The introduction of the tethered DROP-IN gamma probe has enabled targeted robot-assisted radioguided prostate cancer (PCa) resection of pelvic sentinel lymph nodes (SLNs) and prostate-specific... Show moreThe introduction of the tethered DROP-IN gamma probe has enabled targeted robot-assisted radioguided prostate cancer (PCa) resection of pelvic sentinel lymph nodes (SLNs) and prostate-specific membrane antigen (PSMA)-positive lesions. While both procedures use Tc-99m-isotopes, the two vary in signal and background intensity. To understand how the different levels of image guidance impact surgical decision-making, computer-vision algorithms are used to extract the DROP-IN probe kinematic form clinical videos. 44 PCa patients undergo SLN (25) and PSMA-targeted (19) resections. PSMA-PET/CT and SPECT/CT create preoperative roadmaps, and intraoperative probe signal intensities are recorded. Using neural network-based software, probe trajectories are extracted from videos to extract multiparametric kinematics and generate decision-making and dexterity scores. PSMA-targeted resections yield significantly lower nodal signal intensities in preoperative SPECT-CT scans (three-fold; p = 0.01), intraoperative probe readouts (eight-fold; p < 0.001), and signal-to-background ratios (SBR; two-fold; p < 0.001). Kinematics assessment reveal that the challenges encounter during PSMA-targeted procedures converted to longer target identification times and increase in probe pick-ups (both five-fold; p < 0.001). This results in a fourfold reduction in the decision-making score (p < 0.001). Reduced signal intensities and intraoperative SBR values negatively affect the impact that image-guided surgery strategies have on the surgical decision-making process. Show less
Background: Robotic liver surgery represents the most recent evolution in the field of minimally-invasive liver surgery. For planning and guidance of liver resections, surgeons currently rely on... Show moreBackground: Robotic liver surgery represents the most recent evolution in the field of minimally-invasive liver surgery. For planning and guidance of liver resections, surgeons currently rely on preoperative 2-dimensional (2D) CT and/or MR imaging and intraoperative ultrasonography. Translating 2D images into digital 3-dimensional (3D) models may improve both preoperative planning and surgical guidance. The da Vinci (R) robotic surgical system is a platform suitable for the integration of multiple imaging modalities into one single view. In this study, we describe multimodal imaging options and introduce the Robotic Liver Surgery Cockpit; Methods: in-house developed software was used and validated for segmentation and registration to create a virtual reality 3D model of the liver based on preoperative imaging. The accuracy of the 3D models in the clinical setting was objectively assessed in 15 patients by measuring tumor diameters and subjectively with a postoperative conducted questionnaire; Results: Implementation and applicability of the 3D model in the surgical cockpit was feasible in all patients and the quality of the 3D reconstructions was high in 14 (93%) of cases. Tumor diameters measured on CT and/or MR imaging were comparable to automated measurements using the segmentation software and 3D models; Conclusions: the 3D model was successfully incorporated in the robotic surgery console as part of a multimodality imaging platform and aided the surgeon in planning and guidance of the resection. Future studies should focus on further automation of 3D rendering and progress into augmented reality. Show less
Kalisvaart, G.M.; Meijer, R.P.J.; Bijlstra, O.D.; Galema, H.A.; Steur, W.O. de; Hartgrink, H.H.; ... ; Hage, J.A. van der 2022
