Towards Intra-operative 3D Nuclear Imaging: Reconstruction of 3D Radioactive Distributions Using Tracked Gamma Probes

Abstract

Abstract. Nuclear medicine imaging modalities assist commonly in surgical guidance given their functional nature. However, when used in the operating room they present limitations. Pre-operative tomographic 3D imaging can only serve as a vague guidance intra-operatively, due to movement, deformation and changes in anatomy since the time of imaging, while standard intra-operative nuclear measurements are limited to 1D or (in some cases) 2D images with no depth information. To resolve this problem we propose the synchronized acquisition of position, orientation and readings of gamma probes intra-operatively to reconstruct a 3D activity volume. In contrast to conventional emission tomography, here, in a first proof-of-concept, the reconstruction succeeds without requiring symmetry in the positions and angles of acquisition, which allows greater flexibility. We present our results in phantom experiments for sentinel node lymph node localization. The results indicate that 3D intra-operative nuclear images can be generated in such a setup up to an accuracy equivalent to conventional SPECT systems. This technology has the potential to advance standard procedures towards intra-operative 3D nuclear imaging and offers a novel approach for robust and precise localization of functional information to facilitate less invasive, image-guided surgery.

EANM practice guidelines for lymphoscintigraphy and sentinel lymph node biopsy in melanoma

“…These enable fast and reliable detection and localization of SLNs [147,148]. Additionally, a 3D system has been developed [98,149] that allows the surgeon to visualize the SLN in real-time using 3D navigation. Both technical developments may simplify and speed up the SLNB procedure and also enable reliable detection of SLNs in anatomically complex regions such as the head and neck, where it is difficult to locate SLNs [97,99,102].…”

A Portable γ-Camera for Intraoperative Detection of Sentinel Nodes in the Head and Neck Region

“…This problem could be solved using a system with 2 separate detectors, although it would reduce the working space of the surgeon. Possibly in the future an integrated system that combines preoperative SPECT/CT images with intraoperative g-camera guidance will enable intraoperative 3-dimensional navigation (15). Additionally, if reliable tumor-specific radiotracers were to be developed, a portable g-camera could be able to guide excision of only the tumor-positive nodes (16).…”

Fusion of Freehand SPECT and Ultrasound to Perform Ultrasound-Guided Fine-Needle Aspiration Cytology of Sentinel Nodes in Head and Neck Cancer

“…On the basis of the integration of the acquired set of detector readouts and their position and orientation, the system is capable of generating 3D nuclear images similar to a SPECT image, thus providing visualization of the SN at any time. 8,9 Freehand SPECT can be integrated with video or other imaging modalities. 10 Recently, the fusion of these 3D nuclear images with US, making SN visualization on US possible, was introduced.…”