Feasibility of 99m Tc-MIP-1404 for SPECT/CT Imaging and Subsequent PSMA-Radioguided Surgery in Early Biochemically Recurrent Prostate Cancer: A Case Series of 9 Patients.

This case series evaluated the feasibility of prostate-specific membrane antigen (PSMA)-radioguided surgery (RGS) with ^99m Tc-MIP-1404 in recurrent prostate cancer. Methods: Nine patients with PSMA-positive lesions on PET/CT received ^99m Tc-MIP-1404 (median, 747 MBq; interquartile range [IQR], 710-764 MBq) 17.2 h (IQR, 16.9-17.5 h) before SPECT/CT and 22.3 h (IQR, 20.8-24.0 h) before RGS. Results: Seventeen PSMA-positive lesions were detected on PET/CT (median short-axis diameter, 4 mm; IQR, 3-6 mm; median SUV _max , 8.9; IQR, 5.2-12.6). Nine of 17 (52.9%) were visible on SPECT/CT (median SUV _max , 13.8; IQR, 8.0-17.9). Except for 2 foci, all PET/CT-positive findings demonstrated intraoperative count rates above the background level (median count, 31; IQR, 17-89) and were lymph node metastases. Moreover, PSMA-RGS identified 2 additional metastases compared with PET/CT. Prostate-specific antigen values decreased after RGS in 6 of 9 patients (67%). Conclusion: PSMA-RGS with ^99m Tc-MIP-1404 identified lymph node metastases in all patients, including 2 additional lesions compared with PET/CT.
(© 2023 by the Society of Nuclear Medicine and Molecular Imaging.)