The invention is directed to bodies comprising an amorphous carbon particle on which are supported nanoparticles of an oxide of lanthanide. These bodies find use as a pharmaceutical for use in a surgery or therapy and diagnostic methods. The bodies can be made by a process comprising impregnating a carbon source material by contacting it with a solution of a salt of said lanthanide; drying said impregnated carbon source material; and subjecting said dried impregnated material to pyrolysis under inert conditions.本發明係有關於含有非晶碳粒子的物體,該非晶碳粒子承載鑭系氧化物奈米粒子。此物體可作為藥物使用於外科手術或治療及診斷方法中。此物體可以下列步驟製備,包括利用接觸碳源物質與鑭系鹽類溶液的方式浸漬此碳源物質,乾燥此經浸漬的碳源物質,且在惰性環境下熱分解此乾燥的浸漬物質。