With the increased use of focal radiation dose escalation for primary prostate cancer (PCa), accurate delineation of gross tumor volume (GTV) in prostate-specific membrane antigen PET (PSMA-PET) becomes crucial. Manual approaches are time-consuming and observer dependent. The purpose of this study was to create a deep learning model for the accurate delineation of the intraprostatic GTV in PSMA-PET.
A 3D U-Net was trained on 128 different 18F-PSMA-1007 PET images from three different institutions. Testing was done on 52 patients including one independent internal cohort (Freiburg: n=19) and three independent external cohorts (Dresden: n=14 18F-PSMA-1007, Boston: Massachusetts General Hospital (MGH): n=9 18F-DCFPyL-PSMA and Dana-Farber Cancer Institute (DFCI): n=10 68Ga-PSMA-11). Expert contours were generated in consensus using a validated technique. CNN predictions were compared to expert contours using Dice similarity coefficient (DSC). Co-registered whole-mount histology was used for the internal testing cohort to assess sensitivity/specificity.
Median DSCs were Freiburg: 0.82 (IQR: 0.73-0.88), Dresden: 0.71 (IQR: 0.53-0.75), MGH: 0.80 (IQR: 0.64-0.83) and DFCI: 0.80 (IQR: 0.67-0.84), respectively. Median sensitivity for CNN and expert contours were 0.88 (IQR: 0.68-0.97) and 0.85 (IQR: 0.75-0.88) (p=0.40), respectively. GTV volumes did not differ significantly (p>0.1 for all comparisons). Median specificity of 0.83 (IQR: 0.57-0.97) and 0.88 (IQR: 0.69-0.98) were observed for CNN and expert contours (p=0.014), respectively. CNN prediction took 3.81 seconds on average per patient.
The CNN was trained and tested on internal and external datasets as well as histopathology reference, achieving a fast GTV segmentation for three PSMA-PET tracers with high diagnostic accuracy comparable to manual experts.
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2023 Jun 30 [Epub ahead of print]
Julius C Holzschuh, Michael Mix, Juri Ruf, Tobias Hölscher, Jörg Kotzerke, Alexis Vrachimis, Paul Doolan, Harun Ilhan, Ioana M Marinescu, Simon K B Spohn, Tobias Fechter, Dejan Kuhn, Peter Bronsert, Christian Gratzke, Radu Grosu, Sophia C Kamran, Pedram Heidari, Thomas S C Ng, Arda Könik, Anca-Ligia Grosu, Constantinos Zamboglou
Department of Radiation Oncology, Medical Center - University of Freiburg, Freiburg, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany; Faculty of Computer Science, Karlsruhe Institute of Technology, Karlsruhe, Germany. Electronic address: ., Department of Nuclear Medicine, Medical Center - University of Freiburg, Freiburg, Germany., Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technical University Dresden, Dresden, Germany., Department of Nuclear Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Dresden, Germany., Department of Nuclear Medicine, German Oncology Center - University Hospital of the European University, Limassol, Cyprus., Department of Radiation Oncology, German Oncology Center - University Hospital of the European University, Limassol, Cyprus., Department of Nuclear Medicine, University Hospital - Ludwig-Maximilians-Universität, Munich, Germany., Department of Radiation Oncology, Medical Center - University of Freiburg, Freiburg, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany., Department of Radiation Oncology, Medical Center - University of Freiburg, Freiburg, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany; Faculty of Medicine - University of Freiburg, Berta-Ottenstein-Programme, Freiburg, Germany., Department of Radiation Oncology, Medical Center - University of Freiburg, Freiburg, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany; Division of Medical Physics, Department of Radiation Oncology, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany., Department of Pathology, Medical Center - University of Freiburg, Freiburg, Germany., Department of Urology, Medical Center - University of Freiburg, Freiburg, Germany., Department of Computer Science, Technical University of Vienna, Vienna, Austria., Department of Radiation Oncology, Massachusetts General Hospital - Harvard Medical School, Boston, USA., Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital - Harvard Medical School, Department of Radiology, Boston, USA., Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital - Harvard Medical School, Department of Radiology, Boston, USA; Joint Program in Nuclear Medicine, Brigham and Women's Hospital - Harvard Medical School, Boston, USA; Department of Imaging, Dana-Farber Cancer Institute - Harvard Medical School, Boston, USA., Joint Program in Nuclear Medicine, Brigham and Women's Hospital - Harvard Medical School, Boston, USA; Department of Imaging, Dana-Farber Cancer Institute - Harvard Medical School, Boston, USA., Department of Radiation Oncology, Medical Center - University of Freiburg, Freiburg, Germany; German Oncology Center, European University of Cyprus, Limassol, Cyprus.