Fluorescence-Guided Surgery

A Near-Infrared Fluorescent Macromolecular Dye for Precise Identification of Glioblastoma Boundaries

Glioblastoma (GBM) is a highly invasive tumor with poorly defined boundaries, often leaving residual tissue after surgery, which contributes to the recurrence and poor prognosis. A critical challenge in GBM treatment is the precise identification of tumor boundaries during surgery to achieve a safe and complete resection. In this study, we present a novel near-infrared fluorescent agent, IR-PEG-cRGD, that is designed to accurately delineate GBM boundaries for surgical navigation of tumor resection. IR-PEG-cRGD is successfully prepared from the cyanine dye IR-820, which is conjugated to poly(ethylene glycol) (PEG) to prolong circulation time and enhance tumor accumulation. Additionally, a glioma-targeting peptide (cRGD, cyclo(Arg-Gly-Asp-d-Phe-Cys)) is conjugated to PEG to selectively target GBM. IR-PEG-cRGD demonstrates effective targeting and enrichment in subcutaneous human-derived GBM mice models, enabling specific distinguishing of the GBM margin from the surrounding parenchyma with a high signal-to-background ratio (SBR) of 4.79. Moreover, IR-PEG-cRGD can pass across the blood-brain barrier (BBB) efficiently. These findings indicate that IR-PEG-cRGD can serve as a valuable tool for the precise intraoperative delineation of GBM boundaries, aiding in safe and complete tumor resection.

The Medical Basis for the Photoluminescence of Indocyanine Green

Indocyanine green (ICG), a near-infrared (NIR) fluorescent dye with unique photoluminescent properties, is a helpful tool in many medical applications. ICG produces fluorescence when excited by NIR light, enabling accurate tissue visualization and real-time imaging. This study investigates the fundamental processes behind ICG's photoluminescence as well as its present and possible applications in treatments and medical diagnostics. Fluorescence-guided surgery (FGS) has been transformed by ICG's capacity to visualize tumors, highlight blood flow, and facilitate lymphatic mapping, all of which have improved surgical accuracy and patient outcomes. Furthermore, the fluorescence of the dye is being studied for new therapeutic approaches, like photothermal therapy, in which NIR light can activate ICG to target and destroy cancer cells. We go over the benefits and drawbacks of ICG's photoluminescent qualities in therapeutic contexts, as well as current studies that focus on improving its effectiveness, security, and adaptability. More precise disease detection, real-time monitoring, and tailored therapy options across a variety of medical specialties are made possible by the ongoing advancement of ICG-based imaging methods and therapies. In the main part of our work, we strive to take into account the latest reports; therefore, we used clinical articles going back to 2020. However, for the sake of the theoretical part, the oldest article used by us is from 1995.

Novel Intraoperative Applications of Fluorescence Imaging Using Indocyanine Green in Pediatric Urology

PURPOSE OF REVIEW

Near-infrared fluorescence imaging (NIRF) with the use of indocyanine green (ICG) has been recently adopted in pediatric urology after its well-published use in the adult population. As a powerful tool that can help delineate complex anatomy and congenital anomalies, we discuss the various applications of this imaging in minimally invasive and open surgery in pediatric urology.

RECENT FINDINGS

The most reported applications of ICG in pediatric urology are within minimally invasive surgery, particularly varicoceles, renal surgery such as nephrectomies and renal tumor excision, mimicking its use in adult urology. ICG has also been applied to reconstructive urology such as ureteral reconstruction, hypospadias repair and bladder exstrophy. Despite its safety and more widespread use in pediatric surgery, all published studies in pediatric urology to date have been limited to small and single-center experiences, reflecting the novel nature of this technology in this field. ICG has been shown to be safe and effective in children, particularly in those with complex anatomy and in technically challenging surgeries. Future studies should focus on standardized protocols for children and multi-center comparative studies.

Full-Spectrum Photography in Cadaveric Surgical Neuroanatomy: Anatomical Nuances Beyond the Naked Eye

BACKGROUND

Anatomical dissection is a fundamental part of surgical education, but it can be challenging to visualize the subtle details of anatomy. Full-spectrum photography (FSP) is a technique that uses cameras that can capture light in a wider range of wavelengths compared to traditional cameras. This technical laboratory note introduces a method using noncontrast-dependent FSP to improve the visualization of neuroanatomical structures during cadaveric dissection for surgical neuroanatomy.

METHODS

The techniques described below were employed to routinely capture anatomical images in the Skull Base and Cerebrovascular Laboratory at the University of California, San Francisco from February 2022 to August 2024, when capturing anatomical exposures of 20 specimens. We used 3 different full-spectrum modalities: 720-nm infrared, ultraviolet (UV) reflectance, and UV fluorescence and a modified mirror-less camera without hot mirror.

RESULTS

The application of FSP yielded high-clarity images across various imaging modalities, each enhancing specific anatomical structures. Infrared 720-nm images showed the general smooth texture of the surface structure of the cadaver, UV reflectance, and fluorescence provided an enhancement of calcified structures, nerve fibers, microvascular components, and melanin. Combining these techniques with other imaging modalities, such as visible imaging and photogrammetry, proved to be both straightforward and feasible.

CONCLUSIONS

FSP offers a valuable enhancement to anatomical dissections and education. It provides a noninvasive means to characterize anatomical structures with greater clarity, highlighting features that may be challenging to observe with the naked eye or standard visible-light photography.

Use of Ambient Light Compatible Fluorescence-Guided Surgical Technology for Objective Assessment of Flap Perfusion in Autologous Breast Reconstruction

BACKGROUND

 Decreased autologous flap vascular perfusion can lead to secondary procedures. Fluorescence angiography during surgery reduces the probability of repeat surgery but suffers from interpretation variability. Recently, the OnLume Avata System was developed, which evaluates real-time vascular perfusion in ambient light. This study aims to predict complications in autologous breast reconstruction using measures of relative intensity (RI) and relative area (RA).

METHODS

 Patients undergoing autologous breast reconstruction underwent intraoperative tissue perfusion assessment using the OnLume Avata System. Post-hoc image annotation was completed by labeling areas of the flap interpreted to be "Well Perfused," "Questionably Perfused," and "Under Perfused." RIs and RAs were calculated for the marked areas. Primary complications of interest were overall complication rate, fat and mastectomy skin flap necrosis, and surgical revision. Logistic regression was applied to determine the odds of developing a complication based on RI and RA for each image.

RESULTS

 A total of 25 patients (45 flaps) were included. In total, 17 patients (68%) developed at least one complication. Patients who developed any complication (p = 0.02) or underwent a surgical revision for complications (p = 0.02) had statistically lower RI of under-perfused portions of the flap. Patients with greater areas of under-perfused flap had a significantly higher risk of developing fat necrosis (odds ratio [OR]: 5.71, p = 0.03) and required a revision operation (OR: 1.10, p = 0.01).

CONCLUSION

 Image-based interpretation using the OnLume Avata System correlated with the risk of developing postoperative complications that standard fluorescence imaging systems may not appreciate. This information can benefit surgeons to improve perfusion assessment and intraoperative decision-making.

A Pair of Fluorescent Probes Enabling Precise Diagnosis of Liver Cancer by Complementary Imaging

Hepatocellular carcinoma (HCC) is by far the predominant malignant liver cancer, with both high morbidity and mortality. Early diagnosis and surgical resections are imperative for improving the survival of HCC patients. However, limited by clinical diagnosis methods, it is difficult to accurately distinguish tumor tissue and its boundaries in the early stages of cancer. Herein, we report two fluorescent probes, cLG and hLR, for the detection of cancer and healthy cells, respectively, enabling the precise diagnosis of liver cancer by providing complementary imaging. These two fluorescent probes could selectively stain the target cells in the liver tissue imaging, which is confirmed by H&E and antibody staining. Moreover, for the first time, the cancerous area and healthy area are clearly identified by the cocktail of these two probes, suggesting its potential to be used in fluorescence-guided surgery. Finally, we identify transporter SLC27A2 as the gating target of cLG through a systematic transporter screen using a CRISPR activation library. SMPD1 was identified as the target of hLR through a thermal proteome profiling. Therefore, the development of these two highly specific probes offers complementary imaging and provides a unique diagnostic tool for cancer disease, even for fluorescence-guided surgery.