Simple Summary: Surgical resection plays a pivotal role in the treatment of GIST patients. The current study aims to explore the use of near-infrared fluorescence imaging to optimize the... Show moreSimple Summary: Surgical resection plays a pivotal role in the treatment of GIST patients. The current study aims to explore the use of near-infrared fluorescence imaging to optimize the intraoperative tumor identification of GISTs. For this purpose, the potential and limitations of the widely used, and non-specific, tracer indocyanine green were assessed in a multicenter study including 10 patients. Our results show that GISTs typically have similar fluorescence intensity to the surrounding tissue, within several minutes after the intravenous administration of indocyanine green. These findings justify future research into specific fluorescent tracers for GISTs, and set a reference for future intraoperative imaging trials. Background: Optimal intraoperative tumor identification of gastrointestinal stromal tumors (GISTs) is important for the quality of surgical resections. This study aims to assess the potential of near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) to improve intraoperative tumor identification. Methods: Ten GIST patients, planned to undergo resection, were included. During surgery, 10 mg of ICG was intravenously administered, and NIRF imaging was performed at 5, 10, and 15 min after the injection. The tumor fluorescence intensity was visually assessed, and tumor-to-background ratios (TBRs) were calculated for exophytic lesions. Results: Eleven GIST lesions were imaged. The fluorescence intensity of the tumor was visually synchronous and similar to the background in five lesions. In one lesion, the tumor fluorescence was more intense than in the surrounding tissue. Almost no fluorescence was observed in both the tumor and healthy peritoneal tissue in two patients with GIST lesions adjacent to the liver. In three GISTs without exophytic growth, no fluorescence of the tumor was observed. The median TBRs at 5, 10, and 15 min were 1.0 (0.4-1.2), 1.0 (0.5-1.9), and 0.9 (0.7-1.2), respectively. Conclusion: GISTs typically show similar fluorescence intensity to the surrounding tissue in NIRF imaging after intraoperative ICG administration. Therefore, intraoperatively administered ICG is currently not applicable for adequate tumor identification, and further research should focus on the development of tumor-specific fluorescent tracers for GISTs. Show less
Despite good sensitivity and a good negative predictive value, the implementation of sentinel node biopsy (SNB) in robot-assisted radical prostatectomy with extended pelvic lymph node dissection ... Show moreDespite good sensitivity and a good negative predictive value, the implementation of sentinel node biopsy (SNB) in robot-assisted radical prostatectomy with extended pelvic lymph node dissection (ePLND) for prostate cancer is still controversial. For this reason, we aimed to define the added value of SNB (with different tracer modalities) to ePLND in the identification of nodal metastases. Complication rates and oncologic outcomes were also assessed. Methods: From January 2006 to December 2019, prospectively collected data were retrospectively analyzed from a single-institution database regarding prostate cancer patients treated with robot-assisted radical prostatectomy and ePLND with or without additional use of SNB, either with the hybrid tracer indocyanine green (ICG)-Tc-99m-nanocolloid or with free ICG. Multivariable logistic and Cox regression models tested the impact of adding SNB (either with the hybrid tracer or with free ICG) on lymph nodal invasion detection, complications, and oncologic outcomes. Results: Overall, 1,680 patients were included in the final analysis: 1,168 (69.5%) in the non-SNB group, 161 (9.6%) in the ICG-SNB group, and 351 (20.9%) in the hybrid-SNB group. The hybrid-SNB group (odds ratio, 1.61; 95%CI, 1.18-2.20; P = 0.002) was an independent predictor of nodal involvement, whereas the ICG-SNB group did not reach independent predictor status when compared with the non-SNB group (odds ratio, 1.35; 95%CI, 0.89-2.03; P = 0.1). SNB techniques were not associated with higher rates of complications. Lastly, use of hybrid SNB was associated with lower rates of biochemical recurrence (0.79; 95%CI, 0.63-0.98) and of clinical recurrence (hazard ratio, 0.76, P = 0.035) than were seen in the non-SNB group. Conclusion: The implementation of hybrid-SNB technique with ICG-Tc-99m-nanocolloid in prostate cancer improves detection of positive nodes and potentially lowers recurrence rates with subsequent optimization of patient management, without harming patient safety. Show less
Azargoshasb, S.; Houwing, K.H.M.; Roos, P.R.; Leeuwen, S.I. van; Boonekamp, M.; Mazzone, E.; ... ; Oosterom, M.N. van 2021
