Inclusion Criteria:  Male or female ≥ 21 years of age Histologically/immunohistochemistry-confirmed CD38-positive multiple myeloma At least one tumor lesion on CT, MRI, or FDG PET/CT within 90 days of protocol enrollment ECOG performance status 0 to 2 Written informed consent obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study  Exclusion Criteria:  Pregnant, breastfeeding, or unwilling to practice birth control during participation in the study. Life expectancy < 12 months Patients who cannot undergo PET/CT scanning because of weight limits. PET/CT scanners may not be able to function with patients over 450 pounds. History of anaphylactic reaction to humanized or human antibodies. Previous treatment with daratumumab. Previous treatment with other myeloma therapies will be allowed.