Een prototype opto-nuclear probe voor gecombineerde radio- en fluroescentie geleide identificatie van de schildwachtklier(en)

Recent developments in the field of image-guided surgery have resulted in the introduction of fluorescent tracers into the clinic. For optical sentinel node identification, the near-infrared fluorescence tracer indocyanine green (ICG) was introduced. However, it does not allow for preoperative sentinel node mapping; the limited tissue penetration of the fluorescence signal prohibits this. With the introduction of a hybrid tracer, in which ICG is coupled to the conventional radiocolloid 99mTc-nanocolloid, our group showed that both preoperative sentinel node mapping and fluorescence sentinel node identification is possible with a single tracer.
To surgically detect the radioactive and the fluorescent signal, intraoperatively generally a gamma probe (detection radioactive signal) and a fluorescence camera (detection fluorescent signal) are used for sentinel node identification. To further improve these logistics, the company Eurorad developed a prototype opto-nuclear probe that is able to detect both the radioactive and the fluorescent signal. This way, it becomes possible to detect hybrid, combined radioactive and near-infrared fluorescent, tracers using a single imaging modality.

Intraoperative fluorescence tracing of the sentinel node using the opto-nuclear probe is feasible.

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According to the current standard, on the afternoon prior to, or on the morning of surgery, ICG-99mTc-nanocolloid will be injected peritumorally sub- or intracutaneously (patients with prostate cancer will be injected intraprostatically). Lymphoscintigrams and SPECT/CT imaging will be performed to determine the number and location of the sentinel node(s).

Sentinel node biopsy will be performed after general or regional anesthesia using the opto-nuclear probe. Firstly, sentinel nodes will be pursued via their radioactive signature. After localizing the sentinel node, the mode of the opto-nuclear probe will be switched to the fluorescence setting. Thereafter, fluorescence tracing to the sentinel node will be performed. After localization using the opto-nuclear probe, the conventional methods (gamma camera and fluorescence camera) will be used to evaluate the accuracy.

For each removed sentinel node, the gamma probe status (amount of radioactivity in the node) and the fluorescence status (amount of fluorescence in the node) will be documented. Sentinel nodes will be assessed following the standard sentinel node protocol at the pathology department.