RecruitingPhase 1Drug trialImaging Study of [89Zr]DFO-YS5 for Detecting CD46 Positive Malignancy in Multiple MyelomaThis phase I trial tests the safety of \[89Zr\]DFO-YS5 positron emission tomography (PET) imaging and how well it works to detect CD46 positive cancer cells in patients with multiple myeloma. \[89Zr\]DFO-YS5 is an imaging agent called a radiopharmaceutical tracer. A radiopharmaceutical tracer uses a small amount of radioactive material that is injected into a vein to help image different areas of the body. \[89Zr\]DFO-YS5 targets a specialized protein called CD46, which is in certain multiple myeloma cancer cells, and \[89Zr\]DFO-YS5 PET scans may improve detection of multiple myeloma.