Pursuing theranostics: a multimodal architecture approach

Theranostics is a field of nuclear medicine which uses the same targeting vector and chelating system for both a diagnostic and therapeutic radionuclide, allowing for uniformity in imaging and treatment. This growing field requires the development of more flexible chelate systems that permit novel targeting strategies. Toward this end, a multimodal architecture has been realized, making use of a phosphazene-based core and click chemistry to achieve a flexible and customizable scaffold. The six arm phosphazene-based core can scaffold six DTPA chelating motifs or a mixed set of 3 : 3 DTPA : DFO chelates resulting in two multimodal compounds, pDbDt and pDbDtDf, respectively. Terbium complexes displayed strong luminescence, supporting that the structures act as an organic antenna for luminescence. Metal displacement titration studies confirmed the desired structures as well as the capability for heterometallic labeling of the structures. These structures were found to have high thermal and biological stability in vitro. Radiolabeling of each compound resulted in high molar activity labeling of each compound: 169 MBq nmol-1: [161Tb]Tb-pDbDt, 170 MBq nmol-1: [89Zr]Zr-pDbDtDf, and the mixed radiolabeling illustrated chelation of both radionuclides in a 1 : 1 ratio. This multimodal architecture is promising as a heterometallic structure for coupling of both a diagnostic and a therapeutic radionuclide with a highly customizable core structure.

Computational Chemistry Study of pH-Responsive Fluorescent Probes and Development of Supporting Software

This study employs quantum chemical computational methods to predict the spectroscopic properties of fluorescent probes 2,6-bis(2-benzimidazolyl)pyridine (BBP) and (E)-3-(2-(1H-benzo[d]imidazol-2-yl)vinyl)-9-(2-(2-methoxyethoxy)ethyl)-9H-carbazole (BIMC). Using time-dependent density functional theory (TDDFT), we successfully predicted the fluorescence emission wavelengths of BBP under various protonation states, achieving an average deviation of 6.0% from experimental excitation energies. Molecular dynamics simulations elucidated the microscopic mechanism underlying BBP's fluorescence quenching under acidic conditions. The spectroscopic predictions for BIMC were performed using the STEOM-DLPNO-CCSD method, yielding an average deviation of merely 0.57% from experimental values. Based on Einstein's spontaneous emission formula and empirical internal conversion rate formulas, we calculated fluorescence quantum yields for spectral intensity calibration, enabling the accurate prediction of experimental spectra. To streamline the computational workflow, we developed and open-sourced the EasySpecCalc software v0.0.1 on GitHub, aiming to facilitate the design and development of fluorescent probes.

Detection properties of indium-111 and IRDye800CW for intraoperative molecular imaging use across tissue phantom models

Significance

Intraoperative molecular imaging (IMI) enables the detection and visualization of cancer tissue using targeted radioactive or fluorescent tracers. While IMI research has rapidly expanded, including the recent Food and Drug Administration approval of a targeted fluorophore, the limits of detection have not been well-defined.

Aim

The ability of widely available handheld intraoperative tools (Neoprobe and SPY-PHI) to measure gamma decay and fluorescence intensity from IMI tracers was assessed while varying characteristics of both the signal source and the intervening tissue or gelatin phantoms.

Approach

Gamma decay signal and fluorescence from tracer-bearing tumors (TBTs) and modifiable tumor-like inclusions (TLIs) were measured through increasing thicknesses of porcine tissue and gelatin in custom 3D-printed molds. TBTs buried beneath porcine tissue were used to simulate IMI-guided tumor resection.

Results

Gamma decay from TBTs and TLIs was detected through significantly thicker tissue and gelatin than fluorescence, with at least 5% of the maximum signal observed through up to 5 and 0.5 cm, respectively, depending on the overlying tissue type or gelatin.

Conclusions

We developed novel systems that can be fine-tuned to simulate variable tumor characteristics and tissue environments. These were used to evaluate the detection of fluorescent and gamma signals from IMI tracers and simulate IMI surgery.

Indocyanine Blue (ICB) as a Functional Alternative to Indocyanine Green (ICG) for Enhanced 700 nm NIR Imaging

Despite significant advancements in bioimaging technology, only a limited number of fluorophores are currently approved for clinical applications. Indocyanine green (ICG) is the first FDA-approved near-infrared (NIR) fluorophore and has significantly advanced clinical interventions over the past three decades. However, its single-channel imaging at 800 nm emission is often insufficient for capturing comprehensive diagnostic information during surgery. In this study, we evaluate indocyanine blue (ICB), an ICG analog with a shorter polymethine bridge, as a promising candidate for multi-channel NIR imaging. ICB demonstrated peak absorption and emission approximately 100 nm shorter than ICG in aqueous solutions, placing it within the 700 nm range of the NIR window. Furthermore, ICB exhibited favorable solubility and optical properties in aqueous environments, supporting its potential for in vivo imaging applications. Notably, ICB shows rapid systemic clearance, likely due to its lower molecular weight, which facilitates clear visualization in angiography, cholangiography, and lymph node mapping with minimal background interference. Additionally, dual-channel imaging of tumors and lymph nodes was achieved using a tumor-targeting fluorophore in conjunction with ICB, illustrating the potential for enhanced intraoperative guidance. ICB emitting at 700 nm, therefore, can be useful in NIR imaging, broadening the possibilities for improved diagnostic accuracy and therapeutic outcomes in clinical settings.

Insights into Cancer Cell Imaging Probes Based on Chalcone Scaffolds: Theoretical and Experimental Perspectives

The research article details the synthesis of chalcone-chromone-based scaffolds via multicomponent reactions. These compounds were characterized using conventional spectroscopic methods, including NMR (1H and 13C), FT-IR, and HR-MS. Among the synthesized scaffolds, AZBNPy stood out, exhibiting exceptional DNA and protein targeting capabilities with superior binding parameters. Molecular docking studies indicated that AZBNPy has potential as a potent anticancer agent and a probe for cancer cell imaging. The findings showed that AZBNPy effectively inhibited cell proliferation and induced cell death by targeting HER-2, PARP-2, and HFR in MCF-7 cells. Additionally, in vitro fluorescence imaging studies confirmed AZBNPy's specificity for cancer cell receptors, displaying strong fluorescence in human breast cancer tissues. The clinical application of AZBNPy as an optical imaging agent holds significant promise in aiding surgeons with the precise identification and removal of cancerous tissues, potentially improving patient outcomes and survival rates.

pH-Activatable Molecular Probe for COX-2 Imaging in Human Oral Squamous Carcinoma Cells and Patient-Derived Tissues

For developing a successful cancer therapeutic modality, the early precise detection of cancer cells in patient biopsies in oral squamous cell carcinoma (OSCC) is crucial. This could help researchers create new diagnostic and therapeutic tools and assist clinicians in recommending more effective treatment plans and improving patient survival. We have developed an SMPD, cyclooxygenase-2 (COX-2) targeting pH-activable fluorophore named CNP, combining a potent COX-2 inhibitor, celecoxib, linked to a naphthalimide fluorophore with an acidic microenvironment-responsive piperazine moiety for specific optical imaging of OSCC in cells and patient tissues. Compared to reference probe RNP lacking celecoxib, CNP selectively enters the COX-2 overexpressing oral cancer cells. Its acidity-responsive imaging response enhances selectivity over cancers with lower COX-2 expression levels and normal cells. Further, CNP is demonstrated in imaging OSCC cells in patient-derived biopsies. Thus, multifunctional CNP shows potential in exploring more reagents for fluorescence-based detection of OSCC cells in patient tissues with translational applications.

