The purpose of the study is to test the safety and dosing of the study drug, [ 177Lu]Lu-FF58, a radioligand therapy for patients with various types of cancers. The study will also test the ability to identify tumor lesions using the new imaging agent, [68Ga]Ga-FF58, a radioligand imaging agent, and to see if it is safe. Radioligands are a type of cancer medicine in which a radioactive particle is attached to a compound (FF58 in this study). The compound circulates through the bloodstream, binds to proteins found on tumor lesions, and exposes those tumor lesions to radiation. FF58 can be...