Abstract
Objective: Intraoperative identification of positive resection margins (PRM) in high-risk prostate cancer (PC) needs improvement. Cerenkov Luminescence Imaging (CLI) with 68Ga-PSMA-11 is promising, however limited by low residual activity and artificial signals. Here, we aim to assess the value of CLI and flexible autoradiography (FAR) with 18F-PSMA-1007. Methods: Mice bearing subcutaneous PSMA-avid RM1-PGLS tumors were administered 18F-PSMA-1007 and PET/CT was performed. After sacrifice, organs were excised and measured signals in CLI and FAR-CLI were correlated with tracer activity concentrations (AC) obtained from PET/CT. For clinical assessment, seven high-risk PC patients underwent radical prostatectomy (RP) immediately after preoperative 18F-PSMA-PET/CT. Contrast-to-noise ratios (CNR) were calculated for both imaging modalities in intact specimen and after incision above the index lesion. Results: In the heterotopic in vivo mouse model (n = 5), CLI did not detect any lesion. FAR-CLI detected a distinct signal in all mice with a lowest AC of 7.25 kBq/ml (CNR: 5.48). After incision above the index lesion of the prostate specimen, no increased signal was observed at the cancer area in CLI. In contrast, using FAR-CLI a signal was detectable in 6 of 7 patients. AC in the missed index lesion was 1.85 kBq/ml, resulting in a detection limit of at least 2.06 kBq/ml. Histopathology demonstrated 2 PRM, none of which were predicted by CLI or FAR-CLI. Conclusion: 18F-PSMA FAR-CLI was superior to CLI in terms of tracer-related signal detectability. Visualization of PC was possible in RP down to 2.06 kBq/ml. However, the detection of PRM was limited. Direct anatomical correlation of FAR-CLI is challenging due to the scintillator overlay.
- Autoradiography
- Oncology: GU
- PET
- Cerenkov Luminescence Imaging
- Flexible Autoradiography
- Prostate cancer
- margin assessment
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