Tc-99m-Labeled Tricarbonyl His-CNA35 as an Imaging Agent for the Detection of Tumor Vasculature

Gilles Mees, Rudi Dierckx, Koen Mertens, Simon Vermeire, Magali Van Steenkiste, Chris Reutelingsperger, Yves D'Asseler, Kathelijne Peremans, Nancy Van Damme, Christophe Van de Wiele*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Given the importance of angiogenesis for a tumor's survival and growth, several therapeutic strategies rely on the selective inhibition of angiogenesis and the destruction of existing tumor vasculature. These strategies raise the need for a noninvasive tool to evaluate tumor vasculature. We describe the radiosynthesis and evaluation of an imaging tracer that specifically binds tumor subendothelial collagen and thereby images tumor vasculature. Methods: Tc-99m-tricarbonyl was prepared and labeled with His-collagen-binding adhesion protein 35 (CNA35). After in vitro specificity testing, in vivo biodistribution and dosimetric studies were performed in healthy nude mice via planar imaging. Tc-99m-(CO)(3) His-CNA35 was evaluated for in vivo imaging of tumor vasculature in a HT29 colorectal carcinoma xenograft. Results: The labeling procedure yielded a compound with 95%-99% radiochemical purity and good in vitro stability. An in vitro binding test confirmed specificity and functionality. Tc-99m-(CO)(3) His-CNA35 rapidly cleared from the blood and pre-dominantly accumulated in the kidneys and liver. The effective dose for a proposed single injection of 500 MBq of Tc-99m-(CO)(3) His-CNA35 is 3.70 mSv per organ or 2.01 mSv/g of tissue. Tumors were successfully visualized, and uptake correlated with ex vivo immunohistochemical staining of tumor vasculature. Conclusion: Tc-99m-(CO)(3) His-CNA35 may be a useful radioligand for the in vivo detection of tumor vasculature through subendothelial collagen binding. A noninvasive method of imaging tumor vasculature that could provide a reliable assessment of tumor vasculature would allow evaluation of the effectiveness of commonly used antiangiogenic therapies and determination of their optimal dosing and scheduling.
Original languageEnglish
Pages (from-to)464-471
JournalJournal of Nuclear Medicine
Issue number3
Publication statusPublished - 1 Mar 2012


  • CNA35
  • tricarbonyl
  • tumor vasculature
  • HT29

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