a biocompatible graft co - polymer adduct including a polymeric carrier , a protective chain linked to the polymeric carrier , a reporter group linked to the carrier or to the carrier and the protective chain , and a reversibly linked pt compound . the invention also relates to a method of treating a disease in a patient , particularly cancer , by administering to the patient a therapeutically effective amount of the adduct , and may include scanning the patient using an imaging technique which can provide a visible image of the distribution of the adduct .