With translation of the Drop-In gamma-probe, radioguidance has advanced into laparoscopic robot-assisted surgery. Global-positioning-system-like navigation can further enhance the symbiosis between... Show moreWith translation of the Drop-In gamma-probe, radioguidance has advanced into laparoscopic robot-assisted surgery. Global-positioning-system-like navigation can further enhance the symbiosis between nuclear medicine and surgery. Therefore, we developed a fluorescence-video-based tracking method that integrates the Drop-In with navigated robotic surgery. Methods: Fluorescent markers, integrated into the Drop-In, were automatically detected using a daVinci Firefly laparoscope. Subsequently, a declipseSPECT-navigation platform calculated the Drop-In location within the surgical field. Using a phantom (n = 3), we pursued robotic navigation on SPECT/CT, whereas intraoperative feasibility was validated during porcine surgery (n = 4). Results: Video-based tracking allowed for navigation of the Drop-In toward all lesions detected on SPECT/CT (external iliac and common iliac artery regions). Augmented-reality visualization in the surgical console indicated the distance to these lesions in real time, confirmed by the Drop-In readout. Porcine surgery underlined the feasibility of the concept. Conclusion: Optical navigation of the Drop-In probe provides a next step toward connecting nuclear medicine with robotic surgery. Show less
Manen, L. van; Birkhoff, W.A.J.; Eggermont, J.; Hoveling, R.J.M.; Nicklin, P.; Burggraaf, J.; ... ; Dijkstra, J. 2021
Background: Tissue necrosis, a consequence of inadequate tissue oxygenation, is a common post-operative complication. As current surgical assessments are often limited to visual and tactile... Show moreBackground: Tissue necrosis, a consequence of inadequate tissue oxygenation, is a common post-operative complication. As current surgical assessments are often limited to visual and tactile feedback, additional techniques that can aid in the interrogation of tissue viability are needed to improve patient outcomes. In this bi-institutional pilot study, the performance of a novel snapshot hyperspectral imaging camera to detect superficial cutaneous oxygen saturation (StO(2)) was evaluated.Methods: Healthy human volunteers were recruited at two participating centers. Cutaneous StO(2) of the forearm was determined by a snapshot hyperspectral camera on two separate study days during occlusionreperfusion of the brachial artery and after induction of local vasodilation. To calculate the blood StO(2) at each pixel in the multispectral image, spectra were selected, and fitting was performed over wavelengths ranging from 470 to 950 nm.Results: Quantitative detection of physiological changes in cutaneous StO(2) levels was feasible in all sixteen volunteers. A significant (P<0.001) decrease in cutaneous StO(2) levels from 78.3% (SD: 15.3) at baseline to 60.6% (SD: 19.8) at the end of occlusion phase was observed, although StO(2) levels returned to baseline after five minutes. Mean cutaneous StO(2) values were similar in the same subjects on separate study days (Pearson R2: 0.92 and 0.77, respectively) at both centers. Local vasodilation did not yield significant changes in cutaneous StO(2) values.Conclusions: This pilot study demonstrated the feasibility of a snapshot hyperspectral camera for detecting quantitative physiological changes in cutaneous StO(2) in normal human volunteers, and serves as a precursor for further validation in perioperative studies. Show less
Buckle, T.; Alphen, M. van; Oosterom, M.N. van; Beurden, F. van; Heimburger, N.; Wal, J.E. van der; ... ; Karakullukcu, B. 2021
Simple SummaryTranslation of tumor-specific fluorescent tracers is crucial in the realization intraoperative of tumor identification during fluorescence-guided surgery. Ex vivo assessment of... Show moreSimple SummaryTranslation of tumor-specific fluorescent tracers is crucial in the realization intraoperative of tumor identification during fluorescence-guided surgery. Ex vivo assessment of surgical specimens after topical tracer application has the potential to reveal the suitability of a potential surgical target prior to in vivo use in patients. In this study, the c-Met receptor was identified as a possible candidate for fluorescence-guided surgery in oral cavity cancer. Freshly excised tumor specimens obtained from ten patients with squamous cell carcinoma of the tongue were incubated with EMI-137 and imaged with a clinical-grade Cy5 prototype fluorescence camera. In total, 9/10 tumors were fluorescently