Fluorescence-Based Molecular Imaging of Porcine Urinary Bladder Sentinel Lymph Nodes.
The primary objective was to test the ability of a laparoscopic camera system to detect the fluorescent signal emanating from sentinel lymph nodes (SLNs) approximately 2 d after injection and imaging of a positron-emitting molecular imaging agent into the submucosa of the porcine urinary bladder.Methods:Three female pigs underwent a submucosal injection of the bladder with fluorescent-tagged tilmanocept, radiolabeled with both68Ga and99mTc. One hour after injection, a pelvic PET/CT scan was acquired for preoperative SLN mapping. Approximately 36 h later, robotic SLN mapping was performed using a fluorescence-capable camera system. After identification of the fluorescent lymph nodes, a pelvic lymph node dissection was completed with robotic assistance. All excised nodal packets (n= 36) were assayed for99mTc activity, which established a lymph node as an SLN.99mTc activity was also used to calculate the amount of dye within each lymph node.Results:All of the SLNs defined by the ex vivo γ-well assay of99mTc activity were detected by fluorescence mode imaging. The time between injection and robotic SLN mapping ranged from 32 to 38 h. A total of 5 fluorescent lymph nodes were detected; 2 pigs had 2 fluorescent lymph nodes and 1 pig exhibited a single lymph node. Four of the 5 SLNs exhibited increased SUVs of 12.4-139.0 obtained from PET/CT. The dye content of the injection sites ranged from 371 to 1,441 pmol, which represented 16.5%-64.1% of the injected dose; the amount of dye within the SLNs ranged from 8.5 to 88 pmol, which was equivalent to 0.38%-3.91% of the administered dose.Conclusion:Fluorescent-labeled68Ga-tilmanocept allows for PET imaging and real-time intraoperative detection of SLNs during robotic surgery.
Department of Urology, University of California, San Diego, La Jolla, California.
Hak J
HJ
Lee
Department of Radiology, University of California, San Diego, La Jolla, California; and.|UCSD Molecular Imaging Program, University of California, San Diego, La Jolla, California.
Christopher V
CV
Barback
Department of Radiology, University of California, San Diego, La Jolla, California; and.|UCSD Molecular Imaging Program, University of California, San Diego, La Jolla, California.
Carl K
CK
Hoh
Department of Radiology, University of California, San Diego, La Jolla, California; and.|UCSD Molecular Imaging Program, University of California, San Diego, La Jolla, California.
Zhengtao
Z
Qin
Department of Urology, University of California, San Diego, La Jolla, California.
Kareem
K
Kader
Department of Radiology, University of California, San Diego, La Jolla, California; and.|UCSD Molecular Imaging Program, University of California, San Diego, La Jolla, California.
David J
DJ
Hall
Department of Radiology, University of California, San Diego, La Jolla, California; and dvera@ucsd.edu.|UCSD Molecular Imaging Program, University of California, San Diego, La Jolla, California.
David R
DR
Vera
Department of Urology, University of California, San Diego, La Jolla, California.
Christopher J
CJ
Kane
D000818:Animals; D005240:Feasibility Studies; D005260:Female; D061848:Optical Imaging; D000072078:Positron Emission Tomography Computed Tomography; D000071036:Sentinel Lymph Node / Q000000981:diagnostic imaging*; D013552:Swine; D001743:Urinary Bladder / Q000000981:diagnostic imaging*
Lymphoseek; PET/CT; cystectomy; fluorescence; molecular imaging; pelvic lymph node dissection; robotic surgery; sentinel lymph node; tilmanocept