Fluorescence-guided Surgery Research Articles

Synthesis, Preclinical Evaluation, and First-in-Human Assessment of ICG-PSMA-D5: A PSMA-Targeted Probe for Fluorescence-Guided Surgery of Prostate Cancer.

Precise surgical resection of prostate cancer (PCa) is a significant clinical challenge due to the impact of positive surgical margins on postoperative outcomes. Fluorescence-guided surgery (FGS) enables real-time tumor visualization using fluorescent probes. In this study, we synthesized and evaluated an indocyanine green (ICG)-based PSMA-targeted near-infrared probe, ICG-PSMA-D5, for intraoperative imaging of PCa lesions. Spectroscopic analysis revealed that ICG-PSMA-D5 retained the optical properties of ICG while improving solubility in PBS due to additional carboxyl groups. In vitro assays demonstrated high binding affinity (Ki = 0.39 nM) and minimal cytotoxicity. In vivo studies in tumor-bearing mice showed strong tumor targeting, extended retention at tumor site, and favorable biodistribution, with significant tumor-to-background ratios. The first-in-human study in a patient with localized PCa indicated the probe's potential for real-time, radiation-free surgical guidance. Overall, ICG-PSMA-D5 displayed excellent performance in tumor detection and margin delineation, making it a promising candidate for intraoperative FGS in PCa.

Metabolomic characterisation of the glioblastoma invasive margin reveals a region-specific signature.

Isocitrate dehydrogenase wild-type glioblastoma (GBM) is characterised by a heterogeneous genetic landscape resulting from dynamic competition between tumour subclones to survive selective pressures. Improvements in metabolite identification and metabolome coverage have led to increased interest in clinically relevant applications of metabolomics. Here, we use liquid chromatography-mass spectrometry and gene expression microarray to profile integrated intratumour metabolic heterogeneity, as a direct functional readout of adaptive responses of subclones to the tumour microenvironment. Multi-region surgical sampling was performed on five adult GBM patients based on pre-operative brain imaging and fluorescence-guided surgery. Polar and hydrophobic metabolites extracted from tumour fragments were assessed, followed by putative assignment of metabolite identifications based on retention times and molecular mass. Class discrimination between tumour regions through showed clear separation of tumour regions based on polar metabolite profiles. Metabolic pathway assignments revealed several significantly altered metabolites between the tumour core and invasive region to be associated with purine and pyrimidine metabolism. This proof-of-principle study assesses intratumour heterogeneity through mass spectrometry-based metabolite profiling of multi-region biopsies. Bioinformatic interpretation of the GBM metabolome has highlighted the invasive region to be biologically distinct compared to tumour core and revealed putative drug-targetable metabolic pathways associated with purine and pyrimidine metabolism.

Impact of signal-to-noise ratio and contrast definition on the sensitivity assessment and benchmarking of fluorescence molecular imaging systems.

Standardization of fluorescence molecular imaging (FMI) is critical for ensuring quality control in guiding surgical procedures. To accurately evaluate system performance, two metrics, the signal-to-noise ratio (SNR) and contrast, are widely employed. However, there is currently no consensus on how these metrics can be computed. We aim to examine the impact of SNR and contrast definitions on the performance assessment of FMI systems. We quantified the SNR and contrast of six near-infrared FMI systems by imaging a multi-parametric phantom. Based on approaches commonly used in the literature, we quantified seven SNRs and four contrast values considering different background regions and/or formulas. Then, we calculated benchmarking (BM) scores and respective rank values for each system. We show that the performance assessment of an FMI system changes depending on the background locations and the applied quantification method. For a single system, the different metrics can vary up to (SNR), . (contrast), and . (BM score). The definition of precise guidelines for FMI performance assessment is imperative to ensure successful clinical translation of the technology. Such guidelines can also enable quality control for the already clinically approved indocyanine green-based fluorescence image-guided surgery.

