Click-on fluorescence detectors: using robotic surgical instruments to characterize molecular tissue aspects.

Fluorescence imaging is increasingly being implemented in surgery. One of the drawbacks of its application is the need to switch back-and-forth between fluorescence- and white-light-imaging settings and not being able to dissect safely under fluorescence guidance. The aim of this study was to engineer 'click-on' fluorescence detectors that transform standard robotic instruments into molecular sensing devices that enable the surgeon to detect near-infrared (NIR) fluorescence in a white-light setting. This NIR-fluorescence detector setup was engineered to be press-fitted onto standard forceps instruments of the da Vinci robot. Following system characterization in a phantom setting (i.e., spectral properties, sensitivity and tissue signal attenuation), the performance with regard to different clinical indocyanine green (ICG) indications (e.g., angiography and lymphatic mapping) was determined via robotic surgery in pigs. To evaluate in-human applicability, the setup was also used for ICG-containing lymph node specimens from robotic prostate cancer surgery. The resulting Click-On device allowed for NIR ICG signal identification down to a concentration of 4.77 × 10-6 mg/ml. The fully assembled system could be introduced through the trocar and grasping, and movement abilities of the instrument were preserved. During surgery, the system allowed for the identification of blood vessels and assessment of vascularization (i.e., bowel, bladder and kidney), as well as localization of pelvic lymph nodes. During human specimen evaluation, it was able to distinguish sentinel from non-sentinel lymph nodes. With this introduction of a NIR-fluorescence Click-On sensing detector, a next step is made towards using surgical instruments in the characterization of molecular tissue aspects.

Extending the Hybrid Surgical Guidance Concept With Freehand Fluorescence Tomography.

Within image-guided surgery, 'hybrid' guidance technologies have been used to integrate the complementary features of radioactive guidance and fluorescence guidance. Here, we explore how the generation of a novel freehand fluorescence (fhFluo) imaging approach complements freehand SPECT (fhSPECT) in a hybrid setup. Near-infrared optical tracking was used to register the position and the orientation of a hybrid opto-nuclear detection probe while recording its readings. Dedicated look-up table models were used for 3D reconstruction. In phantom and excised tissue settings (i.e., flat-surface human skin explants), fhSPECT and fhFluo were investigated for image resolution and in-tissue signal penetration. Finally, the combined potential of these freehand technologies was evaluated on prostate and lymph node specimens of prostate cancer patients receiving prostatectomy and sentinel lymph node dissection (tracers: indocyanine green (ICG) +99m Tc-nanocolloid or ICG-99mTc-nanocolloid). After hardware and software integration, the hybrid setup created 3D nuclear and fluorescence tomography scans. The imaging resolution of fhFluo (1 mm) was superior to that of fhSPECT (6 mm). Fluorescence modalities were confined to a maximum depth of 0.5 cm, while nuclear modalities were usable at all evaluated depths (<2 cm). Both fhSPECT and fhFluo enabled augmented- and virtual-reality navigation toward segmented image hotspots, including relative hotspot quantification with an accuracy of 3.9% and 4.1%. Imaging in surgical specimens confirmed these trends (fhSPECT: in-depth detectability, low resolution, and fhFluo: superior resolution, superficial detectability). Overall, when radioactive and fluorescent tracer signatures are used, fhFluo has complementary value to fhSPECT. Combined the freehand technologies render a unique hybrid imaging and navigation modality.

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

PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: Overall the DROP-IN design proves to be a valuable tool for robot-assisted radioguided surgery approaches.

Revolutionizing (robot-assisted) laparoscopic gamma tracing using a drop-in gamma probe technology.

