Disclosed is a soft tissue targeting complex of thorium-227 and a complexing agent, excluding a complex wherein said thorium-227 is: a) chelated by a derivative of 1,4,7,1 O-tetraazacyclododecane-1 ,4,7,10-tetraacetic acid and; b) conjugated to a targeting moiety with bioaffinity, excluding boneseekers, liposomes and folate conjugated antibodies or antibody fragments.