Indocyanine green and near-infrared fluorescence-guided surgery for gastric cancer: a narrative review

In recent years, indocyanine green (ICG) and near-infrared (NIR) fluorescence-guided surgery has become a versatile and well-researched tool for gastric cancer treatment. Our narrative review aims to explore the applications, benefits, and challenges that are associated with this technique. Initially used to detect sentinel lymph nodes in early gastric cancer, its scope has broadened to include several clinical applications. Its most notable advantages are the ability to guide standard lymphadenectomy, intraoperatively localize tumors and define tumor margins. Despite these advantages, there are still ongoing discussions regarding its accuracy, lack of standardized administration, and oncologic safety in sentinel node navigation surgery. The limited tumor specificity of ICG has been especially put into question, hindering its ability to accurately differentiate between malignant and healthy tissue. With ongoing innovations and its integration into newer endoscopic and robotic systems, ICG-NIR fluorescence imaging shows promise in becoming a standard tool in the surgical treatment of gastric cancer.

Potential Probes for Targeted Intraoperative Fluorescence Imaging in Gastric Cancer

Gastric cancer (GC) is a malignant tumor of the gastrointestinal tract associated with high mortality rates and accounting for approximately 1 million new cases diagnosed annually. Surgery, particularly radical gastrectomy, remains the primary treatment; however, there are currently no specific approaches to better distinguish malignant from healthy tissue or to differentiate between metastatic and non-metastatic lymph nodes. As a result, surgeons have to remove all lymph nodes indiscriminately, increasing intraoperative risks for patients and prolonging hospital stay. Near-infrared fluorescence imaging with indocyanine green (ICG) can provide real-time visualization of the surgical field using both conventional laparoscopy and robotic mini-invasive precision surgery platforms. However, its application shows some limits, as ICG is a non-targeted contrast agent. Several studies are now investigating the potential efficacy of fluorescent targeted agents that could selectively bind to the tumor tissue, offering a valuable tool for metastatic mapping during robotic gastrectomy. This review aims to summarize the key fluorescent agents that have been developed to recognize GC markers, as well as those targeting the tumor microenvironment (TME) and metabolic features. These agents hold great potential as valuable tools for enhancing precision surgery in robotic gastrectomy procedures improving the clinical recovery of GC patients.

Nano-fluorescence imaging: advancing lymphatic disease diagnosis and monitoring

The lymphatic system plays a crucial role in maintaining physiological homeostasis and regulating immune responses. Traditional imaging modalities such as magnetic resonance imaging, computerized tomography, and positron emission tomography have been widely used to diagnose disorders in the lymphatic system, including lymphedema, lymphangioma, lymphatic metastasis, and Castleman disease. Nano-fluorescence technology has distinct advantages-including naked-eye visibility, operational simplicity, portability of the laser, and real-time visibility-and serves as an innovative alternative to traditional imaging techniques. This review explores recent advancements in nano-fluorescence imaging aimed at enhancing the resolution of lymphatic structure, function, and immunity. After delineating the fundamental characteristics of lymphatic systems, it elaborates on the development of various nano-fluorescence systems (including nanoparticles incorporating fluorescent dyes and those with intrinsic fluorescence) while addressing key challenges such as photobleaching, limited tissue penetration, biocompatibility, and signal interference from biomolecules. Furthermore, this review highlights the clinical applications of nano-fluorescence and its potential integration into standard diagnostic protocols. Ongoing advancements in nanoparticle technology underscore the potential of nano-fluorescence to revolutionize the diagnosis and treatment of lymphatic disease.

Safety and efficacy of "hydro-fluorescein" technique in removing Tenon in pterygium surgery: a 1-year follow-up study

PURPOSE

To assess the effectiveness and safety of the "hydro-fluorescein" adjunct technique for primary pterygium removal.

DESIGN/METHODS

A non-randomized prospective study was conducted for various types of pterygium excision with superior bulbar conjunctival autograft (CAG) and fibrin glue. We introduced fluorescein staining to ensure thorough elimination of the Tenon tissue around the bare sclera area and the CAG. The primary outcome was the recurrence rate, and the secondary outcome was any complication associated with fluorescein staining.

RESULTS

Ninety-three participants with primary pterygium of Grades 1-3 were recruited and all completed follow-up for at least 1 year. No recurrence was identified during the follow-up period and no long-term adverse reactions were reported with the "hydro-fluorescein" method.

CONCLUSION

"Hydro-fluorescein" is effective and a safe adjunct in primary pterygium removal and is effective in various grades of pterygia to minimize recurrence with no adverse reaction within 1 year.

Intra-Operative Tumour Detection and Staging in Pancreatic Cancer Surgery: An Integrative Review of Current Standards and Future Directions

BACKGROUND

Surgical resection for pancreatic ductal adenocarcinoma (PDAC) entails the excision of the primary tumour and regional lymphadenectomy. This traditional strategy is challenged by the high rate of early recurrence, suggesting inadequate disease staging. Novel methods of intra-operative staging are needed to allow surgical resection to be tailored to the disease's biology.

METHODS

A search of published articles on the PubMed and Embase databases was performed using the terms 'pancreas' OR 'pancreatic' AND 'intra-operative staging/detection' OR 'guided surgery'. Articles published between January 2000 and June 2023 were included. Technologies that offered intra-operative staging and tailored treatment were curated and summarised in the following integrative review.

RESULTS

lymph node (LN) mapping and radioimmunoguided surgery have shown promising results but lacked practicality to facilitate real-time intra-operative staging for PDAC. Fluorescence-guided surgery (FGS) offers high contrast and sensitivity, enabling the identification of cancerous tissue and positive LNs with improved precision following intravenous administration of a fluorescent agent. The unique properties of optical coherence tomography and ultrasound elastography lend themselves to be platforms for virtual biopsy intra-operatively.

CONCLUSIONS

Accurate intra-operative staging of PDAC, localisation of metastatic LNs, and identification of extra-pancreatic disease remain clinically unmet needs under current detection methods and staging standards. Tumour-specific FGS combined with other diagnostic and therapeutic modalities could improve tumour detection and staging in patients with PDAC.

Molecular Imaging Biomarkers for Early Cancer Detection: A Systematic Review of Emerging Technologies and Clinical Applications

BACKGROUND

Early cancer detection is crucial for improving patient outcomes. Molecular imaging biomarkers offer the potential for non-invasive, early-stage cancer diagnosis.

OBJECTIVES

To evaluate the effectiveness and accuracy of molecular imaging biomarkers for early cancer detection across various imaging modalities and cancer types.

METHODS

A comprehensive search of PubMed/MEDLINE, Embase, Web of Science, Cochrane Library, and Scopus was performed, covering the period from January 2010 to December 2023. Eligibility criteria included original research articles published in English on molecular imaging biomarkers for early cancer detection in humans. The risk of bias for included studies was evaluated using the QUADAS-2 tool. The findings were synthesized through narrative synthesis, with quantitative analysis conducted where applicable.

RESULTS

In total, 50 studies were included. Positron emission tomography (PET)-based biomarkers showed the highest sensitivity (mean: 89.5%, range: 82-96%) and specificity (mean: 91.2%, range: 85-100%). Novel tracers such as [68Ga]-PSMA for prostate cancer and [18F]-FES for breast cancer demonstrated promising outcomes. Optical imaging techniques showed high specificity in intraoperative settings.

CONCLUSIONS

Molecular imaging biomarkers show significant potential for improving early cancer detection. Integration into clinical practice could lead to earlier interventions and improved outcomes. Further research is needed to address standardization and cost-effectiveness.

Utility of Sodium Fluorescein During Peripheral Nerve Tumor Surgery: A Scoping Review of Indications, Techniques, and Outcomes

OBJECTIVE

The primary treatment for peripheral nerve tumors involves maximal surgical resection while preserving nerve function. Sodium fluorescein shows potential for enhancing the safety and efficacy of nerve tumor surgery. This review evaluates the advantages and limitations of sodium fluorescein in this context.

METHODS

PubMed, EMBASE, Web-of-Science, and Scopus were searched following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-scoping review guidelines to include studies reporting the use of sodium fluorescein in peripheral nerve tumors surgery. Intervention-related outcomes (i.e., extent of resection, clinical outcomes, complication rates, recurrence rates, and duration of surgery) were evaluated and summarized.