illuminated, while non-visualization could be linked to non-superficial tumor localization. Immunohistochemistry revealed c-Met expression in all ten specimens. Tumor assessment was improved via video representation of the tumor-to-background ratio.Intraoperative tumor identification (extension/margins/metastases) via receptor-specific targeting is one of the ultimate promises of fluorescence-guided surgery. The translation of fluorescent tracers that enable tumor visualization forms a critical component in the realization of this approach. Ex vivo assessment of surgical specimens after topical tracer application could help provide an intermediate step between preclinical evaluation and first-in-human trials. Here, the suitability of the c-Met receptor as a potential surgical target in oral cavity cancer was explored via topical ex vivo application of the fluorescent tracer EMI-137. Freshly excised tumor specimens obtained from ten patients with squamous cell carcinoma of the tongue were incubated with EMI-137 and imaged with a clinical-grade Cy5 prototype fluorescence camera. In-house developed image processing software allowed video-rate assessment of the tumor-to-background ratio (TBR). Fluorescence imaging results were related to standard pathological evaluation and c-MET immunohistochemistry. After incubation with EMI-137, 9/10 tumors were fluorescently illuminated. Immunohistochemistry revealed c-Met expression in all ten specimens. Non-visualization could be linked to a more deeply situated lesion. Tumor assessment was improved via video representation of the TBR (median TBR: 2.5 (range 1.8-3.1)). Ex vivo evaluation of tumor specimens suggests that c-Met is a possible candidate for fluorescence-guided surgery in oral cavity cancer. Show less
Assessing lymph node (LN) status during tumor resection is fundamental for the staging of colorectal cancer. Current guidelines require a minimum of 12 LNs to be harvested during resection and... Show moreAssessing lymph node (LN) status during tumor resection is fundamental for the staging of colorectal cancer. Current guidelines require a minimum of 12 LNs to be harvested during resection and ultra-staging regional lymph nodes by sentinel lymph node (SLN) assessment is being extensively investigated. The current study presents novel near-infrared (NIR) fluorescent dyes for simultaneous pan lymph node (PanLN; regional) and SLN mapping. PanLN-Forte was intravenously injected in mice and assessed for accumulation in regional LNs. SLN800 was injected intradermally in mice, after which the collection and retention of fluorescence in SLNs were measured using indocyanine green (ICG) and its precursor, SLN700, as references. LNs in the cervical, inguinal, jejunal, iliac, and thoracic basins could clearly be distinguished after a low dose intravenous injection of PanLN-Forte. Background fluorescence was significantly lower compared to the parent compound ZW800-3A (p < 0.001). SLN700 and SLN800 specifically targeted SLNs with fluorescence being retained over 40-fold longer than the current clinically used agent ICG. Using SLN700 and SLN800, absolute fluorescence in SLN was at least 10 times higher than ICG in second-tier nodes, even at 1 hour post-injection. Histologically, the fluorescent signal localized in the LN medulla (PanLN-Forte) or sinus entry (SLN700/SLN800). PanLN-Forte and SLN800 appear to be optimal for real-time NIR fluorescence imaging of regional and SLNs, respectively. Show less
Beurden, F. van; Willigen, D.M. van; Vojnovic, B.; Oosterom, M.N. van; Brouwer, O.R.; Poel, H.G. van der; ... ; Buckle, T. 2020
With the rise of fluorescence-guided surgery, it has become evident that different types of fluorescence signals can provide value in the surgical setting. Hereby a different range of targets have... Show moreWith the rise of fluorescence-guided surgery, it has become evident that different types of fluorescence signals can provide value in the surgical setting. Hereby a different range of targets have been pursued in a great variety of surgical indications. One of the future challenges lies in combining complementary fluorescent readouts during one and the same surgical procedure, so-called multi-wavelength fluorescence guidance. In this review we summarize the current clinical state-of-the-art in multi-wavelength fluorescence guidance, basic technical concepts, possible future extensions of existing clinical indications and impact that the technology can bring to clinical care. Show less
