Robotically assisted stereotactic radiosurgery (SRS) uses bony landmarks, implanted metallic markers, or a custom-designed mask or vest containing optical markers to provide reference points for precise three-dimensional (3D) localization. With the aid of a computerized robotic system for one or more steps in the procedure, this approach enables precise targeting of radiation therapy, which minimizes the radiation dose to critical, healthy tissues near the target. Robotically assisted SRS has been introduced for a variety of thoracic and abdominal indications, including treatment of malignant tumors.