The labelling of Nanocoll® with [111In] for dual-isotope scanning

Visualization and biopsy of sentinel lymph nodes play an important role in planning and controlling the therapy of breast cancer. Hitherto two methods—scintigraphy or gamma probe detection after injection of [99mTc]-nanocolloids and visual detection after injection of patent blue dye—are used routinely. There are no conclusive publications elucidating such important parameters as injection site, injection method and colloidal parameters. The present work aims to label Nanocoll® with [111In] to provide an alternative method, a simultanous one-compound dual-isotope application. Methods: [111In]-Indiumchloride was buffered with acetate and transferred to the nanocolloid. The colloid labelling reaction was complete after 30 min and filtrated through 100 nm Nuclepore® filters. Results: Incorporation yield of [111In]-Indium into the nanocolloid was nearly quantitative, the step associated with the major loss of activity was the particle sizing with a mean yield of 55%. Conclusion: The presented method allows for the routine supply of [111In]-nanocolloids. Size-filtered [111In]-Nanocoll® shows the same particle size range as [99mTc]-Nanocoll®.