Advancing Pediatric Surgery with Indocyanine Green: Nonhepatobiliary Applications and Outcomes

ABSTRACT Aim: This prospective single-center study aimed to evaluate the nonhepatobiliary applications of indocyanine green fluorescence-guided surgery (ICG FGS) in pediatric patients, assessing its utility as an adjunct for intraoperative imaging. Materials and Methods: Over a 30-month period from January 2021 to July 2023, pediatric patients undergoing various surgical procedures, excluding hepatobiliary cases, were included in the study. ICG (Aurogreen™) was administered intravenously or directly injected in tissue, and fluorescence imaging was conducted using specialized equipment (KARL STORZ GmbH and Co. KG). Patient demographics, diagnoses, surgical procedures, ICG protocols, intraoperative findings, and perioperative outcomes were analyzed. Results: The study included seventeen pediatric cases including Hirschsprung disease, anorectal malformations, undescended testes, varicocele, Mayer-Rokitansky-Kustner-Hauser syndrome, ovarian torsion, chylous ascites, chylothorax, and Wilms’ tumor. ICG aided in the real-time assessment of vascular, intestinal perfusion in Hirschsprung disease, anorectal malformations, delineation of lymphatics from vessels in varicocele, confirmation of preserved vascularity after detorsion of ovary, identification of lymphatics for ligation in chylothorax, and chylous ascites. ICG thus aided in precise dissection and confirming tissue viability without reported adverse events. Conclusion: ICG FGS demonstrates significant potential as a tool for enhancing surgical outcomes in pediatric surgeries including indications beyond hepatobiliary cases. The findings suggest that ICG FGS can improve surgical precision by providing real-time assessment of tissue perfusion, and lymphatic mapping, thereby potentially reducing intraoperative complications. Further research and prospective studies are essential to validate its efficacy and establish standardized protocols, aiming to integrate ICG FGS as a routine adjunct in pediatric surgical practice.

Review of Clinically Assessed Molecular Fluorophores for Intraoperative Image Guided Surgery.

The term "fluorescence" was first proposed nearly two centuries ago, yet its application in clinical medicine has a relatively brief history coming to the fore in the past decade. Nowadays, as fluorescence is gradually expanding into more medical applications, fluorescence image-guided surgery has become the new arena for this technology. It allows surgical teams to real-time visualize target tissues or anatomies intraoperatively to increase the precision of resection or preserve vital structures during open or laparoscopic surgeries. In this review, we introduce the concept of near-infrared fluorescence guided surgery, discuss the recent and ongoing clinical trials of molecular fluorophores (indocyanine green, 5-aminolevulinic acid, methylene blue, IR-dye 800CW, pafolacianine) and their surgical goals, highlight key chemical and medical factors for imaging agent optimization, deliberate challenges and potential advantages, and propose a framework for integrating this technology into routine surgical care in the near future. The notable clinical achievements of these fluorophores over the past decade strongly indicates that the future of fluorescence in surgery is bright with many more patient benefits to come.

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.

Ex Vivo Human Tissue Functions as a Testing Platform for the Evaluation of a Nerve-Specific Fluorophore.

