Robot-assisted laparoscopic surgery using DROP-IN radioguidance: first-in-human translation

Radioguided surgery has been widely used for clinical procedures such as sentinel node resections. In the (robot-assisted) laparoscopic setting radioguidance is realized using laparoscopic gamma probes, which have limited maneuverability. To increase the rotational freedom, a tethered DROP-IN gamma probe was designed. Here we present the first in vivo feasibility study of this technology in prostate cancer patients.

Ten patients scheduled for a sentinel node procedure received four injections into the prostate with (indocyanine green-)^99mTechnetium-nanocolloid and underwent preoperative imaging (lymphoscintigraphy and SPECT/CT). The DROP-IN probe was inserted via the assistant port, still permitting the insertion and usage of additional laparoscopic tools.

The sentinel nodes were resected using the da Vinci® Si robot under guidance of DROP-IN gamma tracing and fluorescence imaging. The surgeon was able to independently maneuver the DROP-IN probe using the ProGrasp® forceps of the da Vinci® robot and distinguish sentinel nodes from background signal (such as the injection site).

Overall the DROP-IN design proves to be a valuable tool for robot-assisted radioguided surgery approaches.