This invention provides methods for imaging and/or treating a tumor in a subject which comprise administering to the subject an amount of a radiolabeled antibody effective to image and/or treat the tumor, where the radiolabeled antibody binds to a cellular component released by dying tumor cells. This invention also provides methods for imaging and/or treating melanin-containing melanomas in a subject which comprise administering to the subject an amount of a radiolabeled anti-melanin antibody effective to image and/or treat the melanoma. The invention also provides compositions and methods of making compositions comprising radiolabeled antibodies for imaging and treating tumors, including melanin-containing melanomas.