Selecting a nerve-specific lead fluorescent agent for translation in fluorescence-guided surgery is time-consuming and expensive. Preclinical fluorescent agent studies rely primarily on animal models, which are a critical component of preclinical testing, but these models may not predict fluorophore performance in human tissues. The primary aim of this study was to evaluate and compare two preclinical models to test tissue-specific fluorophores based on discarded human tissues. The secondary aim was to use these models to determine the ability of a molecularly targeted fluorophore, LGW16-03, to label ex vivo human nerve tissues. Patients undergoing standard-of-care transtibial or transfemoral amputation were consented and randomized to topical or systemic administration of LGW16-03 following amputation. After probe administration, nerves and background tissues were surgically resected and imaged to determine nerve fluorescence signal-to-background tissue ratio (SBR) and signal-to-noise ratio (SNR) metrics. Analysis of variance (ANOVA) determined statistical differences in metric means between administration cohorts and background tissue groups. Receiver operating characteristic (ROC) curve-derived statistics quantified the discriminatory performance of LGW16-03 fluorescence for labeling nerve tissues. Tissue samples from 18 patients were analyzed. Mean nerve-to-adipose SBR was greater than nerve-to-muscle SBR (p = 0.001), but mean nerve-to-adipose SNR was not statistically different from mean nerve-to-muscle SNR (p = 0.069). Neither SBR nor SNR means were statistically different between fluorophore administration cohorts (p ≥ 0.448). When administration cohorts were combined, nerve-to-adipose SBR was greater than nerve-to-muscle SBR (mean ± standard deviation; 4.2 ± 2.9 vs. 1.8 ± 1.9; p < 0.001), but SNRs for nerve-to-adipose and nerve-to-muscle were not significantly different (5.1 ± 4.0 vs. 3.1 ± 3.4; p = 0.055). ROC curve-derived statistics to quantify LGW16-03 nerve labeling performance varied widely between patients, with sensitivities and specificities ranging from 0.2-99.9% and 0.4-100.0%. Systemic and topical administration of LGW16-03 yielded similar fluorescence labeling of nerve tissues. Both administration approaches provided nerve-specific contrast similar to that observed in preclinical animal models. Fluorescence contrast was generally higher for nerve-to-adipose versus nerve-to-muscle. Ex vivo human tissue models provide safe evaluation of fluorophores in the preclinical phase and can aid in the selection of lead agents prior to first-in-human trials.

Current Practices and Perceptions of Indocyanine Green Fluorescence Guided Liver Surgery: Insights from a Survey of Hepato-Pancreato-Biliary Surgeons in the United Kingdom.

Indocyanine Green (ICG) fluorescence-guided surgery (I-FIGS) is increasingly being used in hepato-pancreatico-biliary (HPB) surgery. However, the true benefit of I-FIGS, the optimum dosing, and the timing of ICG administration still need to be determined. To conduct future research studies in the above areas, it is essential to understand the current I-FIGS practices among surgeons. This survey investigated the practices and perceptions of I-FIGS in liver surgery among HPB surgeons in the United Kingdom (UK). A survey was sent via email and social media to surgeons from all HPB units in the UK. The survey consisted of 18 questions, covering various aspects such as experience levels, volume of operations, approach to liver resections, ICG dosage, timing of administration, application specifics, camera systems used, and willingness to participate in future trials. The survey was sent to 81 HPB surgeons (working in 25 HPB units) across the UK. The response rate was 70% (57/81 surgeons). 56% of the surgeons reported having the infrastructure for I-FIGS at their hospital. The use of I-FIGS varied in duration and patient volume, with 47% of surgeons reporting its use for less than one year and 53% of surgeons reporting using it in fewer than ten patients. Preferences for the dose and timing of ICG administration also varied, reflecting the absence of standardised guidelines. The Storz camera system emerged as the most used imaging system (42% of surgeons), followed by the Stryker (25.8%). None of the surgeons reported any I-FIGS-related side effects. Ninety-six per cent of surgeons expressed interest in participating in future clinical trials in the field of I-FIGS. The survey highlights that I-FIGS in liver surgery is not widely used in the UK. There are also wide variations in the dosing and timing of ICG administration. Large multi-centre studies are needed to focus on dosing, timing of ICG administration, and establishing its actual role in liver surgery.

Temporal dynamics of fluorescence and photoacoustic signals of a Cetuximab-IRDye800 conjugate in EGFR-overexpressing tumors.

