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Objective To compare the efficiency of 68Ga-labeled prostate-specific membrane antigen (68Ga-PSMA-11) and 18F-labeled sodium fluoride (18F-NaF) PET/CT in the diagnosis of bone metastasis in the patients with prostate cancer.Methods The prostate cancer patients suspected of bone metastasis who underwent 68Ga-PSMA-11 PET/CT and 18F-NaF PET/CT from January 2018 to January 2021 were included in this study.The number of lesions,maximum standardized uptake value (SUVmax),and tumor-to-background (T/B) ratio were compared between the two methods.Results 18F-NaF PET/CT detected more metastases than 68Ga-PSMA-11 PET/CT (310 vs.264,P<0.001).The median SUVmax[23.2 (16.4,33.4) vs.4.1 (2.5,5.6)] and median T/B ratio[7.0 (4.9,9.9) vs.6.7 (3.7,9.6)] of 18F-NaF PET/CT were higher than those of 68Ga-PSMA-11 PET/CT (all P<0.001).With the number of lesions as the indicator,the sensitivity,specificity,accuracy,positive predictive value,and negative predictive value of 18F-NaF PET/CT were 100.0%,92.0%,92.0%,98.7%,and 100.0% respectively,and those of 68Ga-PSMA-11 PET/CT were 85.2%,94.0%,79.2%,98.9%,and 50.5%,respectively.Conclusion 18F-NaF PET/CT is superior to 68Ga-PSMA-11 PET/CT in the detection of bone metastases of prostate cancer.
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Objective To investigate the causes of false-positive results in the 68Ga-labeled fibroblast activation protein inhibitor (68Ga-FAPI-04) PET/CT imaging. Methods The imaging data of 547 patients undergoing 68Ga-FAPI-04 PET/CT examination in the Department of Nuclear Medicine of the Affiliated Hospital of Southwest Medical University from September 2020 to May 2021 were retrospectively collected.Two experienced nuclear medicine diagnostic physicians analyzed the clinical data,relevant imaging examinations,laboratory examinations,pathological results and follow-up results of the patients with false-positive results. Results The 68Ga-FAPI-04 PET/CT imaging of 547 patients showed false-positive results in 99 (18.1%) patients,including 56 males and 43 females.The postoperative pathological examination confirmed false-positive results in 13 patients,including 1 patient of thyroiditis,2 patients of pulmonary tuberculosis,1 patient of bone tuberculosis,2 patients of pulmonary inflammatory pseudotumor,1 patient of pulmonary sarcoidosis,1 patient of pulmonary benign fibroma,1 patient of organic pneumonia,2 patients of renal angiomyolipoma,1 patient of mass pancreatitis,and 1 patient of pancreatic mucinous cystadenoma.The medical history,relevant imaging examination,and long-term follow-up confirmed false-positive results in 86 patients.Specifically,the false-positive uptake in the neck,chest,abdomen,bone joint,and skin occurred in 8 (9.3%),13 (15.1%),5 (5.8%),57 (66.3%),and 3 (3.5%) patients,respectively.Inflammation-related uptake appeared in 83 (83.8%) patients with false-positive imaging results,of which arthritis (23 patients) and osteophyte (29 patients) were the most common.Sixteen (16.2%) patients showed the false-positive uptake related to fibroblasts. Conclusion 68Ga-FAPI-04 PET/CT imaging will show non-malignant tumor false-positive results,which are mainly associated with inflammation and fibroblasts.