title: An ultrasonic approach to localization of fiducial markers for interactive, image-guided neurosurgery--Part II: Implementation and automation.
abstract: Registration of image space and physical space lies at the heart of any interactive, image-guided neurosurgery system. This paper, in conjunction with the previous companion paper [1], describes a localization technique that enables bone-implanted fiducial markers to be used for the registration of these spaces. The nature of these subcutaneous markers allows for their long-term use for registration which is desirable for surgical follow-up, monitoring of therapy efficacy, and performing fractionated stereotactic radiosurgery. The major challenge to using implanted markers is determining the location of the markers in physical space after implantation. The A-mode ultrasonic technique described here is capable of determining the three-dimensional (3-D) location of small implanted cylindrical markers. Accuracy tests were conducted on a phantom representing a human head. The accuracy of the system was characterized by comparing the location of a marker analogue as determined with an optically tracked pointer and the location as determined with the ultrasonic localization. Analyzing the phantom in several orientations revealed a mean system accuracy of 0.5 mm with a +/- 0.1-mm 95% confidence interval. These tests indicate that transcutaneous localization of implanted fiducial markers is possible with a high degree of accuracy.
authors.affiliation: Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA. sschrein@wnec.edu
authors.forename: S
authors.initials: S
authors.lastname: Schreiner
authors.forename: R L
authors.initials: RL
authors.lastname: Galloway
authors.forename: J T
authors.initials: JT
authors.lastname: Lewis
authors.forename: W A
authors.initials: WA
authors.lastname: Bass
authors.forename: D M
authors.initials: DM
authors.lastname: Muratore
mesh_terms: D000465:Algorithms; D015415:Biomarkers; D002138:Calibration; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation; D009493:Neurosurgery / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D019736:Prostheses and Implants; D012016:Reference Values; D012535:Scalp / Q000000981:diagnostic imaging* / Q000601:surgery; D013238:Stereotaxic Techniques; D013813:Therapy, Computer-Assisted / Q000295:instrumentation; D014159:Transducers; D014463:Ultrasonography
chemical_list: D015415:Biomarkers