Available range analysis of laser guidance system and its application to monolithic integration with optical tracker Y. Nakajima a, * , H. Yamamoto a , Y. Sato a , N. Sugano b , Y. Momoi c , T. Sasama d , T. Koyama e , Y. Tamura f , K. Yonenobu f , I. Sakuma g , H. Yoshikawa b , T. Ochi e,h , S. Tamura a a Div. of Interdisciplinary Image Analysis, Graduate School of Medicine, Osaka University, Osaka, Japan b Dept. of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, Osaka, Japan c Hitachi Ltd., Tokyo, Japan d Department of Information and Knowledge Engineering, Faculty of Engineering, Tottori University, Tottori, Japan e Division of Robotic Therapy, Graduate School of Medicine, Osaka University, Osaka, Japan f Osaka Minami National Hospital, Osaka, Japan g Graduate School of Frontier Sciences, the University of Tokyo, Tokyo, Japan h National Sagamihara Hospital, Kanagawa, Japan Abstract. A laser guidance alignment procedure for linear surgical tools by directly drawing two laser-beam lines onto the cylindrical tool surface was presented in our previous papers. In this paper, we describe feasibility analysis of the laser guidance alignment procedure. The available range of tool orientation and entry position is clarified in which accurate guidance is guaranteed. Further, a monolithic integration of the laser devices with an optical tracker is designed using the result of available range analysis. By monolithic integration, usability of the system is expected to greatly improve since the monolithic integrated laser devices can be intraoperatively relocated without the calibration. The details of parameter tuning in the monolithic design were reported. D 2004 CARS and Elsevier B.V. All rights reserved. Keywords: Augmented realty device; Laser-beam projection; Surgical navigation; Linear tool alignment 1. Introduction Laser-beam projection systems of surgical guidance information have recently been developed, in which laser-beams are directly projected onto the surgical field so that the surgeon can obtain the guidance information without looking away from surgical field to see the computer monitor [1–3]. In Refs. [1,2], a special procedure for alignment of linear 0531-5131/ D 2004 CARS and Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2004.03.127 * Corresponding author. Tel.: +81-6-6879-3564; fax: +81-6-6879-3569. E-mail address: nakajima@image.med.osaka-u.ac.jp (Y. Nakajima). www.ics-elsevier.com International Congress Series 1268 (2004) 449 – 454