Highlighting the difficulty for surgeons to localize and remove small pelvic lymph node detected by PSMA PET, a retrospective study evaluated PCa recurrence following primary surgery, and with a PSMA-PET performed before and after surgery, 15/33 patients (45%) had persistent lesions that were visible on PSMA PET/CT before surgery.1
Herein, we sought to supplement surgeons by providing personalized three-dimensional, virtually rendered (3D VR) images to be used in a peri-operative setting. In our manuscript, we describe the method to do this entirely for free with readily available software.
Figure 1: Using 3D Slicer a physicist or nuclear medicine physician segmented anatomy requested by the surgeon. The resulting segmentations were then saved as.OBJ and .MTL files to be uploaded into AutoDesk Viewer. This platform provided easy navigation and use for surgeons prior to, and during the surgical case.
Surgeons found the 3D VR models extremely helpful in localizing and resecting the target lesions. All target lesions in the study were successfully removed with the assistance of the 3D VR models. Surgeon feedback can be briefly summarized as follows:
R.R.: “Supplied models were used in peri-operative settings. The models provided a landmark of the location of the node(s), otherwise difficult to envision the exact location. It enabled the ability to place laparoscopic ports appropriately to gain initial exposure of the involved area, at which the gamma probe was used to concisely find the involved nodes.”
K.C.: “The 3D-VR model was so critical for surgery. The CT imaging was nowhere near as helpful as the 3-D model. It helped provide context so that we were able to focus the dissection to where the tumor was located.”
N.M.D.: “The 3D models provided me with significantly improved preoperative and intraoperative orientation as to where the involved lymph nodes were located in the pelvis and their relationship to other pelvic structures. This provided me more confidence before and during the operation that I was in fact looking in the correct areas of the pelvis.”
Below are two example patients who were included in the trial with the pre-surgery PSMA PET MIP, cross-sectional PET/CT images, and the 3D VR models.
Figure 2: Case 1 with single lymph node target lesion
Figure 3: Case 2 with three lymph node target lesions
While our 3D VR models were used for salvage pelvic lymph node dissection this methodology can be easily translated to other disciplines in need of careful strategic surgical planning. The preliminary results from this prospective exploratory trial can be found in a past publication by our group.2
Written by: Zachary Ells,1 Vinicius Ludwig,1 Adam B Weiner,2 Koichiro Kimura,1 Andrea Farolfi,3 Karim Chamie,4 Joseph Shirk,4 Nicholas M Donin,4 Robert Reiter,4 Johannes Czernin,1 Jeremie Calais,1 Magnus Dahlbom1
- Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, University of California Los Angeles UCLA, Los Angeles, CA, USA.
- Department of Urology, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
- Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, University of California Los Angeles UCLA, Los Angeles, CA, USA; Nuclear Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.
- Department of Urology, University of California Los Angeles, Los Angeles, CA, USA.
- A. Farolfi, A. Gafita, J. Calais, M. Eiber, A. Afshar-Oromieh, F. Spohn, F. Barbato, M. Weber, H. Ilhan, V. Cervati, A. Wetter, B. Hadaschik, A. Briganti, J. Walz, D. Pianori, S. Fanti, U. Haberkorn, K. Herrmann, W.P. Fendler, (68)Ga-PSMA-11 positron emission tomography detects residual prostate cancer after prostatectomy in a multicenter retrospective study, J. Urol. 202 (6) (2019) 1174–1181
- A.B. Weiner, Z. Ells, C. Meyer, M. Dahlbom, D. Sennung, D. Varughese, V. B. Ludwig, G. Carlucci, R. Grant, J. Czernin, J. Calais, R.E. Reiter, Clinical responses to prostate-specific membrane antigen radioguided salvage lymphadenectomy for prostate cancer recurrence: results from a prospective exploratory trial, Eur. Urol. Open Sci. 70 (2024) 36–42.