Ureter identifi cation using methylene blue and fluorescein

Abstract

The use of a multimodal optical system that expands the surgeons light spectrum of view can improve surgical performance making structures clearly visible during laparoscopic and open surgery. This allows for shorter procedural duration and improved prevention and incidence of ureteral injury associated with complex pelvic surgery. Optical imaging using invisible NIR fluorescent light has several advantages over currently available intraoperative techniques. First, visualization of the ureters does not require ionizing radiation, and uses only safe wavelengths of light for ample excitation. Secondly, because fluorescence emission is invisible to the human eye, the surgical field is not stained or changed in any way. The blue dyes that are currently used stain the surgical field and have relatively poor contrast. Thirdly, imaging can be performed in real-time (up to 15 frames per second) with the merged image from the color video and NIR fluorescent cameras providing anatomical landmarks that are easily identifiable. More work is needed to identify the optimal contrast agent and light wavelength with which it is most optimally visualized. Overall, this field of knowledge is of great interest and reports a great growing potential.