Molecular fluorescence-guided surgery has shown promise for tumor margin delineation but is limited by its depth profiling capability. Interestingly, most fluorophores, either clinically approved or in clinical trials, can also be used as photoacoustic contrast agents, yet their use is limited due to the low light fluence permitted for clinical use and the limited sensitivity of current photoacoustic imaging systems. There is therefore an urgent unmet need to establish methods for enhancing contrast in molecular targeted PA imaging which could potentially complement and overcome limitations in molecular fluorescence guided therapies. In this study, we compare the photoacoustic (PA) and fluorescence imaging capabilities of a cetuximab-IRDye800 conjugate in a subcutaneous tumor xenograft model. We demonstrate that while the fluorescence signal increases steadily over time after administration of cetuximab-IRDye800, PA signal peaks early (~2 fold higher at 6-hour as compared to pre-injection controls) and then decreases (~1.3 fold higher at 24-hour as compared to pre-injection controls). This pattern aligns with previous findings using other antibody-conjugated PA contrast agents. Mechanistically, we demonstrate that the formation of H-aggregates upon antibody conjugation enhances PA contrast of the IRDye800. The disruption of these H-aggregates, as the antibody-dye conjugate is degraded post receptor-mediated endocytosis, decreases PA signal intensity. The timeframe of maximum PA signal and decrease thereafter is consistent with the time frame of receptor-mediated endocytosis of cetuximab-IRDye800. Our data suggests that tumor cell surface binding results in peak PA signal while lysosomal localization and degradation results in a significant drop in PA signal. Our study sheds light on the distinct temporal dynamics of PA and fluorescence signals of Cetuximab-IRDye800 conjugate and we propose that optimizing IRDye800 conjugation to antibodies can further enhance PA signal intensity when timed to precisely to capture IRDye800 in an H-aggregate form.

Fluorescence-Guided Surgery Using 5-Aminolevulinic Acid/Protoporphyrin IX in Brain Metastases

BACKGROUND AND OBJECTIVES: The purpose of this systematic review was to provide a comprehensive overview of the available literature on 5-aminolevulinic acid (5-ALA)–induced protoporphyrin IX (PpIX) fluorescence-guided surgery (FGS) for the resection of brain metastases (BMs). METHODS: A comprehensive search of the PubMed database for literature on 5-ALA use in BMs surgery was performed. For inclusion, BMs studies had to have data on the observed intraoperative fluorescence available. Additional data categories included the number of metastatic tumors, 5-ALA dosage and timing, the imaging system (eg, microscope) used, imaging wavelength(s), fluorescence grading (“simple” and “detailed”), fluorescence consistency (heterogeneous vs homogeneous), intracranial tumor location, metastatic primary tumor location, and extent of resection, among others. RESULTS: Twenty-three articles published between 2007 and 2022 met the inclusion criteria. These studies comprised 1709 total patients; 870 metastatic samples were collected from 855 patients with 377 (43.3%) fluorescence-negative and 493 (56.7%) fluorescence-positive samples. The pooled overall prevalence of fluorescence-positive metastatic lesions was 66% (95% CI 55%-75%; I2 = 85%, P &lt; .01). The fluorescence grading was as follows: (a) simple fluorescence (n = 599): 295 (49.3%) fluorescence-negative and 304 (50.8%) fluorescence-positive samples and (b) detailed fluorescence (n = 271): 82 (30.3%) no fluorescence, 107 (39.5%) weak fluorescence, and 82 (30.3%) strong fluorescence. A total of 764 lesions had primary tumor site data available: 702 lesions had fluorescence data with 384 (54.7%) fluorescence-positive samples. CONCLUSION: FGS using 5-ALA/PpIX in BMs demonstrates varying benefits as an adjunct for maximizing the extent of resection. Thus, preoperative knowledge of the primary tumors' origin may inform surgeons regarding the potential utility of 5-ALA/PpIX for FGS management of BMs.

Enhancing Glioblastoma Resection with NIR Fluorescence Imaging: A Systematic Review.

