The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Image guided medical and surgical procedures utilize patient images obtained prior to or during a medical procedure to guide a physician performing the procedure. Recent advances in imaging technology, especially in imaging technologies that produce highly-detailed, two, three, and four dimensional images, such as computed tomography (CT), magnetic resonance imaging (MRI), fluoroscopic imaging (such as with a C-arm device), positron emission tomography (PET), and ultrasound imaging (US) has increased the interest in image guided medical procedures.
Typical image guided navigation systems require dynamic reference frames to track the position of the patient should patient movement occur during the assisted procedure. The dynamic reference frame (DRF) is generally affixed to the patient in a generally permanent or immovable fashion. The DRF can include a tracking device that has multiple markers that are trackable by the navigation or tracking system. In addition, many navigation systems generally employ a tracking device having multiple markers coupled to an instrument or the imaging device to enable the instrument or imaging device to be tracked.
In order to properly track the navigated instrument, imaging device and, optionally, track the position of the patient through the DRF, the instrument, the imaging device and the DRF must be distinguishable at all orientations by the navigation or tracking system. Generally, in order to ensure the instrument, the imaging device and the DRF are viewable at all orientations for an optical tracking system, the instrument, the imaging device and the DRF can each include a tracking device that employs multiple markers. Each marker can typically include a light emitting or light reflecting object. The tracking device also includes multiple faces, with each face distinguishable at all orientations. For each face of the tracking device, the light emitting or light reflecting objects can be arranged in a unique pattern such that each face of the tracking device has an easily identifiable signature pattern of light emitting or light reflecting objects.
Typically, to form the unique pattern of the light emitting or light reflecting objects, each light emitting or light reflecting object on the particular face is spaced a unique distance away from each of the other light emitting or light reflecting objects on that face. Thus, as the number of faces on the tracking device increases, in order to form the unique pattern of light emitting or light reflecting objects, the light emitting or light reflecting objects must be spaced further and further apart. This increased spacing of the light emitting or light reflecting objects on the faces to form a unique pattern for each face causes the size of the faces on the tracking device to increase, which can be undesirable when using multiple faced tracking device to navigate size or weight-constrained devices. Accordingly, it can be desirable to provide a system and method for tracking positions of tracking devices that utilize uniform marker geometries, such as light emitting or light reflecting objects.