595758 A soft tissue targeting complex of thorium-227, wherein the thorium-227 is chelated by a derivative of 1,4,7,10-tetraazacyclodecane-l,4,7,l0-tetraacetic acid and the thorium-227 is conjugated to a targeting moiety with bioaffinity, excluding bone-seekers, liposomes and folate conjugated antibodies or antibody fragments.