Rietbergen, D.D.D.; Meershoek, P.; Kleinjan, G.H.; Donswijk, M.; Olmos, R.A.V.; Leeuwen, F.W.B. van; ... ; Hage, J.A. van der 2020
Objective The hybrid tracer indocyanine green (ICG)-Tc-99m-nanocolloid has been introduced for sentinel node imaging. However, until now, a comparison of this tracer with other radiocolloids with a... Show moreObjective The hybrid tracer indocyanine green (ICG)-Tc-99m-nanocolloid has been introduced for sentinel node imaging. However, until now, a comparison of this tracer with other radiocolloids with a larger particle size has not been effectuated. Based on a head-to-head evaluation in patients with melanoma, we have compared ICG-Tc-99m-nanocolloid (particle size 5-80 nm) with(99m)Tc-Senti-Scint (particle size 100-600 nm) to establish differences in drainage pattern and sentinel node localization using lymphoscintigraphy and single-photon emission computed tomography combined with computer tomography (SPECT-CT) in melanoma patients scheduled for sentinel node biopsy. Methods Twenty-five patients (mean age: 56.9 years, range: 25-79 years) with a melanoma scheduled for SLN biopsy prior to (re)excision of the primary lesion (scar) were prospectively included following a two-day procedure. The first day, after(99m)Tc-Senti-Scint injection in four intradermal depots around the primary lesion or scar, early/delayed lymphoscintigraphy and SPECT-CT images were acquired. The injection sites were marked. The second day, after assessing lymph node radioactivity using planar scintigraphy, ICG-Tc-99m-nanocolloid was injected at the previously marked skin points and imaging was performed. The paired planar and SPECT-CT images of both tracers were evaluated with respect to drainage patterns, SLN visualization and non-SLN appearing. Results Twenty-four out of 25 patients were evaluable. SLN visualization on a patient basis was 100% for ICG-Tc-99m-nanocolloid and 96% for(99m)Tc-Senti-Scint, whereas uptake in non-SLNs was found in, respectively, 71% (17/24) and 61% (14/23). Concordance in drainage to 45 lymph node basins was 91%. Discordant drainage was found for two melanomas in the head-and-neck and one in the clavicular area. Unique lymph node basins were seen in 44/45 (98%) for ICG-Tc-99m-nanocolloid and 42/45 (93%) for(99m)Tc-Senti-Scint. Concerning identified SLNs, the number was similar for both tracers (n = 58); however, more non-SLNs (65 vs 50) were visualized with ICG-Tc-99m-nanocolloid than with(99m)Tc-Senti-Scint. Conclusion A slightly higher SLN visualization accompanied by a tendency to depict more non-SLNs was found for ICG-Tc-99m-nanocolloid. Excepting the head and neck area, an overall high concordance in drainage was found for both radiotracers. With an additional value for the hybrid tracer due to the combination of preoperative imaging and the additional visual signal in the operation room, added by the fluorescent component of the hybrid tracer, there was a preference for ICG-Tc-99m-nanocolloid. Show less
Muijnck, C. de; Gorkom, Y. van; Duijvenvoorde, M. van; Eghtesadi, M.; Dekker-Ensink, G.; Bhairosingh, S.S.; ... ; Sier, C.F.M. 2020
Background: Targeted image-guided surgery is based on the detection of tumor cells after administration of a radio-active or fluorescent tracer. Hence, enhanced binding of a tracer to tumor tissue... Show moreBackground: Targeted image-guided surgery is based on the detection of tumor cells after administration of a radio-active or fluorescent tracer. Hence, enhanced binding of a tracer to tumor tissue compared to healthy tissue is crucial. Various tumor antigens have been evaluated as possible targets for image-guided surgery of breast cancer, with mixed results. Methods: In this study we have evaluated tyrosine kinase receptor EphB4, a member from the Eph tyrosine kinase receptor family, as a possible target for image-guided surgery of breast cancers. Two independent tissue micro arrays, consisting of matched sets of tumor and normal breast tissue, were stained for EphB4 by immunohistochemistry. The intensity of staining and the percentage of stained cells were scored by two independent investigators. Results: Immunohistochemical staining for EphB4 shows that breast cancer cells display enhanced membranous expression compared to adjacent normal breast tissue. The enhanced tumor staining is not associated with clinical variables like age of the patient or stage or subtype of the tumor, including Her2-status. Conclusion: These data suggest that EphB4 is a promising candidate for targeted image-guided surgery of breast cancer, especially for Her2 negative cases. Show less
