Recently, a flexible DROP-IN gamma-probe was introduced for robot-assisted radioguided surgery, using traditional low-energy SPECT-isotopes. In parallel, a novel approach to achieve sensitive radioguidance using beta-emitting PET isotopes has been proposed. Integration of these two concepts would allow to exploit the use of PET tracers during robot-assisted tumor-receptor-targeted. In this study, we have engineered and validated the performance of a novel DROP-IN beta particle (DROP-INβ) detector.
Seven prostate cancer patients with PSMA-PET positive tumors received an additional intraoperative injection of ~ 70 MBq 68Ga-PSMA-11, followed by robot-assisted prostatectomy and extended pelvic lymph node dissection. The surgical specimens from these procedures were used to validate the performance of our DROP-INβ probe prototype, which merged a scintillating detector with a housing optimized for a 12-mm trocar and prograsp instruments.
After optimization of the detector and probe housing via Monte Carlo simulations, the resulting DROP-INβ probe prototype was tested in a robotic setting. In the ex vivo setting, the probe-positioned by the robot-was able to identify 68Ga-PSMA-11 containing hot-spots in the surgical specimens: signal-to-background (S/B) was > 5 when pathology confirmed that the tumor was located < 1 mm below the specimen surface. 68Ga-PSMA-11 containing (and PET positive) lymph nodes, as found in two patients, were also confirmed with the DROP-INβ probe (S/B > 3). The rotational freedom of the DROP-IN design and the ability to manipulate the probe with the prograsp tool allowed the surgeon to perform autonomous beta-tracing.
This study demonstrates the feasibility of beta-radioguided surgery in a robotic context by means of a DROP-INβ detector. When translated to an in vivo setting in the future, this technique could provide a valuable tool in detecting tumor remnants on the prostate surface and in confirmation of PSMA-PET positive lymph nodes.
EJNMMI research. 2020 Aug 06*** epublish ***
Francesco Collamati, Matthias N van Oosterom, Micol De Simoni, Riccardo Faccini, Marta Fischetti, Carlo Mancini Terracciano, Riccardo Mirabelli, Roberto Moretti, Judith Olde Heuvel, Elena Solfaroli Camillocci, Florian van Beurden, Henk G van der Poel, Renato A Valdes Olmos, Pim J van Leeuwen, Fijs W B van Leeuwen, Silvio Morganti
Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Piazzale Aldo Moro 2, 00185, Rome, Italy., Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333ZA, Leiden, The Netherlands., Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Piazzale Aldo Moro 2, 00185, Rome, Italy. ., Dipartimento di Fisica, Università di Roma Sapienza, Piazzale Aldo Moro 5, 00185, Rome, Italy., Department of Nuclear Medicine, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands., Department of Urology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Amsterdam, The Netherlands.