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.

[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.

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%.

The presented method allows for the routine supply of [111In]-nanocolloids. Size-filtered [111In]-Nanocoll shows the same particle size range as [99mTc]-Nanocoll.