In complex (robot-assisted) laparoscopic radioguided surgery procedures, or when low activity lesions are located nearby a high activity background, the limited maneuverability of a laparoscopic gamma probe (LGP; 4 degrees of freedom (DOF)) may hinder lesion identification. We investigated a drop-in gamma probe (DIGP) technology to be inserted via a trocar, after which the laparoscopic surgical tool at hand can pick it up and maneuver it. Phantom experiments showed that distinguishing a low objective from a high background source (1:100 ratio) was only possible with the detector faced >90° from the high background source. Signal-low-objective-to-background ratios of 3.77, 2.01 and 1.84 were found for detector angles of 90°, 135° and 180°, respectively, whereas detector angles of 0° and 45° were unable to distinguish the sources. This underlines the critical role probe positioning plays. We then focused on engineering of the gripping part for optimal DIGP pick-up with a conventional laparoscopic forceps (4 DOF) or a robotic forceps (6 DOF). DIGPs with 0°, 45°, 90°, and 135° -grip orientations were designed, and their maneuverability- and scanning direction were evaluated and compared to a conventional LGP. The maneuverability- and scanning direction of the DIGP was found highest when using the robotic forceps, with the largest effective scanning direction range obtained with the 90° -grip design (0-180° versus 0-111°, 0-140°, and 37-180° for 0°, 45° and 135° -grip designs, respectively). For the laparoscopic forceps, the scan direction directly translated from the angle of the grip design with the advantage that the 135° -gripped DIGP could be faced backwards (not possible with the conventional LGP). In the ex vivo clinical setup, the surgeon rated DIGP pick-up most convenient for the 45°-grip design. Concluding, the DIGP technology was successfully introduced. Optimization of the grip design and grasping angle of the DIGP increased its utility for (robot-assisted) laparoscopic gamma tracing.

First Robotic SPECT for Minimally Invasive Sentinel Lymph Node Mapping.

In this paper we present the usage of a drop-in gamma probe for intra-operative Single-Photon Emission Computed Tomography (SPECT) imaging in the scope of minimally invasive robot-assisted interventions. The probe is designed to be inserted and reside inside the abdominal cavity during the intervention. It is grasped during the procedure using a robotic laparoscopic gripper enabling full six degrees of freedom handling by the surgeon. We demonstrate the first deployment of the tracked probe for intra-operative in-patient robotic SPECT enabling augmented-reality image guidance. The hybrid mechanical- and image-based in-patient probe tracking is shown to have an accuracy of 0.2 mm. The overall system performance is evaluated and tested with a phantom for gynecological sentinel lymph node interventions and compared to ground-truth data yielding a mean reconstruction accuracy of 0.67 mm.

First-in-human evaluation of a hybrid modality that allows combined radio- and (near-infrared) fluorescence tracing during surgery.

PURPOSE: The clinical introduction of the hybrid tracer indocyanine green (ICG)-(99m)Tc-nanocolloid, composed of a radioactive and a near-infrared (NIR) fluorescence component, has created the need for surgical (imaging) modalities that allow for simultaneous detection of both signals. This study describes the first-in-human use of a prototype opto-nuclear probe during sentinel node (SN) biopsy using ICG-(99m)Tc-nanocolloid. METHODS: To allow for fluorescence tracing, a derivative of the conventional gamma probe technology was generated in which two optical fibers were integrated to allow for excitation (785 nm) and emission signal collection (> 810 nm). The ability of this opto-nuclear probe to detect the fluorescence signal of the hybrid tracer ICG-(99m)Tc-nanocolloid was firstly determined ex vivo in (non)SNs samples obtained from 41 patients who underwent hybrid tracer-based SN biopsy in the head and neck or urogenital area. In an in vivo proof-of-concept study in nine of these 41 patients, SNs were localized using combined gamma and fluorescence tracing with the opto-nuclear probe. Fluorescence tracing was performed in a similar manner as gamma tracing and under ambient light conditions. RESULTS: Ex vivo, the gamma tracing option of the opto-nuclear probe correctly identified the SN in all 150 evaluated (non)SN samples. Ex vivo fluorescence tracing in the low-sensitivity mode correctly identified 71.7% of the samples. This increased to 98.9% when fluorescence tracing was performed in the high-sensitivity mode. In vivo fluorescence tracing (high-sensitivity mode) accurately identified the SNs in all nine patients (20 SNs evaluated; 100%). CONCLUSION: This study demonstrates the first-in-human evaluation of a hybrid modality capable of detecting both gamma and fluorescence signals during a surgical procedure. Fluorescence tracing could be performed in ambient light.

Sentinel lymph nodes fluorescence detection and imaging using Patent Blue V bound to human serum albumin.

Patent Blue V (PBV), a dye used clinically for sentinel lymph node detection, was mixed with human serum albumin (HSA). After binding to HSA, the fluorescence quantum yield increased from 5 × 10(-4) to 1.7 × 10(-2), which was enough to allow fluorescence detection and imaging of its distribution. A detection threshold, evaluated in scattering test objects, lower than 2.5 nmol × L(-1) was obtained, using a single-probe setup with a 5-mW incident light power. The detection sensitivity using a fluorescence imaging device was in the µmol × L(-1) range, with a noncooled CCD camera. Preclinical evaluation was performed on a rat model and permitted to observe inflamed nodes on all animals.

