Theranostics covers combination of diagnostic and therapeutic techniques for various cancers throughout body using suitable drug combination. This review covers well-known treatment of thyroid cancer and pheochromocytoma with I-131 compounds and also new radiopharmaceuticals for prostatic cancer and pancreatic cancer. Of particular, new trends toward patient outcome has been focused. A recent clinical study highlighted the ability of alpha-radiotherapy with high LET to overcome treatment resistance to beta--particle therapy. The theranostics will become an ever-increasing part of clinical nuclear medicine these days.