A MINIATURIZED FLUORESCENCE IMAGING SYSTEM FOR OPTICAL-GUIDED SURGERY OF HUMAN LIVER METASTASES. A PRELIMINARY CLINICAL STUDY. Gabriele Barabino1, Jean-Guillaume Coutard2, Michel Berger2, Sylvain Gioux2, Véronique Josserand1, Michelle Keramidas1, Christian A. Righini1, Jean-Marc Dinten2 and Jean-Luc Coll1 1 INSERM-UJF U823, Institut Albert Bonniot, 38706 Grenoble, France ² CEA, LETI, MINATEC CAMPUS, 17 rue des martyrs 38054 Grenoble cedex 9, France Contact: [email protected], +33 476 539 553 Surgery is the only therapy that offers the possibility of cure for patients with hepatic metastatic diseases from colorectal or neuroendocrine carcinoma. Five-year survival rates after resection of all detectable liver metastases can reach 50%. In contrast, the role of hepatectomy in patients with liver metastases from noncolorectal and nonneuroendocrine carcinoma is not well defined. Scientific literature showed that in highly selected patients, resection of noncolorectal and nonneuroendocrine liver metastases can be done safely with survival similar to colorectal metastases. Therefore, preoperative and intraoperative staging are critical parameters in order to anticipate an optimized resectability and a favorable outcome. Indocyanine green (ICG) is a fluorescent agent approved in the clinic for liver function testing, as well as measurement of cardiac output and retinal angiography. It is a water-soluble, anionic, amphilic tricarbocyanine probe with a hydrodynamic diameter of 1.2 nm; the excitation and emission wavelengths in the presence of serum are 778 and 830 nm, respectively. Fluorescent navigation systems with ICG injection are used to detect sentinel lymph nodes. It has only recently shown real interest for optical-guided surgical oncology. Several studies report now that this technique can be useful for assisted intraoperative resection of otherwise undetectable liver cancers (such as hepatocellular and metastatic carcinomas) in patients who received and intravenous injection of ICG 4 to 7 days before surgery for a routine preoperative liver function test. We developed a new, miniaturized version of the Fluobeam (see www.fluoptics.com), which can be used for intra-operative surgery of cancer. We used this system and ICG in a clinical trial on 2 patients with liver metastasis, in order to demonstrate that ICG can efficiently label the rim of these tumors, when it is injected intravenously or infused ex-vivo on the surgical liver specimen. Furthermore, we discuss the quality of the ICG labeling, and the possibility to anticipate it by performing conventional diffusion-weighted magnetic resonance imaging, X-ray imaging and 18-FDG metabolic imaging of these patients before optical guided surgery.