RESULTS

A total of 4 studies encompassing 166 patients with 168 tumors were included. Patients were mostly female (98; 53.6%), 101 (69.2%), had sporadic (nonsyndromic) tumors, and at histopathology, 114 (67.9%) tumors were WHO grade-1 schwannomas. Gross total resection was achieved in 146 (86.9%) tumors. Postoperative complications were reported in 16 cases (10.2%%), none related to side effects of the fluorescent dye. High tumor fluorescence was reported in 150 (94.3%) tumors, while absent and low parent nerve fluorescence was reported in 121 (79.6%) and 27 (17.8%), respectively. The median duration of surgery was 51.5 (range: 24-92) minutes.

CONCLUSIONS

Sodium fluorescein shows promise as assisting tool in nerve tumor surgery by facilitating differentiation among the tumor, parent nerve, and surrounding soft tissue. However, multicenter randomized controlled trials are necessary to determine its effect on extent of resection rates, clinical outcomes, postoperative complication rates, and surgical duration in comparison to current standard of care.

Development of Polar BODIPY-Tetrazines for Rapid Pretargeted Fluorescence Imaging

Polar BODIPY-tetrazine dyes were developed and clicked in vivo to a preaccumulated trans-cyclooctene-modified anti-TAG72 monoclonal antibody CC49 (CC49-TCO). The in vivo click performance was evaluated using an in-house developed ex vivo blocking assay. All tested polar BODIPY structures exhibited excellent in vivo binding, confirming that the turn-on tetrazine dyes successfully clicked in vivo to pretargeted CC49-TCO. Fluorescence imaging showed high tumor-to-muscle ratios of 4:1. This proof-of-concept study indicates that the pretargeting concept based on turn-on probes could be used for cancer treatments, such as photodynamic or -thermal therapy.

Fluorescence lifetime imaging unravels the pathway of glioma cell death upon hypericin-induced photodynamic therapy

Malignant primary brain tumors are a group of highly aggressive and often infiltrating tumors that lack adequate therapeutic treatments to achieve long time survival. Complete tumor removal is one precondition to reach this goal. A promising approach to optimize resection margins and eliminate remaining infiltrative so-called guerilla cells is photodynamic therapy (PDT) using organic photosensitizers that can pass the disrupted blood-brain-barrier and selectively accumulate in tumor tissue. Hypericin fulfills these conditions and additionally offers outstanding photophysical properties, making it an excellent choice as a photosensitizing molecule for PDT. However, the actual hypericin-induced PDT cell death mechanism is still under debate. In this work, hypericin-induced PDT was investigated by employing the three distinct fluorescent probes hypericin, resorufin and propidium iodide (PI) in fluorescence-lifetime imaging microscopy (FLIM). This approach enables visualizing the PDT-induced photodamaging and dying of single, living glioma cells, as an in vitro tumor model for glioblastoma. Hypericin PDT and FLIM image acquisition were simultaneously induced by 405 nm laser irradiation and sequences of FLIM images and fluorescence spectra were recorded to analyze the PDT progression. The reproducibly observed cellular changes provide insight into the mechanism of cell death during PDT and suggest that apoptosis is the initial mechanism followed by necrosis after continued irradiation. These new insights into the mechanism of hypericin PDT of single glioma cells may help to adjust irradiation doses and improve the implementation as a therapy for primary brain tumors.

Whole-body fluorescence cryotomography identifies a fast-acting, high-contrast, durable contrast agent for fluorescence-guided surgery

Imaging of tumor-specific fluorescent contrast agents to guide tumor removal has been shown to improve outcomes and is now standard practice for some neurosurgical procedures. However, many agents require administration hours before surgery, a practical challenge, and may exhibit inconsistent concordance with contrast-enhanced MRI (CE-MRI), the current standard for diagnosing and guiding glioma removal. A fluorescent agent that accurately marks tumor shortly after administration and is otherwise similar to CE-MRI would help overcome these shortcomings. Methods: We used whole-body 3-D fluorescence cryo-imaging and co-registered CE-MRI volumes to evaluate several fluorescent contrast agent candidates for diagnostic performance and concordance with CE-MRI. Mice with brain tumors were administered a cocktail of fluorescent agent candidates and a MRI contrast agent, and then imaged with MRI and fluorescence cryo-imaging at several timepoints after administration. The high-resolution 3-D cryo-imaging volumes of the fluorescent agents were used to determine diagnostic performance metrics and correlation with CE-MRI. Results: While all agents showed positive metrics, one agent, tetramethylrhodamine conjugated to a small polyethylene glycol chain (TMR-PEG1k), outperformed the others, exhibiting minimal normal brain signal, high tumor-to-background-ratio, diagnostic accuracy, and cross-correlation to CE-MRI at all post-administration timepoints (10-90 min) and tumor lines examined. Conclusion: These favorable properties establish TMR-PEG1k as a promising candidate for surgical guidance.

Nanotechnology in cancer therapeutics, diagnosis, and management

Nanotechnology presents an exciting opportunity in cancer research by offering significant advancements in therapies, diagnosis, and management. It possesses unparalleled potential to enhance the accuracy and effectiveness of cancer therapy while simultaneously reducing adverse effects, owing to its distinctive capability to manipulate matter at a molecular level. Using nanoparticle carriers has facilitated the precise administration of therapeutic agents to afflicted areas within the human body through customized drug delivery systems, resulting in improved treatment accuracy and efficacy while reducing adverse effects. These techniques improve drug solubility and stability, leading to elevated levels of biochemical availability and improved efficacy outcomes for patients with minimal negative effects during treatment cycles. Another use case for nanoparticles includes tumor imaging; functionalized with targeting ligands containing diagnostic agents, they foster early detection, making quicker remedial action plans possible. Overall, the incorporation of nanotechnology ensures a promising future, although it stresses the need to address regulatory hurdles and safety concerns before widespread clinical implementation. Despite the complexity of cancer research and patient care, nanotechnology shows promise in transforming both fields.

Evaluation of a bimodal, matched pair theranostic agent targeting prostate-specific membrane antigen

BACKGROUND

Prostate cancer affects 1 in 6 men, and it is the second‑leading cause of cancer-related death in American men. Surgery is one of the main treatment modalities for prostate cancer, but it often results in incomplete resection margins or complete resection that leads to nerve damage and undesirable side effects. In the present work, we have developed a new bimodal tracer, NODAGA-sCy7.5 PSMAi (prostate-specific membrane antigen inhibitor), labeled with the true matched theranostic pair 64Cu/67Cu and a near-infrared fluorescent dye. This agent could potentially be used for concomitant PET imaging, optical surgical navigation, and targeted radiopharmaceutical therapy.

METHODS

A prostate-specific membrane antigen (PSMA)-targeting urea derivative was conjugated to NODAGA for copper radiolabeling and to the near-infrared fluorophore sulfo-Cy7.5 (sCy7.5). Binding studies were performed in PSMA-positive PC-3 PIP cells, as well as uptake and internalization assays in PC-3 PIP cells and PSMA-negative PC-3 wild type cells. Biodistribution studies of the 64Cu-labeled compound were performed in PC-3 PIP- and PC-3 tumor-bearing mice, and 67Cu biodistributions of the agent were obtained in PC-3 PIP tumor-carrying mice. PET imaging and fluorescence imaging were also performed, using the same molar doses, in the two mouse models.

RESULTS

The PSMA conjugate bound with high affinity to PSMA-positive prostate cancer cells, as opposed to cells that were PSMA-negative. Uptake and internalization were rapid and PSMA-mediated in PC-3 PIP cells, while only minimal non-specific uptake was observed in PC-3 cells. Biodistribution studies showed specific uptake in PC-3 PIP tumors, while accumulation in PC-3 tumor-bearing mice was low. Furthermore, tumor uptake of the 67Cu-labeled agent in the PC-3 PIP model was statistically equivalent to that of 64Cu. PET and fluorescence imaging at 0.5 nmol per mouse also demonstrated that PC-3 PIP tumors could be clearly detected, while PC-3 tumors showed no tumor accumulation.

CONCLUSIONS

NODAGA-sCy7.5-PSMAi was specific and selective in detecting PSMA-positive, as opposed to PSMA-negative, tumors in mouse models of prostate cancer. This bioconjugate could potentially be used for PET staging with 64Cu, targeted radiopharmaceutical therapy with 67Cu, and/or image-guided surgery with sCy7.5.

