⁸⁹Zr-nanocolloidal albumin-based PET/CT lymphoscintigraphy for sentinel node detection in head and neck cancer: Preclinical results

Identifying sentinel nodes near the primary tumor remains a problem in, for example, head and neck cancer because of the limited resolution of current lymphoscintigraphic imaging when using ^99mTc-nanocolloidal albumin. This study describes the development and evaluation of a nanocolloidal albumin-based tracer specifically dedicated for high-resolution PET detection. Methods: ⁸⁹Zr was coupled to nanocolloidal albumin via the bifunctional chelate p-isothiocyanatobenzyldesferrioxamine B. Quality control tests, including particle size measurements, and in vivo biodistribution and imaging experiments in a rabbit lymphogenic metastasis model were performed. Results: Coupling of ⁸⁹Zr to nanocolloidal albumin appeared to be efficient, resulting in a stable product with a radiochemical purity greater than 95%, without affecting the particle size. PET showed distinguished uptake of ⁸⁹Zr-nanocolloidal albumin in the sentinel nodes, with visualization of lymphatic vessels, and with a biodistribution comparable to ^99mTc-nanocolloidal albumin. Conclusion: ⁸⁹Zr- nanocolloidal albumin is a promising tracer for sentinel node detection by PET.