Inside-Out Tracking for Flexible Hand-held Nuclear Tomographic Imaging

Tracking systems are used in many medical scenarios for the localization of devices or the patient, for example in intra-operative nuclear imaging. The infrared tracking system commonly used for this purpose is outside-in and often suffers from line of sight issues. To alleviate these, we present the combination of an inside-out tracking technique with a hand-held mini gamma camera and an image reconstruction pipeline to provide 3D SPECT-like images in a compact flexible setup suitable for interventions. As a proof-of-concept we show first results on phantoms mimicking common nuclear medicine procedures, sentinel lymph node biopsy in thyroid and breast cancer. Additionally, we show a first clinical result of this procedure on a breast cancer patient. The results achieved show comparable performance to the standard outsidein tracking approach, while easing the interventional procedure in terms of hardware and line of sight requirements.