Baart, V.M.; Duijn, C. van; Egmond, S.L. van; Dijckmeester, W.A.; Jansen, J.C.; Vahrmeijer, A.L.; ... ; Cohen, D. 2020
R0 resection is paramount in cutaneous squamous cell carcinoma (CSCC) and head and neck squamous cell carcinoma (HNSCC). However, in the setting of recurrence, immunocompromised patients, or non... Show moreR0 resection is paramount in cutaneous squamous cell carcinoma (CSCC) and head and neck squamous cell carcinoma (HNSCC). However, in the setting of recurrence, immunocompromised patients, or non-keratinizing squamous cell carcinoma (SCC) with a spindle growth pattern, tumor borders are difficult, if not impossible, to determine. Fluorescence-guided surgery (FGS) aids in this differentiation. Potential targets for FGS of CSCC and HNSCC were evaluated. Most sections stained intensely for alpha v beta 6 and epidermal growth factor receptor (EGFR) on tumor cells. Normal epithelium stained less for alpha v beta 6 than for EGFR. In addition, soft tissue and stroma stained negative for both, allowing for clear discrimination of the soft tissue margin. Tumor cells weakly expressed urokinase plasminogen activator receptor (uPAR) while expression on stromal cells was moderate. Normal epithelium rarely expressed uPAR, resulting in clear discrimination of superficial margins. Tumors did not consistently express integrin beta 3, carcinoembryonic antigen, epithelial cell adhesion molecule, or vascular endothelial growth factor A. In conclusion, alpha v beta 6 and EGFR allowed for precise discrimination of SSC at the surgically problematic soft tissue margins. Superficial margins are ideally distinguished with uPAR. In the future, FGS in the surgically challenging setting of cutaneous and mucosal SCC could benefit from a tailor-made approach, with EGFR and alpha v beta 6 as targets. Show less
Meershoek, P.; Buckle, T.; Oosterom, M.N. van; Kleinjan, G.H.; Poel, H.G. van der; Leeuwen, F.W.B. van 2020
Tracers can help visualize the lymphatic drainage patterns and sentinel nodes (SNs) of individual prostate cancer patients. To determine the role of nuclear medicine in surgical guidance, in... Show moreTracers can help visualize the lymphatic drainage patterns and sentinel nodes (SNs) of individual prostate cancer patients. To determine the role of nuclear medicine in surgical guidance, in particular the positional guidance of a SPECT/CT-based 3-dimensional imaging road map, in this process we studied to what extent fluorescence guidance underestimated the number of target lesions relative to radioguidance. Methods: SPECT/CT imaging was performed after intraprostatic tracer administration of either indocyanine green (ICG)-Tc-99m-nanocolloid (hybrid-tracer group) or Tc-99m-nanocolloid to create a road map that depicted all SNs. Patients who received Tc-99m-nanocolloid were injected with "free" ICG immediately before surgery. Before unmasking, fluorescence guidance was used for intraoperative SN identification. This was followed by extended pelvic lymph node dissection (ePLND). After unmasking of the SPECT/CT images, the number of missed SNs was recorded and their resection was pursued when there was no risk of intraoperative complications. Results: Preoperative SPECT/CT revealed no differences in the SN identification rate between ICG-Tc-99m-nanocolloid and Tc-99m-nanocolloid. However, fluorescence guidance allowed intraoperative removal of all SNs in only 40% of patients in the hybrid-tracer group and 20% of patients in the free-ICG group. Overall, 75.9% of the intraoperatively resected SNs in the hybrid-tracer group and 51.8% of the SNs in the free-ICG group were removed solely under fluorescence guidance. During ePLND, 22 additional SNs were resected (7 in the hybrid-tracer group and 15 in the free-ICG group). After unmasking, 18 remaining SNs were identified (6 in the hybrid group and 12 in the free-ICG group). In the free-ICG group, ex vivo evaluation of the excised specimens revealed that 14 SNs removed under ePLND or after unmasking contained radioactivity but no fluorescence. Conclusion: The preoperative imaging road map provided by SPECT/CT enhanced the detection of prostate SNs in more ectopic locations in 17 of the 25 patients, and the hybrid tracer ICG-Tc-99m-nanocolloid was shown to outperform free ICG. Overall, fluorescence-guided pelvic nodal surgery underestimated the number of SNs in 60%-80% of patients. Show less
