the sterility of interventional tools. Our compact device will provide real time tracking of th patient surface and any needle or interventional tool, thus supporting in-situ visual guidance to the clinician without changes to the typical workflow, additional complex hardware, or additional preparation to ensure sterility. As a result, targeting accuracy will be improved, time will be reduced, and the level of clinical expertise needed for effective diagnosis or treatment will decrease. The system will be developed as a clinical prototype, and validated in a live animal study to account for probe and needle motions, as well as for breathing motion and tissue interaction and deformation. In summary, the significance of the Clear Guide Medical project is to improve both the diagnosis and the treatment of cancer by simplifying the targeting of cancer lesions for biopsy and treatment. The impact will be reduced cost and wider access to guidance technology making diagnostic interventions possible in more hospitals. PUBLIC HEALTH RELEVANCE: Our project entitled Clear Guide Fusion: In-Situ Guidance for Ultrasound-Guided Needle-Based Interventions will develop a device that will contribute to the treatment of cancer by improving the accuracy of needle placement for diagnosis or therapy. Our system will be the first that can be integrated directly to the the ultrasound probe-head, and will provide a more cost-effective and easy-to-use system than any competing system currently available.