A pan-cancer dye for solid-tumour screening, resection and wound monitoring via short-wave and near-infrared fluorescence imaging

The efficacy of fluorescence-guided surgery in facilitating the real-time delineation of tumours depends on the optical contrast of tumour tissue over healthy tissue. Here we show that CJ215-a commercially available, renally cleared carbocyanine dye sensitive to apoptosis, and with an absorption and emission spectra suitable for near-infrared fluorescence imaging (wavelengths of 650-900 nm) and shortwave infrared (SWIR) fluorescence imaging (900-1,700 nm)-can facilitate fluorescence-guided tumour screening, tumour resection and the assessment of wound healing. In tumour models of either murine or human-derived breast, prostate and colon cancers and of fibrosarcoma, and in a model of intraperitoneal carcinomatosis, imaging of CJ215 with ambient light allowed for the delineation of nearly all tumours within 24 h after intravenous injection of the dye, which was minimally taken up by healthy organs. At later timepoints, CJ215 provided tumour-to-muscle contrast ratios up to 100 and tumour-to-liver contrast ratios up to 18. SWIR fluorescence imaging with the dye also allowed for quantifiable non-contact wound monitoring through commercial bandages. CJ215 may be compatible with existing and emerging clinical solutions.

Intraoperative Imaging Techniques in Oncology

Imaging-based procedures have become well integrated into the diagnosis and management of oncological patients and play a significant role in reducing morbidity and mortality rates. Here we describe the established and upcoming surgical oncological imaging techniques and their impact on cancer management.

A Concept for Preoperative and Intraoperative Molecular Imaging and Detection for Assessing Extent of Disease of Solid Tumors

The authors propose a concept of "systems engineering," the approach to assessing the extent of diseased tissue (EODT) in solid tumors. We modeled the proof of this concept based on our clinical experience with colorectal carcinoma (CRC) and gastrinoma that included short and long-term survival data of CRC patients. This concept, applicable to various solid tumors, combines resources from surgery, nuclear medicine, radiology, pathology, and oncology needed for preoperative and intraoperative assessments of a patient's EODT. The concept begins with a patient presenting with biopsy-proven cancer. An appropriate preferential locator (PL) is a molecule that preferentially binds to a cancer-related molecular target (i.e., tumor marker) lacking in non-malignant tissue and is the essential element. Detecting the PL after an intravenous injection requires the PL labeling with an appropriate tracer radionuclide, a fluoroprobe, or both. Preoperative imaging of the tracer's signal requires molecular imaging modalities alone or in combination with computerized tomography (CT). These include positron emission tomography (PET), PET/CT, single-photon emission computed tomography (SPECT), SPECT/CT for preoperative imaging, gamma cameras for intraoperative imaging, and gamma-detecting probes for precise localization. Similarly, fluorescent-labeled PLs require appropriate cameras and probes. This approach provides the surgeon with real-time information needed for R0 resection.

Detection of Residual Peritoneal Metastases Following Cytoreductive Surgery Using Pegsitacianine, a pH-Sensitive Imaging Agent: Final Results from a Phase II Study

BACKGROUND

For patients with peritoneal carcinomatosis, extent of disease and completeness of cytoreductive surgery (CRS) are major prognostic factors for long-term survival. Assessment of these factors could be improved using imaging agents. Pegsitacianine is a pH-sensitive polymeric micelle conjugated to the fluorophore indocyanine green. The micelle disassembles in acidic microenvironments, such as tumors, resulting in localized fluorescence unmasking. We assessed the utility of pegsitacianine in detecting residual disease following CRS.

PATIENTS AND METHODS

NCT04950166 was a phase II, non-randomized, open-label, multicenter US study. Patients eligible for CRS were administered an intravenous dose of pegsitacianine at 1 mg/kg 24-72 h before surgery. Following CRS, the peritoneal cavity was reexamined under near-infrared (NIR) illumination to evaluate for fluorescent tissue. Fluorescent tissue identified was excised and evaluated by histopathology. The primary outcome was the rate of clinically significant events (CSE), defined as detection of histologically confirmed residual disease excised with pegsitacianine or a revision in the assessment of completeness of CRS. Secondary outcomes included acceptable safety and pegsitacianine performance.

RESULTS

A total of 53 patients were screened, 50 enrolled, and 40 were evaluable for CSE across six primary tumor types. Residual disease was detected with pegsitacianine in 20 of 40 (50%) patients. Pegsitacianine showed high sensitivity and was well tolerated with no serious adverse events (SAEs). Transient treatment-related, non-anaphylactic infusion reactions occurred in 28% of patients.

CONCLUSIONS

Pegsitacianine was well tolerated and facilitated the recognition of occult residual disease following CRS. The high rate of residual disease detected suggests that the use of pegsitacianine augmented surgeon assessment and performance during CRS.

Fluorescence in neurosurgery: its therapeutic and diagnostic significance - a comprehensive review

This review provides a comprehensive overview of the therapeutic and diagnostic implications of fluorescence imaging in neurosurgery. Fluorescence imaging has become a valuable intraoperative visualization and guidance tool, facilitating precise surgical interventions. The therapeutic role of fluorescence is examined, including its application in photodynamic therapy and tumor-targeted therapy. It also explores its diagnostic capabilities in tumor detection, margin assessment, and blood-brain barrier evaluation. Drawing from clinical and preclinical studies, the review underscores the growing evidence supporting the efficacy of fluorescence imaging in neurosurgical practice. Furthermore, it discusses current limitations and future directions, emphasizing the potential for emerging technologies to enhance the utility and accessibility of fluorescence imaging, ultimately improving patient outcomes in neurosurgery.

Intraoperative fluorescence redefining neurosurgical precision

Surgical resection is essential for treating solid tumors, with success largely dependent on the complete excision of neoplastic cells. However, neurosurgical procedures must delicately balance tumor removal with the preservation of surrounding tissue. Achieving clear margins is particularly challenging in cases like glioblastoma due to the limitations of traditional white light visualization. These limitations often result in incomplete resections, leading to frequent recurrences, or excessive resection that harms vital neural structures, causing iatrogenic nerve damage which can lead to sensory and functional deficits. Current statistics reveal a 90% recurrence rate for malignant gliomas. Similarly, an 8% incidence of iatrogenic nerve trauma contributes to an estimated 25 million cases of peripheral nerve injury globally each year. These figures underscore the urgent need for improved intraoperative techniques for lesion margin and nerve identification and visualization. Recent advances in neurosurgical imaging, such as fluorescence-guided surgery (FGS), have begun to address these challenges. Fluorescent agents used in FGS illuminate target tissues, although not all do so selectively. Despite the promising results of agents such as 5-aminolevulinic acid and indocyanine green, their applications are mainly limited by issues of sensitivity and specificity. Furthermore, these agents do not effectively address the need for precise nerve visualization. Nerve Peptide 41, a novel systemically administered fluorescent nerve-targeted probe, shows promise in filling this gap. This review assesses the major fluorescent imaging modalities in neurosurgery, highlighting each of their benefits, limitations, and potential.

DOTA-Based Plectin-1 Targeted Contrast Agent Enables Detection of Pancreatic Cancer in Human Tissue

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and lethal malignancy with extremely poor patient survival rates. A key reason for the poor prognosis is the lack of effective diagnostic tools to detect the disease at curable, premetastatic stages. Tumor surgical resection is PDAC's first-line treatment, however distinguishing between cancerous and healthy tissue with current imaging tools remains a challenge. In this work, we report a DOTA-based fluorescent probe targeting plectin-1 for imaging PDAC with high specificity. To enable heterogeneous functionalization of the DOTA-core with multiple targeting peptide units and the fluorophore, a novel, fully clickable synthetic route that proceeds in one pot was developed. Extensive validation of the probe set the stage for PDAC detection in mice and human tissue. Altogether, these findings may pave the way for improved clinical understanding and early detection of PDAC progression as well as more accurate resection criteria.

Real-time identification of life-threatening necrotizing soft-tissue infections using indocyanine green fluorescence imaging

Significance

Necrotizing soft-tissue infections (NSTIs) are life-threatening infections with a cumulative case fatality rate of 21%. The initial presentation of an NSTI is non-specific, frequently leading to misdiagnosis and delays in care. No current strategies yield an accurate, real-time diagnosis of an NSTI.

