Speaker
Description
Precise intraoperative localization of tumors and sentinel lymph nodes remains a major challenge in oncologic surgery. Radio-guided surgery (RGS), widely used in procedures such as sentinel lymph node biopsy (SLNB) and radioguided occult lesion localization (ROLL), relies on the detection of radiotracers ( most commonly $^{99m}$Tc ) accumulated in metabolically active tissues. Despite its clinical success, the standard instrumentation used during surgery remains handheld gamma probes, which provide only acoustic feedback and limited spatial information. The absence of direct imaging can lead to prolonged localization time, increased invasiveness, and strong dependence on operator experience.
To overcome these limitations, we developed POSICS, a compact handheld gamma camera designed for real-time intraoperative imaging. The system employs position-sensitive silicon photomultipliers (LG-SiPMs) to achieve high-precision gamma detection in a lightweight and fully wireless device weighing approximately 350–400 g. Its ergonomic design allows seamless integration into the surgical workflow while providing direct imaging capability within the operating room.
Unlike conventional probes, POSICS provides real-time visual imaging of radiolabeled tissues, allowing surgeons to identify activity hotspots and verify lesion removal directly during the procedure. Performance characterization demonstrates millimetric spatial resolution, reaching approximately 1.4 mm at contact, with sensitivities up to 481 cps/MBq depending on the collimator configuration. These performance levels enable precise detection of tumors and sentinel lymph nodes while maintaining the portability required for intraoperative use.
A major advantage of the system is the speed of image acquisition. Preclinical trials have shown that radiolabeled tumors can be localized within seconds, achieving imaging precision comparable to that obtained with large nuclear medicine systems such as SPECT scanners, but without the long acquisition times or complex reconstruction procedures typically required. This rapid imaging capability enables continuous intraoperative feedback and supports faster surgical decision-making.
Beyond two-dimensional imaging, POSICS also enables three-dimensional reconstruction of radiotracer distributions. The feasibility of 3D reconstruction has already been demonstrated in laboratory studies and is currently being evaluated in ongoing preclinical trials. This capability aims to provide depth information on radiolabeled lesions relative to the surgical surface, potentially improving surgical navigation and margin assessment.
An additional innovation of the platform is the integration of Augmented Reality (AR) visualization. Gamma images can be spatially registered with the patient’s anatomy and projected through AR interfaces, enabling surgeons to visualize radioactive targets directly within the surgical field by wearing AR glasses. By combining precise gamma imaging with spatially registered visualization, POSICS transforms nuclear medicine data into an intuitive intraoperative navigation tool.
The technology is protected by a filed European patent, and the project has received significant recognition within the clinical innovation ecosystem, including the Innovation Prize from the Hôpitaux Universitaires de Genève (HUG).
By combining high-precision gamma imaging, rapid acquisition, emerging 3D capability, and augmented reality visualization, POSICS represents a new generation of intraoperative nuclear imaging systems aimed at enabling image-guided precision surgery and improving outcomes in cancer treatment.
| Presentation type | Oral |
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