Evaluation of Surgical Margins with Intraoperative ex vivo PSMA-PET/CT

Ziel/Aim: Detection of positive resection margins in surgical procedures of locally advanced tumours is key for minimizing the risk of recurrence. This study aimed at evaluating the accuracy of intraprostatic functional tumour-volume segmentation in intraoperative ex vivo PSMA-PET/CT.

Methodik/Methods: Seven high-risk prostate cancer patients received [¹⁸F]F-PSMA-1007 prior to radical prostatectomy. After removal of the prostate gland, ex vivo imaging on the AURA 10 PET/CT system (XEOS, Ghent, Belgium) was performed and functional tumour volume was segmented using four semi-automatic segmentation methods. Resection margins and volumes were compared with histopathology. Additionally, a supportive phantom study was conducted to assess segmentation accuracy at low activity concentrations.

Ergebnisse/Results: 18 intraprostatic lesions were identified intraoperatively with ex vivo PET/CT. Sensitivity, specificity, positive and negative predictive value with regards to margin detection were up to 83%, 100%, 100%, and 92%, respectively (using an iterative thresholding method). Phantom deduced minimal segmentable activity concentration was approximately 2 kBq/mL. Based on our observations on lesion uptake, we recommend the administration of at least 2 MBq/kg and 0.4 MBq/kg [¹⁸F]F-PSMA-1007 for preoperative and intraoperative injections, respectively, to maintain reliable tumour-segmentation.

Schlussfolgerungen/Conclusions: Intraoperative ex vivo PSMA-PET/CT tumour segmentation is clinically feasible in high-uptake lesions. Further studies are needed to investigate the value of ex vivo PET/CT-based radioguided surgery in locally advanced tumours.

Publikationsverlauf

Artikel online veröffentlicht:
12. März 2025