Turning on the lights: new technologies in optical diagnostics and therapeutics.

WHETHER coupling a light source to the first cystoscope or using a laser as a bladeless scalpel, a surgeon’s ability to harness light for surgical guidance and intervention is among the most important modern surgical innovations. In recent years optical diagnostics, particularly fluorescence imaging techniques, have emerged as a potentially important adjunct to standard white light endoscopic and laparoscopic surgery. Similarly laser assisted surgery has been established as an alternative to standard electrosurgical resection during transurethral surgery. In this issue of The Journal 2 studies offer the latest examples of optical technologies used in surgical navigation and extirpative surgery. Iatrogenic ureteral injury is a rare but serious complication during abdominal and pelvic surgery. To reduce the risk, the urologist is frequently called on to place stents to facilitate intraoperative ureteral identification. While generally straightforward, ureteral stent placement is invasive and associated with potential morbidities. Noninvasive imaging of the ureters offers potential advantages compared to invasive placement of ureteral stents. In this issue of The Journal Verbeek et al (page 574) report on a feasibility study using near infrared (NIR) imaging for ureteral identification during open surgery. Low dose methylene blue, a drug familiar to urologists that is excreted in urine, served as the NIR dye detectable using a customized fluorescence camera brought in close proximity to the surgical field. Within 10 minutes after intravenous administration NIR fluorescence emanating from the methylene blue excreted in the urine was detectable along the length of the ureter in 10 patients undergoing open gynecologic surgery or radical cystectomy. This technology is an example of a rapidly emerging field of image guided surgery in which advanced optical imaging modalities are used to highlight and provide contrast between normal and diseased tissue. This application is reminiscent of fluorescence image guided renal surgery using another NIR dye, indocyanine green. The development of clinical imaging systems using previously approved drugs that