Time-dependent accumulation of [89Zr]Zr-H4-Fc, [89Zr]Zr-H15-Fc and [89Zr]Zr-H17-Fc at FAP-expressing tumor sites was evident over the course of the 96-hour study, while tumor localization of [89Zr]Zr-NGS2405-Fc rapidly plateaued within 24-hours. The gene discussed is FAP; the disease is neoplasm.