This study intends to employ 68Ga-NOTA-BCMA nanobody PET/CT imaging in patients with multiple myeloma to evaluate the feasibility of this technique for myeloma assessment, analyze the correlation between 68Ga-NOTA-BCMA nanobody uptake intensity and disease staging, tumor burden, and prognosis, explore its value in assessing treatment response and predicting early relapse, and compare its detection rate for myeloma lesions with that of 18F-FDG PET/CT. The results of this study may provide a more sensitive and specific imaging diagnostic method for patients with multiple myeloma and offer a basis for the individualized selection of future BCMA-targeted therapies. This study has been approved by the Ethics Committee of Peking Union Medical College Hospital.