High-resolution optical coherence tomography-guided laser ablation of surgical tissue

Background. Optical coherence tomography (OCT) is a compact high-speed imag ing technology which uses infrared light to acquire cross-sectional images of tissue on the micrometer scale. Because OCT images are based on the opti cal backscattering properties of tissue, changes in tissue optical properti es due to surgical laser ablation should be detectable using this technique . In this work, we examine the feasibility of using real-time OCT imaging t o guide the placement and observe the dynamics of surgical laser ablation i n a variety of tissue types. Materials and methods. More than 65 sites on five ex vivo rat organ tissue types were imaged at eight frames per second before, during, and after lase r ablation, Ablation was performed with a coincident continuous wave argon laser operating at 514-nm wavelength and varying exposure powers and durati ons, Following imaging, tissue registration was achieved using microinjecti ons of dye followed by routine histologic processing to confirm the morphol ogy of the ablation site. Results. High-speed OCT imaging at eight frames per second permitted rapid tissue orientation and guided ablation in numerous organ specimens. Acquisi tion rates were fast enough to capture dynamic changes in optical backscatt er which corresponded to thermal tissue damage during laser ablation, Conclusions. The ability of high-resolution highspeed OCT to guide laser ab lation and image the dynamic changes suggests a role in image-guided surgic al procedures, such as the ablation of neoplasms. Future in vivo studies ar e necessary to demonstrate performance intraoperatively. (C) 1999 Academic Press.