An effective point-based registration tool for surgical navigation

Background: Surgical navigation assists in endoscopic surgeries by enabling surgeons to see concealed lesions and surrounding organs. Successful surgical navigation depends on accurate registration between a medical image and a patient. For accurate point-based registration, it is important to determine the matching order and positions of the markers correctly. It is particularly difficult to determine the order and positions when part of the markers cannot be located on the patient's body or when they cannot be identified in the images. Methods By using the automatic marker-matching option of the proposed tool, an optimum registration result can be obtained even with the partial loss of markers. In addition, this tool provides an intuitive marker selection interface that displays the registration error of each marker pair in different colors. Results The efficiency of the described tool in terms of the registration accuracy and time has been confirmed in more than 70 clinical applications. The fiducial registration errors were 1.28 ± 1.09 mm in ear, nose, and throat surgery and 3.55 ± 1.30 mm in liver tumor ablation therapy. Conclusions The proposed automatic matching scheme with marker selection interface was particularly effective where the markers were partly lost or incorrectly identified.