Sentinel lymph node detection by an optical method using scattered photons.

We present a new near infrared optical probe for the sentinel lymph node detection, based on the recording of scattered photons. A two wavelengths setup was developed to improve the detection threshold of an injected dye: the Patent Blue V dye. The method used consists in modulating each laser diode at a given frequency. A Fast Fourier Transform of the recorded signal separates both components. The signal amplitudes are used to compute relative Patent Blue V concentration. Results on the probe using phantoms model and small animal experimentation exhibit a sensitivity threshold of 3.2 µmol/L, which is thirty fold better than the eye visible threshold.

Paradoxical effect of severe dietary restriction on Long-Evans rat life span.

It has been firmly established that the longevity of 20- to 60%-calorie-restricted rodents, with malnutrition (essential nutrients deficiency) being avoided, is increased when compared to ad libitum fed rodents. However, the effects on life span of severe dietary restriction (i. e. malnutrition), with limited weight loss, remained unknown. The purpose of this 4-year study was to investigate the effects on longevity of a severe form of dietary restriction, with limited and controlled weight loss. To this end, a group of male Long-Evans rats severely dietary restricted (SDR group), with a weight loss throughout the experiment

(-)-9-Dehydrogalanthaminium bromide, a new cholinesterase inhibitor, enhances place and object recognition memory in young and old rats.

In a previous study, we showed that (-)-9-dehydrogalanthaminium bromide, a synthetic galanthamine derivative, was more potent than galanthamine in inhibiting acetylcholinesterase. We studied here the action of this new compound on recognition memory in young and old rats, using a two-trial recognition task designed to test both place and object recognition. (-)-9-dehydrogalanthaminium bromide was injected (0.3, 1, and 3 mg/kg, i.p.) in young and old rats before the acquisition phase, immediately after it, or before the retrieval phase of the task, in order to determine the stage of information processing affected by the compound. (-)-9-dehydrogalanthaminium bromide improved both place and object recognition in young rats, via an enhancement of acquisition (3 mg/kg: place recognition; 1 and 3 mg/kg: object recognition) and consolidation (1 and 3 mg/kg) information processing. In old rats, (-)-9-dehydrogalanthaminium bromide improved performance by acting on the acquisition processes of place (0.3, 1, and 3 mg/kg) and object (1 and 3 mg/kg) recognition. These results provide information on the profile of activity of (-)-9-dehydrogalanthaminium bromide on memory processes, and suggest that this new compound could have utility in the treatment of cognitive dysfunction occurring in Alzheimer's disease or in the normal course of aging.

Combined treatment with galanthaminium bromide, a new cholinesterase inhibitor, and RS 67333, a partial agonist of 5-HT4 receptors, enhances place and object recognition in young adult and old rats.

The present study was designed to investigate whether a combination of a new acetylcholinesterase inhibitor we have synthesized, galanthaminium bromide, and an agonist of 5-hydroxytryptamine(4) receptors, RS 67333, at doses ineffective alone, improves performance in tasks involving place and object recognition memory. Dose responses of each compound were determined in order to select doses without effect alone. Accordingly, young adult rats were injected intraperitoneally with galanthaminium bromide (0.3 mg/kg)+RS 67333 (0.01 mg/kg), and old rats with galanthaminium bromide (0.1 mg/kg for place and 0.3 mg/kg for object recognition)+RS 67333 (1 mg/kg). Drugs were injected before the acquisition phase, immediately after it, or before the retrieval phase to determine the stage of information processing affected by treatments. Doses of galanthaminium bromide and RS 67333, without effect on their own, jointly improved both place and object recognition in young adult rats via an enhancement of acquisition and consolidation information processing. In old rats, the combined treatment enhanced performance by acting on the acquisition processes of place recognition and on the acquisition and consolidation processes of object recognition. These results indicate that combining agents that act on different neuronal targets may be more powerful than either treatment alone, enabling use of lower doses of each compound, thereby attenuating the adverse effects of the individual drugs. A bitherapeutic strategy of this kind might thus be of interest in the treatment of the cognitive deficits related to "normal" or pathological aging.