Hinsenveld, F.J.; Wit, E.M.K.; Leeuwen, P.J. van; Brouwer, O.R.; Donswijk, M.L.; Tillier, C.N.; ... ; Poel, H.G. van der 2020
Our objective was to determine the diagnostic capabilities of combined prostate-specific membrane antigen (PSMA) PET/CT and sentinel node (SN) biopsy in PSMA PET/CT-negative patients for primary... Show moreOur objective was to determine the diagnostic capabilities of combined prostate-specific membrane antigen (PSMA) PET/CT and sentinel node (SN) biopsy in PSMA PET/CT-negative patients for primary lymph node (LN) staging in prostate cancer (PCa) patients. Methods: Between January 2017 and March 2019, retrospectively, all consecutive patients with diagnosed intermediate- or high-risk primary PCa who underwent preoperative PSMA PET/CT (Ga-68 or F-18-DCFPyL) followed by robot-assisted radical prostatectomy and extended pelvic LN dissection (ePLND) were included. All patients without suspected LN metastases on PSMA PET/CT were considered candidates for SN biopsy with indocyanine green-Tc-99m-nanocolloid or Tc-99m-nanocolloid with free indocyanine green used as tracers. The ePLND was used as a reference standard. Results: Of 53 patients, 22 had positive PSMA PET/CT results and 31 underwent subsequent SN biopsy after negative PSMA PET/CT results. In total, 23 patients (43%) were pN1, of whom 6 (26%) had negative PSMA PET/CT results and underwent subsequent SN biopsy. The combined use of SN biopsy and PSMA PET/CT identified all pN1 patients (100% sensitivity; 95% confidence interval, 86%-100%) and performed correct nodal staging in 50 of 53 patients (94% diagnostic accuracy; 95% confidence interval, 84%-99%). SN biopsy identified significantly smaller LN metastases (median diameter, 2.0 mm; interquartile range, 1.0-3.8 mm) than PSMA PET/CT (median diameter, 5.5 mm; interquartile range, 2.6-9.3 mm; P = 0.007). Conclusion: Combining both modalities led to a 94% accuracy for nodal staging in diagnosed intermediate- and high-risk primary PCa. Adding SN biopsy in patients with negative PSMA PET/CT results increased the combined sensitivity to 100% for detecting nodal metastases at ePLND. This diagnostic accuracy may provide valuable information for directing further treatment in PCa patients, such as the use of PSMA PET/CT and SN biopsy rather than ePLND as the preferred approach for staging before radiotherapy. Show less
Hensbergen, A.W.; Buckle, T.; Willigen, D.M. van; Schottelius, M.; Welling, M.M.; Wijk, F.A. van der; ... ; Leeuwen, F.W.B. van 2020
Prostate cancer surgery is currently being revolutionized by the use of prostate-specific membrane antigen (PSMA)-targeted radiotracers, for example, (99)mTc-labeled PSMA tracer analogs for... Show moreProstate cancer surgery is currently being revolutionized by the use of prostate-specific membrane antigen (PSMA)-targeted radiotracers, for example, (99)mTc-labeled PSMA tracer analogs for radioguided surgery. The purpose of this study was to develop a second-generation (99)mTc-labeled PSMA-targeted tracer incorporating a fluorescent dye. Methods: Several PSMA-targeted hybrid tracers were synthesized: glutamic acid- urea-lysine (EuK)-Cy5-mas(3), EuK-(SO3)Cy5-mas(3), EuK-Cy5(SO3)-mas(3), EuK-(Ar)Cy5-mas(3), and EuK-Cy5(Ar)-mas(3); the Cy5 dye acts as a functional backbone between the EuK targeting vector and the 2-mercaptoacetyl-seryl-seryl-seryl (mas(3)) chelate to study the dye's interaction with PSMA's amphipathic entrance funnel. The compounds were evaluated for their photophysical and chemical properties and PSMA affinity. After radiolabeling with (99)mTc, we performed in vivo SPECT imaging, biodistribution, and fluorescence imaging on BALB/c nude mice with orthotopically transplanted PC346C tumors. Results: The dye composition influenced the photophysical properties (brightness range 0.3-1.5 x 10(4) M-1 x cm(-1)), plasma protein interactions (range 85.0% +/- 2.3%-90.7%+/- 1.3% bound to serum, range 76%+/- 0%-89%+/- 6% stability in serum), PSMA affinity (half-maximal inhibitory concentration [IC50] range 19.2 +/- 