Aim

A first-in-kind, observational, clinical pilot study tested the hypothesis that measurable fluorescence signal voids occur in NSTI-affected tissues following intravenous administration and imaging of perfusion-based indocyanine green (ICG) fluorescence. This hypothesis is based on the established knowledge that NSTI is associated with local microvascular thrombosis.

Approach

Adult patients presenting to the Emergency Department of a tertiary care medical center at high risk for NSTI were prospectively enrolled and imaged with a commercial fluorescence imager. Single-frame fluorescence snapshot and first-pass perfusion kinetic parameters-ingress slope (IS), time-to-peak (TTP) intensity, and maximum fluorescence intensity (IMAX)-were quantified using a dynamic contrast-enhanced fluorescence imaging technique. Clinical variables (comorbidities, blood laboratory values), fluorescence parameters, and fluorescence signal-to-background ratios (SBRs) were compared to final infection diagnosis.

Results

Fourteen patients were enrolled and imaged (six NSTI, six cellulitis, one diabetes mellitus-associated gangrene, and one osteomyelitis). Clinical variables demonstrated no statistically significant differences between NSTI and non-NSTI patient groups (p -value ≥ 0.22 ). All NSTI cases exhibited prominent fluorescence signal voids in affected tissues, including tissue features not visible to the naked eye. All cellulitis cases exhibited a hyperemic response with increased fluorescence and no distinct signal voids. Median lesion-to-background tissue SBRs based on snapshot, IS, TTP, and IMAX parameter maps ranged from 3.2 to 9.1, 2.2 to 33.8, 1.0 to 7.5, and 1.5 to 12.7, respectively, for the NSTI patient group. All fluorescence parameters except TTP demonstrated statistically significant differences between NSTI and cellulitis patient groups (p -value < 0.05 ).

Conclusions

Real-time, accurate discrimination of NSTIs compared with non-necrotizing infections may be possible with perfusion-based ICG fluorescence imaging.

Indocyanine green fluorescence applied to gynecologic oncology: beyond sentinel lymph node

Indocyanine green (ICG), a well-known molecule employed in medicine for over five decades, has emerged as a versatile dye widely embraced across various surgical disciplines. In gynecologic oncology, its prevalent use revolves around the detection of sentinel lymph nodes. However, the true potential of ICG extends beyond this singular application, owing to its pragmatic utility, cost-effectiveness, and safety profile. Furthermore, ICG has been introduced in the theranostic landscape, marking a significant juncture in the evolution of its clinical utility. This narrative review aims to describe the expanding horizons of ICG fluorescence in gynecologic oncology, beyond the sentinel lymph node biopsy. The manifold applications reported within this manuscript include: 1) lymphography; 2) angiography; 3) nerve visualization; 4) ICG-driven resections; and 5) theranostic. The extensive exploration across these numerous applications, some of which are still in the preclinical phase, serves as a hypothesis generator, aiming to stimulate the development of clinical studies capable of expanding the use of this drug in our field, enhancing the care of gynecological cancer patients.

Trimeric and Tetrameric Cationic Styryl Dyes as Novel Fluorescence and CD Probes for ds-DNA and ds-RNA

The wide use of mono- or bis-styryl fluorophores in biomedical applications prompted the presented design and study of a series of trimeric and tetrameric homo-analogues, styryl moieties arranged around a central aromatic core. The interactions with the most common biorelevant targets, ds-DNA and ds-RNA, were studied by a set of spectrophotometric methods (UV-VIS, fluorescence, circular dichroism, thermal denaturation). All studied dyes showed strong light absorption in the 350-420 nm range and strongly Stokes-shifted (+100-160 nm) emission with quantum yields (Φf) up to 0.57, whereby the mentioned properties were finely tuned by the type of the terminal cationic substituent and number of styryl components (tetramers being red-shifted in respect to trimers). All studied dyes strongly interacted with ds-DNA and ds-RNA with 1-10 nM-1 affinity, with dye emission being strongly quenched. The tetrameric analogues did not show any particular selectivity between ds-DNA or ds-RNA due to large size and consequent partial, non-selective insertion into DNA/RNA grooves. However, smaller trimeric styryl series showed size-dependent selective stabilization of ds-DNA vs. ds-RNA against thermal denaturation and highly selective or even specific recognition of several particular ds-DNA or ds-RNA structures by induced circular dichroism (ICD) bands. The chiral (ICD) selectivity was controlled by the size of a terminal cationic substituent. All dyes entered efficiently live human cells with negligible cytotoxic activity. Further prospects in the transfer of ICD-based selectivity into fluorescence-chiral methods (FDCD and CPL) is proposed, along with the development of new analogues with red-shifted absorbance properties.

eTFC-01: a dual-labeled chelate-bridged tracer for SSTR2-positive tumors

BACKGROUND

Integrating radioactive and optical imaging techniques can facilitate the prognosis and surgical guidance for cancer patients. Using a single dual-labeled tracer ensures consistency in both imaging modalities. However, developing such molecule is challenging due to the need to preserve the biochemical properties of the tracer while introducing bulky labeling moieties. In our study, we designed a trifunctional chelate that facilitates the coupling of the targeting vector and fluorescent dye at opposite sites to avoid undesired steric hindrance effects. The synthesis of the trifunctional chelate N3-Py-DOTAGA-(tBu)3 (7) involved a five-step synthetic route, followed by conjugation to the linear peptidyl-resin 8 through solid-phase synthesis. After deprotection and cyclization, the near-infrared fluorescent dye sulfo-Cy.5 was introduced using copper free click chemistry, resulting in eTFC-01. Subsequently, eTFC-01 was labeled with [111In]InCl3. In vitro assessments of eTFC-01 binding, uptake, and internalization were conducted in SSTR2-transfected U2OS cells. Ex-vivo biodistribution and fluorescence imaging were performed in H69-tumor bearing mice.

RESULTS

eTFC-01 demonstrated a two-fold higher IC50 value for SSTR2 compared to the gold standard DOTA-TATE. Labeling of eTFC-01 with [111In]InCl3 gave a high radiochemical yield and purity. The uptake of [111In]In-eTFC-01 in U2OS.SSTR2 cells was two-fold lower than the uptake of [111In]In-DOTA-TATE, consistent with the binding affinity. Tumor uptake in H69-xenografted mice was lower for [111In]In-eTFC-01 at all-time points compared to [111In]In-DOTA-TATE. Prolonged blood circulation led to increased accumulation of [111In]In-eTFC-01 in highly vascularized tissues, such as lungs, skin, and heart. Fluorescence measurements in different organs correlated with the radioactive signal distribution.

CONCLUSION

The successful synthesis and coupling of the trifunctional chelate to the peptide and fluorescent dye support the potential of this synthetic approach to generate dual labeled tracers. While promising in vitro, the in vivo results obtained with [111In]In-eTFC-01 suggest the need for adjustments to enhance tracer distribution.

A review of recent advances in the use of complex metal nanostructures for biomedical applications from diagnosis to treatment

Complex metal nanostructures represent an exceptional category of materials characterized by distinct morphologies and physicochemical properties. Nanostructures with shape anisotropies, such as nanorods, nanostars, nanocages, and nanoprisms, are particularly appealing due to their tunable surface plasmon resonances, controllable surface chemistries, and effective targeting capabilities. These complex nanostructures can absorb light in the near-infrared, enabling noteworthy applications in nanomedicine, molecular imaging, and biology. The engineering of targeting abilities through surface modifications involving ligands, antibodies, peptides, and other agents potentiates their effects. Recent years have witnessed the development of innovative structures with diverse compositions, expanding their applications in biomedicine. These applications encompass targeted imaging, surface-enhanced Raman spectroscopy, near-infrared II imaging, catalytic therapy, photothermal therapy, and cancer treatment. This review seeks to provide the nanomedicine community with a thorough and informative overview of the evolving landscape of complex metal nanoparticle research, with a specific emphasis on their roles in imaging, cancer therapy, infectious diseases, and biofilm treatment. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Diagnostic Tools > Diagnostic Nanodevices.

