RT Journal Article SR Electronic T1 Intraprostatic Tumor Segmentation on PSMA PET Images in Patients with Primary Prostate Cancer with a Convolutional Neural Network JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 823 OP 828 DO 10.2967/jnumed.120.254623 VO 62 IS 6 A1 Kostyszyn, Dejan A1 Fechter, Tobias A1 Bartl, Nico A1 Grosu, Anca L. A1 Gratzke, Christian A1 Sigle, August A1 Mix, Michael A1 Ruf, Juri A1 Fassbender, Thomas F. A1 Kiefer, Selina A1 Bettermann, Alisa S. A1 Nicolay, Nils H. A1 Spohn, Simon A1 Kramer, Maria U. A1 Bronsert, Peter A1 Guo, Hongqian A1 Qiu, Xuefeng A1 Wang, Feng A1 Henkenberens, Christoph A1 Werner, Rudolf A. A1 Baltas, Dimos A1 Meyer, Philipp T. A1 Derlin, Thorsten A1 Chen, Mengxia A1 Zamboglou, Constantinos YR 2021 UL http://jnm.snmjournals.org/content/62/6/823.abstract AB Accurate delineation of the intraprostatic gross tumor volume (GTV) is a prerequisite for treatment approaches in patients with primary prostate cancer (PCa). Prostate-specific membrane antigen PET (PSMA PET) may outperform MRI in GTV detection. However, visual GTV delineation underlies interobserver heterogeneity and is time consuming. The aim of this study was to develop a convolutional neural network (CNN) for automated segmentation of intraprostatic tumor (GTV-CNN) in PSMA PET. Methods: The CNN (3D U-Net) was trained on the 68Ga-PSMA PET images of 152 patients from 2 different institutions, and the training labels were generated manually using a validated technique. The CNN was tested on 2 independent internal (cohort 1: 68Ga-PSMA PET, n = 18 and cohort 2: 18F-PSMA PET, n = 19) and 1 external (cohort 3: 68Ga-PSMA PET, n = 20) test datasets. Accordance between manual contours and GTV-CNN was assessed with the Dice-Sørensen coefficient (DSC). Sensitivity and specificity were calculated for the 2 internal test datasets (cohort 1: n = 18, cohort 2: n = 11) using whole-mount histology. Results: The median DSCs for cohorts 1–3 were 0.84 (range: 0.32–0.95), 0.81 (range: 0.28–0.93), and 0.83 (range: 0.32–0.93), respectively. Sensitivities and specificities for the GTV-CNN were comparable with manual expert contours: 0.98 and 0.76 (cohort 1) and 1 and 0.57 (cohort 2), respectively. Computation time was around 6 s for a standard dataset. Conclusion: The application of a CNN for automated contouring of intraprostatic GTV in 68Ga-PSMA and 18F-PSMA PET images resulted in a high concordance with expert contours and in high sensitivities and specificities in comparison with histology as a reference. This robust, accurate and fast technique may be implemented for treatment concepts in primary prostate cancer. The trained model and the study’s source code are available in an open source repository.