Purpose: Imaging using positron emission tomography (PET) in the field of nuclear medicine is becoming increasingly important. The aim of this study was to develop a method for labeling of affibody molecules with radiocobalt for PET applications. Procedures: The human epidermal growth factor receptors type 2 (HER2) binding affibody molecule DOTA-Z2395-C was radiolabeled with 57Co (used as a surrogate of 55Co). The binding specificity and cellular processing of the labeled compound was studied in vitro followed by in vivo characterization in normal and tumor-bearing mice. Furthermore, a comparative biodistribution study was performed with a 111In-labeled counterpart. Results: DOTA-Z2395-C was successfully labeled with radiocobalt with nearly quantitative yield. The compound displayed good retention on cells over time and high tumor accumulation of radioactivity in animal studies. Imaging studies showed clear visualization of HER2-positive tumors. Furthermore, the radiocobalt label provided better tumor-to-organ ratios than 111In. Conclusions: Radiocobalt is a promising label for affibody molecules for future PET applications.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Cancer Research