Automated online safety margin (GLIOVIS) for glioma surgery model

Purpose

Glioblastoma is the most common type of primary brain malignancy and has a poor prognosis. The standard treatment strategy is based on maximal safe surgical resection followed by radiotherapy and chemotherapy. Surgical resection can be optimized by using 5-delta-aminolevulinic acid (5-ALA)-induced fluorescence, which is the current mainstay. Although 5-ALA-induced fluorescence has gained general acceptance, it is also limited by inter-observer variability and non-standardized fluorescence parameters. We present a new software for processing images analysis to better recognize the tumor infiltration margins using an intraoperative immediate safety map of 5-ALA-induced fluorescence. We tested this in a brain model using a commercial surgical exoscope.

Methods

A dedicated software GLIOVIS (ACQuF-II, Advanced Colorimetry-based Quantification of Fluorescence) was designed for processing analysis of images taken on the Intraoperative Orbital Camera Olympus Orbeye (IOC) to determine the relative quantification of Protoporphyrin IX (5-ALA metabolite) fluorescence. The software allows to superpose the new fluorescence intensity map and the safety margins over the original images. The software was tested on gel-based brain models.

Results

Two surrogate models were developed: PpIX agarose gel-integrated in gelatin-based brain model at different scales (1:25 and 1:1). The images taken with the IOC were then processed using GLIOVIS. The intensity map and safety margins could be obtained for all available models.

Conclusions

GLIOVIS for 5-ALA-guided surgery image processing was validated on various gelatin-based brain models. Different levels of fluorescence could be qualitatively digitalized using this technique. These results need to be further confirmed and corroborated in vivo and validated clinically in order to define a new standard of care for glioblastoma resection.

Preoperative three-dimensional modelling and virtual reality planning aids nephron sparing surgery in a child with bilateral Wilms tumour

Bilateral Wilms tumour (BWT) is a surgically challenging condition. Virtual reality (VR) reconstruction aids surgeons to foresee the anatomy ahead of Nephron Sparing Surgery (NSS). Three-dimensional (3D) visualisation improves the anatomical orientation of surgeons performing NSS. We herewith report a case of BWT where VR planning and 3D printing were used to aid NSS. Conventional imaging is often found to be inadequate while assessing the tumour-organ-vascular anatomy. Advances like VR and 3D printing help surgeons plan better for complex surgeries like bilateral NSS. Next-generation extended reality tools will likely aid robotic-assisted precision NSS and improve patient outcomes.

Activity-Based Fluorescence Diagnostics for Cancer

Fluorescence imaging is one of the most promising approaches to achieve intraoperative assessment of the tumor/normal tissue margins during cancer surgery. This is critical to improve the patients' prognosis, and therefore various molecular fluorescence imaging probes have been developed for the identification of cancer lesions during surgery. Among them, "activatable" fluorescence probes that react with cancer-specific biomarker enzymes to generate fluorescence signals have great potential for high-contrast cancer imaging due to their low background fluorescence and high signal amplification by enzymatic turnover. Over the past two decades, activatable fluorescence probes employing various fluorescence control mechanisms have been developed worldwide for this purpose. Furthermore, new biomarker enzymatic activities for specific types of cancers have been identified, enabling visualization of various types of cancers with high sensitivity and specificity. This Review focuses on recent advances in the design, function and characteristics of activatable fluorescence probes that target cancer-specific enzymatic activities for cancer imaging and also discusses future prospects in the field of activity-based diagnostics for cancer.

Self-Disassembling and Oxygen-Generating Porphyrin-Lipoprotein Nanoparticle for Targeted Glioblastoma Resection and Enhanced Photodynamic Therapy

The dismal prognosis for glioblastoma multiform (GBM) patients is primarily attributed to the highly invasive tumor residual that remained after surgical intervention. The development of precise intraoperative imaging and postoperative residual removal techniques will facilitate the gross total elimination of GBM. Here, a self-disassembling porphyrin lipoprotein-coated calcium peroxide nanoparticles (PLCNP) is developed to target GBM via macropinocytosis, allowing for fluorescence-guided surgery of GBM and improving photodynamic treatment (PDT) of GBM residual by alleviating hypoxia. By reducing self-quenching and enhancing lysosome escape efficiency, the incorporation of calcium peroxide (CaO2) cores in PLCNP amplifies the fluorescence intensity of porphyrin-lipid. Furthermore, the CaO2 core has diminished tumor hypoxia and improves the PDT efficacy of PLCNP, enabling low-dose PDT and reversing tumor progression induced by hypoxia aggravation following PDT. Taken together, this self-disassembling and oxygen-generating porphyrin-lipoprotein nanoparticle may serve as a promising all-in-one nanotheranostic platform for guiding precise GBM excision and empowering post-operative PDT, providing a clinically applicable strategy to combat GBM in a safe and effective manner.

Advancement of fluorescent aminopeptidase probes for rapid cancer detection-current uses and neurosurgical applications

Surgical resection is considered for most brain tumors to obtain tissue diagnosis and to eradicate or debulk the tumor. Glioma, the most common primary malignant brain tumor, generally has a poor prognosis despite the multidisciplinary treatments with radical resection and chemoradiotherapy. Surgical resection of glioma is often complicated by the obscure border between the tumor and the adjacent brain tissues and by the tumor's infiltration into the eloquent brain. 5-aminolevulinic acid is frequently used for tumor visualization, as it exhibits high fluorescence in high-grade glioma. Here, we provide an overview of the fluorescent probes currently used for brain tumors, as well as those under development for other cancers, including HMRG-based probes, 2MeSiR-based probes, and other aminopeptidase probes. We describe our recently developed HMRG-based probes in brain tumors, such as PR-HMRG, combined with the existing diagnosis approach. These probes are remarkably effective for cancer cell recognition. Thus, they can be potentially integrated into surgical treatment for intraoperative detection of cancers.

Monoclonal Antibodies for Targeted Fluorescence-Guided Surgery: A Review of Applicability across Multiple Solid Tumors

This study aims to review the status of the clinical use of monoclonal antibodies (mAbs) that have completed or are in ongoing clinical trials for targeted fluorescence-guided surgery (T-FGS) for the intraoperative identification of the tumor margins of extra-hematological solid tumors. For each of them, the targeted antigen, the mAb generic/commercial name and format, and clinical indications are presented, together with utility, doses, and the timing of administration. Based on the current scientific evidence in humans, the top three mAbs that could be prepared in a GMP-compliant bank ready to be delivered for surgical purposes are proposed to speed up the translation to the operating room and produce a few readily available "off-the-shelf" injectable fluorescent probes for safer and more effective solid tumor resection.

Fluorescence guided surgery imaging systems for breast cancer identification: a systematic review

Significance

Breast-conserving surgery (BCS) is limited by high rates of positive margins and re-operative interventions. Fluorescence-guided surgery seeks to detect the entire lesion in real time, thus guiding the surgeons to remove all the tumor at the index procedure.

Aim

Our aim was to identify the optimal combination of a camera system and fluorophore for fluorescence-guided BCS.

Approach

A systematic review of medical databases using the terms "fluorescence," "breast cancer," "surgery," and "fluorescence imaging" was performed. Cameras were compared using the ratio between the fluorescent signal from the tumor compared to background fluorescence, as well as diagnostic accuracy measures, such as sensitivity, specificity, and positive predictive value.

Results

Twenty-one studies identified 14 camera systems using nine different fluorophores. Twelve cameras worked in the infrared spectrum. Ten studies reported on the difference in strength of the fluorescence signal between cancer and normal tissue, with results ranging from 1.72 to 4.7. In addition, nine studies reported on whether any tumor remained in the resection cavity (5.4% to 32.5%). To date, only three studies used the fluorescent signal for guidance during real BCS. Diagnostic accuracy ranged from 63% to 98% sensitivity, 32% to 97% specificity, and 75% to 100% positive predictive value.

Conclusion

In this systematic review, all the studies reported a clinically significant difference in signal between the tumor and normal tissue using various camera/fluorophore combinations. However, given the heterogeneity in protocols, including camera setup, fluorophore studied, data acquisition, and reporting structure, it was impossible to determine the optimal camera and fluorophore combination for use in BCS. It would be beneficial to develop a standardized reporting structure using similar metrics to provide necessary data for a comparison between camera systems.