Glioblastoma (GB) is among the most aggressive and difficult-to-treat brain tumors, with a median survival of only 12-15 months despite maximal treatments, including surgery, radiotherapy, and chemotherapy. Extensive surgical resection improves survival in glioblastoma patients; however, achieving complete resection is often hindered by limitations in neurosurgical guidance technologies for accurate tumor margin detection. Recent advancements in fluorescence-guided surgery (FGS) and imaging techniques have significantly enhanced the precision and extent of glioblastoma resections. This study evaluates the impact of NIR fluorescence imaging on tumor visualization, surgical precision, cost-effectiveness, and patient survival. A systematic review of PubMed, Scopus, Google Scholar, and Embase was conducted to identify studies on the role of NIR fluorescence in glioblastoma surgery. A total of 135 studies were included, comprising 10 reviews, three clinical studies, 10 randomized controlled trials (RCTs), 10 preclinical studies, and four case reports, all focused on NIR fluorescence imaging in glioblastoma surgery. The findings indicate that NIR fluorescence imaging significantly improves tumor visualization, resulting in an 18-22% increase in gross total resection (GTR) rates in clinical studies. NIR fluorescence provides continuous real-time feedback, minimizing repeat imaging, reducing operational costs, and increasing GTR. These improvements contribute to better patient outcomes, including extended progression-free survival, improved overall survival, and reduced postoperative neurological deficits. This review underscores the potential of NIR imaging to establish a new standard for intraoperative glioblastoma management.

ICG-guided sentinel lymph node biopsy in melanoma is as effective as blue dye: A retrospective analysis

IntroductionSentinel lymph node biopsy (SLNB) is a key procedure in the staging and management of melanoma. Traditionally, it is performed using a dual-mapping technique combining a radioactive isotope (RI) and blue dye (BD). Fluorescence-guided surgery with indocyanine green (ICG) has emerged as an alternative tracer, offering potential advantages in real-time visualization and operative efficiency. This study compares the efficacy of RI + ICG with RI + BD in SLNB for melanoma. MethodsWe conducted a retrospective cohort study at a single center, including 311 patients who underwent SLNB for melanoma. Patients were divided into two groups: RI + BD (n = 227, January 2010–August 2022) and RI + ICG (n = 84, August 2022–February 2024). SLN detection rates, positive SLN rates, operative times, and postoperative complications were compared between the two groups. ResultsBoth groups were clinically and pathologically comparable. SLN detection rates were 100 % in the RI + BD group and 98.8 % in the RI + ICG group (p = 0.1). The median number of lymph nodes resected was lower in the RI + ICG group as compared to the RI + BD group (p = 0.047). While positive SLN rates were higher in the RI + ICG group (9.5 % vs. 6.2 %), this difference was not statistically significant (p = 0.3). ICG alone could not identify all the positive SLN. Postoperative complications, including seroma, did not differ significantly between groups. ConclusionsICG-guided SLNB is comparable to BD-guided SLNB in terms of detection rate and SLN positivity, although it can not be used alone to identify all positive SLNBs. ICG-based fluorescence imaging is a promising technique that may enhance surgical efficiency in melanoma management.

Systematic comparison of fluorescence imaging in the near-infrared and shortwave-infrared spectral range using clinical tumor samples containing cetuximab-IRDye800CW.

Shortwave-infrared (SWIR) imaging is reported to yield better contrast in fluorescence-guided surgery than near-infrared (NIR) imaging, due to a reduction in scattering. This benefit of SWIR was shown in animal studies, however not yet in clinical studies with patient samples. We investigate the potential benefit of SWIR to NIR imaging in clinical samples containing cetuximab-IRDye800CW in fluorescence-guided surgery. The potential of the epidermal growth factor-targeted NIR dye cetuximab-IRDye800CW in the shortwave range was examined by recording the absorption and emission spectrum. An ex vivo comparison of NIR and SWIR images using clinical tumor samples of patients with penile squamous cell carcinoma (PSCC) and head and neck squamous cell carcinoma (HNSCC) containing cetuximab-IRDye800CW was performed. The comparison was based on the tumor-to-background ratio and an adapted contrast-to-noise ratio (aCNR) using the standard of care pathology tissue assessment as the golden standard. Based on the emission spectrum, cetuximab-IRDye800CW can be detected in the SWIR range. In clinical PSCC samples, overall SWIR imaging was found to perform similarly to NIR imaging (NIR imaging is better than SWIR in the 2/7 criteria examined, and SWIR is better than NIR in the 3/7 criteria). However, when inspecting HNSCC data, NIR is better than SWIR in nearly all (5/7) examined criteria. This difference seems to originate from background autofluorescence overwhelming the off-peak SWIR fluorescence signal in HNSCC tissue. SWIR imaging using the targeted tracer cetuximab-IRDye800CW currently does not provide additional benefit over NIR imaging in ex vivo clinical samples. Background fluorescence in the SWIR region, resulting in a higher background signal, limits SWIR imaging in HNSCC samples. However, SWIR shows potential in increasing the contrast of tumor borders in PSCC samples, as shown by a higher aCNR over a line.

