Development of a non-blurring, dual-imaging tissue marker for gastrointestinal tumor localization

Knowing the exact location of gastrointestinal tumors both preoperatively and intraoperatively is essential for planning and performing laparoscopic surgery. Different techniques have been introduced to ascertain tumor locations during surgery, but none of these are fully satisfactory at establishing the minimum margins for organ resection while retaining curability. A new, non-blurring tissue marker, detectable by both X-ray computed tomography (CT) and near-infrared (NIR) fluorescence laparoscopy, has been developed, and we here examine its utility using an animal model.

Liposomes, comprised phospholipids and an NIR fluorescent dye (an indocyanine green derivative), and emulsions, consisting of phospholipids and oily radiographic contrast medium, were combined with polyglycerol-polyricinoleate to form giant cluster-like vesicles. This vesicular dispersion (300 μl) was administered into the porcine gastric submucosa using a gastroendoscope, and the detectability of the marker was examined using X-ray CT and NIR fluorescence laparoscopy.

One hour after the administration of the vesicular dispersion, X-ray CT identified four individual injection sites, each at a 1-cm radius of a metal hemostasis clip. NIR fluorescence laparoscopy detected individual fluorescent spots 18 hours after the administration of the vesicular dispersion.

We anticipate that this newly developed tissue marker will contribute to the preoperative simulation of laparoscopic gastrointestinal cancer surgery and its intraoperative navigation.