title: Intraoperative laparoscopic fluorescence guidance to the sentinel lymph node in prostate cancer patients: clinical proof of concept of an integrated functional imaging approach using a multimodal tracer.
abstract: BACKGROUND
  Integration of molecular imaging and in particular intraoperative image guidance is expected to improve the surgical accuracy of laparoscopic lymph node (LN) dissection.
  
  
  OBJECTIVE
  To show the applicability of combining preoperative, intraoperative, and postoperative sentinel node imaging using an integrated diagnostic approach based on an imaging agent that is both radioactive and fluorescent.
  
  
  METHODS
  Before surgery, multimodal indocyanine green (ICG)-(99m)Tc-NanoColl was injected into the prostate. Subsequent lymphoscintigraphy and single-photon emission computed tomography/computed tomography (SPECT/CT) imaging of pelvic nodes was performed to determine the location of the sentinel lymph nodes (SLNs) preoperatively. During the surgical procedure a fluorescence laparoscope, optimized for detection in the near infrared range, was used to visualize the nodes identified on SPECT/CT. Eleven patients scheduled for robot-assisted laparoscopic prostatectomy (RALP) with an increased risk of nodal metastasis, based on Memorial Sloan-Kettering Cancer Center/Kattan nomogram estimation, participated in a pilot assessment (N09IGF).
  
  
  METHODS
  Patients underwent RALP with LN dissection for prostate cancer.
  
  
  METHODS
  Radioactive and fluorescent signals were monitored using different modalities, and the correlation between the two types of signals was studied. The location of preoperatively detected SLNs was documented.
  
  
  CONCLUSIONS
  Preoperatively, SLNs were identified by SPECT/CT, and the multimodal nature of the imaging agent also enabled intraoperative detection via fluorescence imaging. Fluorescence particularly improved surgical guidance in areas with a high radioactive background signal such as the injection site. Ex vivo analysis revealed a strong correlation between the radioactive and fluorescent content in the excised LNs. Fluorescence detection is limited by the severe tissue attenuation of the signal. Therefore, radio guidance to the areas of interest is still desirable.
  
  
  CONCLUSIONS
  Initial data indicate that multimodal ICG-(99m)Tc-NanoColloid, in combination with a laparoscopic fluorescence laparoscope, can be used to facilitate and optimize dissection of SLNs during RALP procedures.
authors: Department of Urology, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands. h.vd.poel@nki.nl
authors: Henk G
authors: HG
authors: van der Poel
authors: Tessa
authors: T
authors: Buckle
authors: Oscar R
authors: OR
authors: Brouwer
authors: Renato A
authors: RA
authors: Valdés Olmos
authors: Fijs W B
authors: FW
authors: van Leeuwen
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000601:surgery; D005456:Fluorescent Dyes; D006801:Humans; D007208:Indocyanine Green; D010535:Laparoscopy / Q000379:methods*; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D064847:Multimodal Imaging / Q000379:methods; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D011849:Radioactive Tracers; D021701:Sentinel Lymph Node Biopsy / Q000379:methods; D013668:Technetium Tc 99m Aggregated Albumin; D014057:Tomography, X-Ray Computed
chemical_list: D005456:Fluorescent Dyes; D011849:Radioactive Tracers; D013668:Technetium Tc 99m Aggregated Albumin; C083602:technetium Tc 99m nanocolloid; D007208:Indocyanine Green