TECHNICAL FIELD

The present disclosure relates generally to operation of devices with articulated arms and more particularly to anatomical markers for use with articulated arms.

BACKGROUND

More and more devices are being replaced with autonomous and semi-autonomous electronic devices. This is especially true in the hospitals of today with large arrays of autonomous and semi-autonomous electronic devices being found in operating rooms, interventional suites, intensive care wards, emergency rooms, and the like. For example, glass and mercury thermometers are being replaced with electronic thermometers, intravenous drip lines now include electronic monitors and flow regulators, and traditional hand-held surgical instruments are being replaced by computer-assisted medical devices.

These electronic devices provide both advantages and challenges to the personnel operating them. Many of these electronic devices may be capable of autonomous or semi-autonomous motion of one or more articulated arms and/or end effectors. When the articulated arms and/or the end effectors include redundant degrees of freedom (i.e., more than the six degrees of freedom typically associated with Cartesian x, y, and z positioning and roll, pitch, and yaw orientations), the articulated arms and/or the end effectors may provide extensive flexibility in adjusting to changes in patient size, position, and/or orientation as the articulated arms and/or the end effectors are used to support medical procedures. This is possible because the redundant degrees of freedom allow the articulated arms and/or the end effectors to be positioned so as to avoid collisions among themselves, the patient, and/or other devices and personnel in an operating room and/or interventional suite.

Many medical procedures call for high precision in both the positioning and/or orientation of medical tools and/or devices. For example, medical procedures involving percutaneous ablation (including RF, cryo, microwave, and/or other forms of ablation), percutaneous needle biopsy, bone drilling, bone screw placement, seed planting, medicine delivery, high magnification imaging, micro surgery, and/or the like often call for very precise control of not only the position of a medical device attached to an articulated arm and/or end effector, but control over the orientation and/or movement of the medical device within a patient's anatomy.

Traditional approaches to the problem have relied on the trained eye and the skilled and steady hands of medical personnel operating a respective medical device. However, even the most skilled and steady of practitioners may not be able to ensure adequate placement and/or orientation of the medical device, especially when high precision and/or accuracy are desired. This may be further complicated when the placement and/or orientation of the medical device is actively adjusted in synchronization with a physiological motion of the patient such as the physiological motions associated with respiration, heart beats, and/or the like.

To aid in the placement and/or orientation of medical devices during a procedure, medical personnel often use pre-operative images, such as images obtained via computed tomography (CT), magnetic resonance imaging (MRI), and/or the like to review the anatomy of a patient and to plan procedures. However, because the pose of the patient during the pre-operative imaging may be different from the pose during the procedure due to changes in joint positions, orientation on a patient table, and/or the like, it may not be a simple procedure to translate or map the anatomy observed in the pre-operative images with the anatomy as presented during the procedure.

To help maintain correlations and/or registration between the pre-operative images (and the associated plan) and intra-operative images taken during the procedure, the medical personnel may use one or more markers attached to the patient's anatomy that may be used to identify specific points on the patient's anatomy that may be located in both the pre-operative and intra-operative images so as to help the medical personnel match the pre-operative plan to the actual procedure. These markers may be used by the medical personnel and/or motion planning systems to help guide the medical devices used during the procedure.

One type of marker that may be used is an external marker, which is typically affixed to an exterior portion of the patient's anatomy. External markers typically operate in the visual and/or infrared spectrum so that they may be observed directly by the medical personnel or indirectly using imaging devices such as cameras, endoscopes, microscopes, and/or the like. These external markers may be active or passive. Active external markers may include a light emitting diode (LED) or other emitter and/or an electromagnetic emitter. The LED may be visually observed, whereas the electromagnetic emitter typically uses an electromagnetic field pattern detector. Passive external markers may include a reflector with light reflected from an additional light source being detected. And while external markers improve the ability to identify specific locations on the patient's anatomy, the external markers have several limitations that impact their usefulness. First, the external markers are typically attached to the exterior anatomy of the patient, which may not be rigidly related to the anatomy that is the target of the procedure. External placement generally limits use of the external markers with soft tissues of the patient, which may undesirably move relative to the target of the procedure. Second, the light-based external markers are limited to line of sight applications. And while the electromagnetic emitters may operate without line of sight between the emitters and a detector, the detector may be limited due to interference between the electromagnetic fields omitted by the electromagnetic emitters and/or electromagnetic fields from other medical devices in the vicinity of the patient. In many cases, distortions in the electromagnetic field caused by ferromagnetic material used in other medical devices within the electromagnetic fields, may be another source of inaccuracy in electromagnetic tracking systems.

Accordingly, it would be advantageous to develop systems and methods for improved markers that may be used to identify locations on a patient's anatomy.

SUMMARY

Consistent with some embodiments, an anatomical marker includes a first material observable to a first imaging modality and a second material observable to a second imaging modality. The first material is different from the second material. The first imaging modality is different from the second imaging modality. The first and second imaging modalities obtain their images without using light in a visible spectrum.

Consistent with some embodiments, a method of controlling motion of a medical tool includes obtaining one or more first images using a first imaging modality, determining first coordinates of one or more anatomical markers relative to an anatomy of a patient based on content of the first images, obtaining one or more second images using a second imaging modality, determining second coordinates of the one or more anatomical markers relative to the medical tool based on content of the second images, and registering the medical tool to the anatomy of the patient based on the first and second coordinates.

Consistent with some embodiments, a computer-assisted medical device includes a control unit comprising one or more processors, a first articulated arm comprising one or more first joints, a second articulated arm comprising one or more second joints, a first imaging device mounted to a distal end of the first articulated arm, and a medical tool mounted to a distal end of the second articulated arm. The control unit obtains one or more first images from a second imaging device using a first imaging modality, determines first coordinates of one or more anatomical markers relative to an anatomy of a patient based on content of the first images, obtains one or more second images using a second imaging modality, determines second coordinates of the one or more anatomical markers relative to the medical tool based on content of the second images, and registers the medical tool to the anatomy of the patient based on the first and second coordinates and kinematic models of the first and second articulated arms.

Consistent with some embodiments, a non-transitory machine-readable medium includes a plurality of machine-readable instructions which when executed by one or more processors associated with a medical device are adapted to cause the one or more processors to perform a method. The method includes obtaining one or more first images using a first imaging modality, determining first coordinates of one or more anatomical markers relative to an anatomy of a patient based on content of the first images, obtaining one or more second images using a second imaging modality, determining second coordinates of the one or more anatomical markers relative to a medical tool coupled to the medical device based on content of the second images, and registering the medical tool to the anatomy of the patient based on the first and second coordinates.