5.8-175.3 +/- 61.1 nM) and in vivo characteristics (tumorto-prostate and tumor-to-muscle ratios range 0.02 +/- 0.00-154.73 +/- 28.48 and 0.46 +/- 0.28-5,157.50 +/- 949.17, respectively; renal, splenic, and salivary retention). Even though all tracer analogs allowed tumor identification with SPECT and fluorescence imaging, (99)mTc-EuK(SO3)Cy5-mas(3) had the most promising properties (e.g., half-maximal inhibitory concentration, 19.2 +/- 5.8, tumor-to-muscle ratio, 5,157.50 +/- 949.17). Conclusion: Our findings demonstrate the intrinsic integration of a fluorophore in the pharmacophore in PSMA-targeted smallmolecule tracers. In this design, having 1 sulfonate on the indole moiety adjacent to EuK ((99)mTc-EuK-(SO3)Cy5-mas(3)) yielded the most promising tracer candidate for imaging of PSMA. Show less
Leeuwen, F.W.B. van; Schottelius, M.; Brouwer, O.R.; Vidal-Sicart, S.; Achilefu, S.; Klode, J.; ... ; Buckle, T. 2020
Since its introduction to the diagnostic pathway for prostate cancer management, prostate-specific membrane antigen (PSMA)-ligand PET has demonstrated great potential. PSMA-ligand imaging is... Show moreSince its introduction to the diagnostic pathway for prostate cancer management, prostate-specific membrane antigen (PSMA)-ligand PET has demonstrated great potential. PSMA-ligand imaging is increasingly influencing therapeutic decision making, although its impact on patient outcomes still needs to be defined. One relatively new application, enabled through chemical and engineering efforts, is PSMA-guided surgery. This review highlights the potential of PSMA-guided surgery and discusses its implications in lymph node dissection in primary and recurrent prostate cancer. Show less
Buckle, T.; Wal, S. van der; Willigen, D.M. van; Aalderink, G.; KleinJan, G.H.; Leeuwen, F.W.B. van 2020
Introduction: Adequate signal to background ratios are critical for the implementation of fluorescence-guided surgery technologies. While local tracer administrations help to reduce the chance of... Show moreIntroduction: Adequate signal to background ratios are critical for the implementation of fluorescence-guided surgery technologies. While local tracer administrations help to reduce the chance of systemic side effects, reduced spatial migration and non-specific tracer diffusion can impair the discrimination between the tissue of interest and the background. To combat background signals associated with local tracer administration, we explored a pretargeting concept aimed at quenching non-specific fluorescence signals. The efficacy of this concept was evaluated in an in vivo neuronal tracing set-up.Methods: Neuronal tracing was achieved using a wheat germ agglutinin (WGA) lectin. functionalized with an azide-containing Cy5 dye (N-3-Cy5-WGA). A Cy7 quencher dye (Cy7-DBCO) was subsequently used to yield Cy7-Cy5-WGA, a compound wherein the Cy5 emission is quenched by Forster resonance energy transfer to Cy7. The photophysical properties of N-3-Cy5-WGA and Cy7-Cy5-WGA were evaluated together with deactivation kinetics in situ, in vitro (Schwannoma cell culture), ex vivo (muscle tissue from mice; used for dose optimization), and in vivo (nervus ischiadicus in THY-1 YFP mice).Results: In situ, conjugation of Cy7-DBCO to N-3-Cy5-WGA resulted in >90% reduction of the Cy5 fluorescence signal intensity at 30 minutes after addition of the quencher. In cells, pretargeting with the N-3-Cy5-WGA lectin yielded membranous staining, which could efficiently be deactivated by Cy7-DBCO over the course of 30 minutes (91% Cy5 signal decrease). In ex vivo muscle tissue, administration of Cy7-DBCO at the site where N-3-Cy5-WGA was injected induced 80-90% quenching of the Cy5-related signal after 10-20 minutes, while the Cy7-related signal remained stable over time. In vivo, Cy7-DBCO effectively quenched the non-specific background signal up to 73% within 5 minutes, resulting in a 50% increase in the signal-to-background ratio between the nerve and injection site.Conclusion: The presented pretargeted fluorescence-quenching technology allowed fast and effective reduction of the background signal at the injection site, while preserving in vivo nerve visualization. While this proof-of-principle study was focused on imaging of nerves using a fluorescent WGA-lectin, the same concept could in the future also apply to applications such as sentinel node imaging. Show less
