Recombinant Anti-FN1 x Anti-HSG Bispecific Antibody (scIgG) is designed to be expressed as two chains, each chain has the same units with their parental IgG antibodies, anti-FN1 and anti-HSG IgGs. The two chains form heterodimer via Fc KIH technology. This BsAb can be used in pretargeting system of PET, radioimaging or radiotherapy. It can mediate targeting of radioactivity to tumor cells. It is designed for the research of Solid tumors imaging and therapy.