A Preliminary Comparative Study Of ¹⁸F-PSMA-1007 And ¹⁸F-FDG PET/CT In The Evaluation Of Multiple Myeloma

Objective:¹⁸F-fluorodeoxyglucose（FDG）positron-emission tomography/computed tomography（PET/CT）can be used to evaluate multiple myeloma（MM）.However,bone lesions in some patients with MM showed negative uptake of FDG,which affected the evaluation of its efficacy.Prostate-specific membrane antigen（PSMA）can be expressed in tumor neovascularization endothelial cells,so this study aimed to evaluate the complementary value of ¹⁸F-PSMA-1007 PET/CT in MM.Methods:This study prospectively included patients with newly diagnosed or recurrent multiple myeloma confirmed by Clinical data and pathology from November 2021 to March 2023.All patients received ¹⁸F-PSMA-1007 and ¹⁸F-FDG PET/CT dual radiotracers imaging.The imaging results were independently analyzed by two experienced nuclear medicine doctors.The osteolytic lesions and soft tissue lesions detected by CT were studied.Finally,detection rate,maximum standardized uptake value(SUV_max)and tumor-to-background ratio（TBR）of lesions detected by the two radiotracers were compared.The lesions detection rates of two radiotracers were compared by Mc Nemar’s chi-square test.Wilcoxon signed-rank test was used to compare the SUV_max and TRB of lesions in two radiotracers.Results:A total of seventeen patients were included in this study,two patients were excluded because they received myeloma-related therapy during two PET/CT scans,and one patient was excluded because of an interval of more than one week between the two PET/CT imaging.Finally,a total of fourteen MM patients were included for analysis,including thirteen cases of active multiple myeloma and one case of smoldering multiple myeloma（SMM）.In the thirteen cases of active MM,a total of 226 osteolytic lesions and151 extramedullary lesions were detected.Among the osteolytic lesions,77.9%（176/226）lesions were detected by ¹⁸F-PSMA-1007 PET,while 51.3%（116/226）lesions were detected by ¹⁸F-FDG PET.The coincidence rate of osteolytic lesions detected by the two PET/CT imaging was 52.2%.¹⁸F-PSMA-1007 PET detected more osteolytic lesions than¹⁸F-FDG PET（P<0.001）.The SUV_max（median,4.1 vs 3.0,Z=-3.400,P=0.001）and TBR（median,2.3 vs 1.5,Z=-6.059,P<0.001）of osteolytic lesions were significantly higher in ¹⁸F-PSMA-1007 PET than in ¹⁸F-FDG PET.Among the extramedullary lesions,119 lesions were detected by ¹⁸F-PSMA-1007 PET with a median SUV_max of 4.7（range,2.1-16.2）,and 151 lesions were detected by ¹⁸F-FDG PET with a median SUV_max of 8.4（range,3.4-21.0）.Finally,the Durie-Salmon PLUS staging of four patients were upstaged by ¹⁸F-PSMA-1007 PET/CT.Intense diffuse bone marrow and focal bone uptake of ¹⁸F-PSMA-1007 PET and mild diffuse bone marrow uptake of ¹⁸F-FDG PET were observed in one patient with SMM.One patient with non-secretory MM who underwent a follow-up ¹⁸F-PSMA-1007 PET/CT scan after therapy showed an obvious treatment response compared with baseline ¹⁸F-PSMA-1007 PET/CT.Conclusions:Compared with ¹⁸F-FDG,¹⁸F-PSMA-1007 PET/CT had the added value in detecting osteolytic lesions.