Selecting Targets for Molecular Imaging of Gastric Cancer: An Immunohistochemical Evaluation.

Tumor-targeted positron emission tomography (PET) and fluorescence-guided surgery (FGS) could address current challenges in pre- and intraoperative imaging of gastric cancer. Adequate selection of molecular imaging targets remains crucial for successful tumor visualization. This study evaluated the potential of integrin αvβ6, carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), epidermal growth factor receptor (EGFR), epithelial cell adhesion molecule (EpCAM) and human epidermal growth factor receptor-2 (HER2) for molecular imaging of primary gastric cancer, as well as lymph node and distant metastases. Expression of αvβ6, CEACAM5, EGFR, EpCAM and HER2 was determined using immunohistochemistry in human tissue specimens of primary gastric adenocarcinoma, healthy surrounding stomach, esophageal and duodenal tissue, tumor-positive and tumor-negative lymph nodes, and distant metastases, followed by quantification using the total immunostaining score (TIS). Positive biomarker expression in primary gastric tumors was observed in 86% for αvβ6, 72% for CEACAM5, 77% for EGFR, 93% for EpCAM and 71% for HER2. Tumor expression of CEACAM5, EGFR and EpCAM was higher compared to healthy stomach tissue expression, while this was not the case for αvβ6 and HER2. Tumor-positive lymph nodes could be distinguished from tumor-negative lymph nodes, with accuracy ranging from 82 to 93% between biomarkers. CEACAM5, EGFR and EpCAM were abundantly expressed on distant metastases, with expression in 88-95% of tissue specimens. Our findings show that CEACAM5, EGFR and EpCAM are promising targets for molecular imaging of primary gastric cancer, as well as visualization of both lymph node and distant metastases. Further clinical evaluation of PET and FGS tracers targeting these antigens is warranted.

Near-infrared fluorescent molecular probes with cetuximab in the in vivo fluorescence imaging for epithelial ovarian cancer

BackgroundNear-infrared fluorescence (NIRF) imaging is an excellent choice for image-guided surgery due to its simple operation and non-invasiveness. Developing tumor-specific fluorescent molecular probes is key to fluorescence imaging-guided surgery. EGFR (epidermal growth factor receptor) is closely related to the proliferation and growth of tumor cells and is highly expressed in epithelial ovarian cancer (EOC). The study aims to construct a NIR fluorescent molecular probe using cetuximab (an EGFR monoclonal antibody) and investigate its feasibility for targeting EOC in vivo through fluorescence imaging.MethodsWe determined the expression of EGFR in EOC. NIR fluorescent molecular probe with cetuximab (cetuximab-Cy7) was chemically engineered and identified. The subcutaneous xenografted tumor model of EOC was induced using SKOV3-Luc cell line with positive expression of EGFR. Cetuximab-Cy7 was used for in vivo fluorescence imaging, and phosphate-buffered saline, free Cy7 dye and mouse isotype immunoglobulin G-Cy7 were used as controls. NIRF imaging system was performed to study the distribution and targeting of the probes. Tumors were imaged in situ and ex vivo, and fluorescent intensity was quantified. Resected specimens were analyzed to confirm diagnosis, and immunohistochemical (IHC) staining was used to identify EGFR expression.ResultsEGFR expression was increased in EOC tissues than fallopian tube tissues. The high expression of EGFR was significantly correlated with well-differentiation, residual lesions ≤ 1 cm, no recurrence and increased survival. NIRF imaging showed that the cetuximab-Cy7 enabled detection of tumor lesions in EOC-bearing mice with the optimal dose of 30 µg. The suitable imaging time window may be 24–96 h post-injection. Ex vivo fluorescence imaging indicated that fluorescent signal was mainly detected in the tumor and the lung. IHC results confirmed that xenografts were EGFR positive.ConclusionCetuximab-Cy7 can specifically target the tumors of EOC xenografted nude mice. This research lays the foundation for future studies on EOC surgery navigation.

