Tracking systems are used in many medical scenarios for the localization of the patient or of devices, for example in intra-operative nuclear imaging. The optical infrared tracking system commonly used for this purpose is outside-in and requires free line of sight between a camera and the tracked object, a distance that can reach several meters. To alleviate issues due to this requirement, we present an inside-out tracking approach where a video camera is attached to a hand-held mini gamma camera to provide combined activity and tracking information to reconstruct 3D SPECT-like images in a compact and flexible setup suitable for interventions. The radioactivity distribution is presented as an augmented reality overlay of the image of the video camera. We show results on phantoms mimicking common nuclear medicine procedures, such as the sentinel lymph node biopsy in thyroid and breast cancer. Distances between reconstructed hot spots differ less than 3% from the ground truth distances. We also show a first clinical images acquired on a breast cancer patient that show a 'correct' visualization substantiated by the physician's diagnosis. The tracking performance is comparable to the standard outside-in approach, while easing the interventional procedure in terms of a much easier and shorter setup as well as a substantial reduction of the line of sight requirements. This work significantly simplifies and reduces costs in a multitude of 3D nuclear image guided procedures.     «

Tracking systems are used in many medical scenarios for the localization of the patient or of devices, for example in intra-operative nuclear imaging. The optical infrared tracking system commonly used for this purpose is outside-in and requires free line of sight between a camera and the tracked object, a distance that can reach several meters. To alleviate issues due to this requirement, we present an inside-out tracking approach where a video camera is attached to a hand-held mini gamma camer...     »