title: Extra-luminal detection of assumed colonic tumor site by near-infrared laparoscopy.
abstract: Localization of colorectal tumors during laparoscopic surgery is generally performed by tattooing into the submucosal layer of the colon. However, faint and diffuse tattoos may lead to difficulties in recognizing cancer sites, resulting in inappropriate resection of the colon. We previously demonstrated that yttrium oxide nanoparticles doped with the rare earth ions (ytterbium and erbium) (YNP) showed strong near-infrared (NIR) emission under NIR excitation (1550 nm emission with 980 nm excitation). NIR light can penetrate deep tissues. In this study, we developed an NIR laparoscopy imaging system and demonstrated its use for accurate resection of the colon in swine.
  
  
  
  The NIR laparoscopy system consisted of an NIR laparoscope, NIR excitation laser diode, and an NIR camera. Endo-clips coated with YNP (NIR clip), silicon rubber including YNP (NIR silicon mass), and YNP solution (NIR ink) were prepared as test NIR markers. We used a swine model to detect an assumed colon cancer site using NIR laparoscopy, followed by laparoscopic resection. The NIR markers were fixed at an assumed cancer site within the colon by endoscopy. An NIR laparoscope was then introduced into the abdominal cavity through a laparoscopy port.
  
  
  
  NIR emission from the markers in the swine colon was successfully recognized using the NIR laparoscopy imaging system. The position of the markers in the colon could be identified. Accurate resection of the colon was performed successfully by laparoscopic surgery under NIR fluorescence guidance. The presence of the NIR markers within the extirpated colon was confirmed, indicating resection of the appropriate site.
  
  
  
  NIR laparoscopic surgery is useful for colorectal cancer site recognition and accurate resection using laparoscopic surgery.
authors.affiliation: Bioengineering Laboratory, RIKEN Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. zako@riken.jp.|Department of Chemistry and Biology, Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo, Matsuyama, 790-8577, Ehime, Japan. zako@riken.jp.
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Zako
authors.affiliation: Department of Colorectal Surgery, Surgical Technology Division, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan. maito@east.ncc.go.jp.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ito
authors.affiliation: Department of Material Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo, 125-8585, Japan.|Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hyodo
authors.affiliation: Bioengineering Laboratory, RIKEN Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.|Department of Material Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo, 125-8585, Japan.
authors.forename: Miya
authors.initials: M
authors.lastname: Yoshimoto
authors.affiliation: Department of Mechanical Engineering, Tokyo University of Science, Noda, Chiba, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Department of Mechanical Engineering, Tokyo University of Science, Noda, Chiba, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takemura
authors.affiliation: Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan.|Graduate School of Medicine, University of the Ryukyus, Nakagami, Okinawa, Japan.
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Kishimoto
authors.affiliation: Department of Gastroenterology, Endoscopy Division, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kaneko
authors.affiliation: Department of Material Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo, 125-8585, Japan. mail@ksoga.com.
authors.forename: Kohei
authors.initials: K
authors.lastname: Soga
authors.affiliation: Bioengineering Laboratory, RIKEN Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.|Department of Material Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo, 125-8585, Japan.
authors.forename: Mizuo
authors.initials: M
authors.lastname: Maeda
mesh_terms: D000818:Animals; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery; D004871:Erbium; D005453:Fluorescence; D020706:Laparoscopes; D010535:Laparoscopy / Q000379:methods*; D019265:Spectroscopy, Near-Infrared; D013525:Surgical Instruments; D013552:Swine; D013653:Tattooing / Q000379:methods*; D015018:Ytterbium; D015019:Yttrium
chemical_list: D015019:Yttrium; D004871:Erbium; D015018:Ytterbium; C091417:yttria
keywords: Colorectal cancer; Laparoscopic surgery; Nanoparticles; Near-infrared (NIR) imaging