Direct comparison of 99mTc-PSMA SPECT/CT and 68Ga-PSMA PET/CT in patients with prostate cancer

摘要

Objective(s): sup99m/supTc-PSMA SPECT/CT is a cost effective alternative for sup68/supGa-PSMA PET/CT. The aim of this study was to directly compare these two techniques in patients with prostate cancer. Methods: 28 man with prostate cancer were studied using sup99m/supTc-PSMA SPECT/CT and sup68/supGa-PSMA PET/CT in a short time period (68Ga-PSMA. sup99m/supTc-PSMA kit (PSMA I+S) was used for SPECT/CT and whole body imaging was performed 4 hours after IV injection of 740 MBq of sup99m/supTc-PSMA. Images were interpreted independently and the results of each imaging were recorded. R esults : The mean age of the patients was 64.7±9.6 years old and the mean time difference between two sets of images was 16.6±13.5 days. Abnormal uptake was seen in 25 (89.2%) patients by sup68/supGa-PSMA PET/CT and 20 (71.4%) patients with sup99m/supTc-PSMA SPECT/CT. No patients with positive sup99m/supTc-PSMA SPECT/CT had negative sup68/supGa-PSMA PET/CT. The mean number of detected lesions was 26.07±27.5 by sup68/supGa-PSMA PET/CT and 10.52±10.99 by sup99m/supTc-PSMA SPECT/CT (P0.001). Detection of lymph nodes and bone metastases were not significantly different between two sets of imaging (P0.05), however sup68/supGa-PSMA PET/CT were more successful in detection of prostate bed lesions compared to sup99m/supTc-PSMA scan. Interestingly, no patient with PSA level of 2.1 ng/ml had discordant result between two sets of images. Conclusion: sup99m/supTc-PSMA SPECT/CT is as accurate as sup68/supGa-PSMA PET/CT in M staging, however sup68/supGa-PSMA PET/CT detected more lesions compared to sup99m/supTc-PSMA SPECT/CT. Detection rate was not significantly different between two techniques in patients with PSA levels2.1 ng/ml.