Radiolabeled anti‐CD38 mAb (89Zr‐daratumumab) localization to osseous MM sites was visualized by PET with appreciable contrast by day 7.[19] In another clinical trial using 64Cu‐daratumumab, lesions that were 18F‐FDG negative but positive in CD38‐PET were found to be positive for MM involvement on biopsy,[42] indicating the potential for CD38‐PET for improved disease burden assessment. This evidence concerns the gene CD38 and Miyoshi myopathy.