Reported examples of albumin-based imagingapproaches for potential patient stratification have been only oflimited success and thus novel tools like PET radiotracers for betterassessment and utilization of albumin-targeting drugs are needed.In this study, we successfully synthesized a well-defined and characterized 89Zr-labeled albumin imaging agent with excellent invitro and in vivo stability, enabling longitudinalPET imaging of subcutaneous tumor allografts in mice for up to 72h. The gene discussed is ALB; the disease is neoplasm.