New devices in radioguided surgery

Molecular imaging technologies are increasingly used not only to diagnose, monitor and guide cancer treatment, but also to intraoperatively identify disease. Radioguided surgery (RGS), one of the earliest and still most used forms of interventional molecular imaging, allows selective resection of tissues previously marked with a radiotracer (molecular targeted image-guided surgery). Classical applications, using handheld probes or portable devices, range from implanted radioactive seeds to detection of local administered radiotracer deposits in either the tumor or sentinel lymph nodes. There are, however, specific restrictions and limitations, but also great potentials, requiring refurbishment or improvement of these conventional devices. This narrative review provides an overview of the diversity of technologies available in the conventional and more advanced uses of RGS, such as robotic laparoscopic surgery and the newest issues to be potentially implemented toward full integration of radioguidance and hybrid guidance modalities. Surgical planning is enhanced by the information provided by presurgical scintigraphies with the aid of SPECT/CT and PET/CT, essential in those cases with a complex anatomical area, drainage or tracer distribution. Radioguidance modalities for low- to mid-energy gamma emitting tracers remain the most widely applied issues in RGS. PET probes have been available for over 20 years, but despite the high prevalence and clinical relevance of PET scanning, they have not found a routine place in RGS for cancer yet. β probes could help to precisely define clear tumor margin resection and could potentially support lesion detection in high background areas. New designs and technologies have been introduced such as flexible DROP-IN probes, Click-On probes and combined technologies (optical, bimodal devices) to improve radioguidance. A significant growth in RGS has been observed during the last 30 years. The appearance of new clinical demands, the introduction of robot-assisted procedures and the steps to modernize RGS equipment warrant the evolution and refinement of conventional devices to improve the detection in the era of precision medicine.