Multicolor fluorescence microscopy for surgical guidance using a chip-scale imager with a low-NA fiber optic plate and a multi-bandpass interference filter

In curative-intent cancer surgery, intraoperative fluorescence imaging of both diseased and healthy tissue can help to ensure the successful removal of all gross and microscopic diseases with minimal damage to neighboring critical structures, such as nerves. Current fluorescence-guided surgery (FGS) systems, however, rely on bulky and rigid optics that incur performance-limiting trade-offs between sensitivity and maneuverability. Moreover, many FGS systems are incapable of multiplexed imaging. As a result, clinical FGS is currently limited to millimeter-scale detection of a single fluorescent target. Here, we present a scalable, lens-less fluorescence imaging chip, VISION, capable of sensitive and multiplexed detection within a compact form factor. Central to VISION is a novel optical frontend design combining a low-numerical-aperture fiber optic plate (LNA-FOP) and a multi-bandpass interference filter, which is affixed to a custom CMOS image sensor. The LNA-FOP acts as a planar collimator to improve resolution and compensate for the angle-sensitivity of the interference filter, enabling high-resolution and multiplexed fluorescence imaging without lenses. We show VISION is capable of detecting tumor foci of less than 100 cells at near video framerates and, as proof of principle, can simultaneously visualize both tumors and nerves in ex vivo prostate tissue.

Translocator Protein 18 kDa (TSPO): A Promising Molecular Target for Image-Guided Surgery of Solid Cancers

The translocator protein 18-kDa (TSPO) is a mitochondrial membrane protein that is previously identified as the peripheral benzodiazepine receptor (PBR). Furthermore, it plays a significant role in a diverse range of biochemical processes, including steroidogenesis, mitochondrial cholesterol transport, cell survival and death, cell proliferation, and carcinogenesis. Several investigations also reported its roles in various types of cancers, including colorectal, brain, breast, prostate, and lung cancers, as well as melanoma. According to a previous study, the expression of TSPO was upregulated in cancer cells, which corresponds to an aggressive phenotype and/or poor prognosis. Consequently, the potential for crafting diagnostic and prognostic tools with a focus on TSPO holds great potential. In this context, several radioligands designed to target this protein have been identified, and some of the candidates have advanced to clinical trials. In recent years, the use of hybrid probes with radioactive and fluorescence molecules for image-guided surgery has exhibited promising results in animal and human studies. This indicates that the approach can serve as a valuable surgical navigator during cancer surgery. The current hybrid probes are built from various molecular platforms, including small molecules, nanoparticles, and antibodies. Although several TSPO-targeted imaging probes have been developed, their development for image-guided surgery of cancers is still limited. Therefore, this review aims to highlight recent findings on the involvement of TSPO in carcinogenesis, as well as provide a new perspective on the potential application of TSPO-targeted hybrid probes for image-guided surgery.

Multicolor fluorescence microscopy for surgical guidance using a chip-scale imager with a low-NA fiber optic plate and a multi-bandpass interference filter

In curative-intent cancer surgery, intraoperative fluorescence imaging of both diseased and healthy tissue can help to ensure successful removal of all gross and microscopic disease with minimal damage to neighboring critical structures, such as nerves. Current fluorescence-guided surgery (FGS) systems, however, rely on bulky and rigid optics that incur performance-limiting trade-offs between sensitivity and maneuverability. Moreover, many FGS systems are incapable of multiplexed imaging. As a result, clinical FGS is currently limited to millimeter-scale detection of a single fluorescent target. Here we present a scalable, lens-less fluorescence imaging chip, VISION, capable of sensitive and multiplexed detection within a compact form factor. Central to VISION is a novel optical frontend design combining a low-numerical-aperture fiber optic plate (LNA-FOP) and a multi-bandpass interference filter, which is affixed to a custom CMOS image sensor. The LNA-FOP acts as a planar collimator to improve resolution and compensate for the angle-sensitivity of the interference filter, enabling high-resolution and multiplexed fluorescence imaging without lenses. We show VISION is capable of detecting tumor foci of less than 100 cells at near video framerates and, as proof of principle, can simultaneously visualize both tumor and nerves in ex vivo prostate tissue.

Enhancing visualization and guidance in general surgery: a comprehensive and narrative review of the current cutting-edge technologies and future perspectives

BACKGROUND

In the last decade, there has been a great effort in developing new technologies to enhance surgical visualization and guidance. This comprehensive and narrative review aimed to provide a wide and extensive overview of the current state of the art on this topic and their near-future perspectives linked to the development of artificial intelligence (AI), by focusing on the most recent and relevant literature.

METHODS

A comprehensive and narrative review of the literature was performed by searching specific terms on PubMed/MEDLINE, Scopus, and Embase databases, assessing the current state of the art on this topic.

RESULTS

Fluorescence-guided surgery, contrast-enhanced ultrasound (CEUS), ultra-high frequency ultrasound (UHFUS), photoacoustic imaging (PAI), and augmented reality (AR) are boosting the field of image-guided techniques as the rapid development of AI in surgery is promising a more automated decision-making and surgical movements in the operating room.

CONCLUSION

Fluorescence-guided surgery, CEUS, UHFUS, PAI, and AR are becoming crucial to give surgeons a new level of information during the intervention, with the right timing and sequence, and represent the future of surgery. As many more controlled studies are needed to validate the employment of these technologies, the next generation of surgeons must become more familiar with the basics of AI to better incorporate new tools into the daily surgical practice of the future.

Fluorescence visualization for cancer DETECTION: EXPERIENCE and perspectives

The current review focuses on the latest advances in the improvement and application of fluorescence imaging technology. Near-infrared (NIR) fluorescence imaging is a promising new technique that uses non-specific fluorescent agents and targeted fluorescent tracers combined with a dedicated camera to better navigate and visualize tumors. Fluorescence-guided surgery (FGS) is used to perform various tasks, helping the surgeon to distinguish lymphatic vessels and nodes from surrounding tissues easily and quickly assess the perfusion of the planned resection area, including intraoperative visualization of metastases. The results of the insertion of fluorescence visualization as an auxiliary method to cancer detection and high-risk metastatic lesions in clinical practice have demonstrated enthusiastic results and huge potential. However, intraoperative fluorescence visualization must not be considered as a main diagnostic or treatment method but as an aid to the surgeon. Thus, fluorescence study does not dispense the diagnostic gold standards of benign or malignant tumors (conventional examination, biopsy, ultrasonography and computed tomography, etc.) and can be done usually during intraoperative treatment. Moreover, as fluorescence surgery and fluorescence diagnostic techniques continue to improve, it is likely that they will evolve towards targeted fluorescence imaging probes that will increasingly target a specific type of cancer cell. The most important point remains the search for highly selective messengers of fluorescent labels, which make it possible to identify tumor cells exclusively in the affected organs and indicate to surgeons the boundaries of their spread and metastasis.

Nanocrystals for Deep-Tissue In Vivo Luminescence Imaging in the Near-Infrared Region

In vivo imaging technologies have emerged as a powerful tool for both fundamental research and clinical practice. In particular, luminescence imaging in the tissue-transparent near-infrared (NIR, 700-1700 nm) region offers tremendous potential for visualizing biological architectures and pathophysiological events in living subjects with deep tissue penetration and high imaging contrast owing to the reduced light-tissue interactions of absorption, scattering, and autofluorescence. The distinctive quantum effects of nanocrystals have been harnessed to achieve exceptional photophysical properties, establishing them as a promising category of luminescent probes. In this comprehensive review, the interactions between light and biological tissues, as well as the advantages of NIR light for in vivo luminescence imaging, are initially elaborated. Subsequently, we focus on achieving deep tissue penetration and improved imaging contrast by optimizing the performance of nanocrystal fluorophores. The ingenious design strategies of NIR nanocrystal probes are discussed, along with their respective biomedical applications in versatile in vivo luminescence imaging modalities. Finally, thought-provoking reflections on the challenges and prospects for future clinical translation of nanocrystal-based in vivo luminescence imaging in the NIR region are wisely provided.