Hyperspectral imaging in neurosurgery: a review of systems, computational methods, and clinical applications.

Accurate identification between pathologic (e.g., tumors) and healthy brain tissue is a critical need in neurosurgery. However, conventional surgical adjuncts have significant limitations toward achieving this goal (e.g., image guidance based on pre-operative imaging becomes inaccurate up to 3cm as surgery proceeds). Hyperspectral imaging (HSI) has emerged as a potential powerful surgical adjunct to enable surgeons to accurately distinguish pathologic from normal tissues. We review HSI techniques in neurosurgery; categorize, explain, and summarize their technical and clinical details; and present some promising directions for future work. We performed a literature search on HSI methods in neurosurgery focusing on their hardware and implementation details; classification, estimation, and band selection methods; publicly available labeled and unlabeled data; image processing and augmented reality visualization systems; and clinical study conclusions. We present a detailed review of HSI results in neurosurgery with a discussion of over 25 imaging systems, 45 clinical studies, and 60 computational methods. We first provide a short overview of HSI and the main branches of neurosurgery. Then, we describe in detail the imaging systems, computational methods, and clinical results for HSI using reflectance or fluorescence. Clinical implementations of HSI yield promising results in estimating perfusion and mapping brain function, classifying tumors and healthy tissues (e.g., in fluorescence-guided tumor surgery, detecting infiltrating margins not visible with conventional systems), and detecting epileptogenic regions. Finally, we discuss the advantages and disadvantages of HSI approaches and interesting research directions as a means to encourage future development. We describe a number of HSI applications across every major branch of neurosurgery. We believe these results demonstrate the potential of HSI as a powerful neurosurgical adjunct as more work continues to enable rapid acquisition with smaller footprints, greater spectral and spatial resolutions, and improved detection.

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

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. 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. 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. 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.

SURG-18. INNOVATIVE DRUG-DEVICE COMBINATION FOR THE PHOTODYNAMIC TREATMENT OF PRIMARY GLIOBLASTOMA (GBM) PATIENTS

Abstract Despite advances in neurosurgical technology and techniques, the survival rate of GBM patients has remained relatively unchanged. The main treatments for GBM are associated with difficulties resulting from incomplete tumor resection and recurrence. In such situations, Photodynamic Therapy (PDT) is increasingly popular as an advanced therapeutic strategy, characterized by fewer side effects, minimal toxicity, and more controlled treatment. 5-aminolevulinic acid hydrochloride, (5-ALA HCl) has been used for years as a photosensitizing drug for the intraoperative visualization of GBM tumor tissue, enabling a more complete tumor resection. We demonstrated that, after such fluorescence-guided surgery, a laser light of specific 635 nm wavelength can additionally induce specific tumor cell death via the production of reactive oxygen species. This 5-ALA HCl–based PDT provides an antitumor effect within the tumor resection margins where recurrences occur in almost all patients. After performing pilot studies in over 20 patients with primary GBM, leading to positive safety and survival signals, we designed a new drug-device combination for this specific PDT procedure. It consists of Pentalafen ®, 5-ALA HCl administered orally to the patient before surgery, combined to Heliance®, a balloon device, inflated intraoperatively into the resection cavity, and connected to a controller (laser system) via an optical fiber to produce the light that illuminates the resection margins. A dedicated algorithm enables the duration of the illumination to be automatically computed from the tumor volume. This procedure adds an average of 30 minutes to the neurosurgery and can thus be fully integrated into the standard of care for primary GBM. This new drug-device combination is currently evaluated in a US phase 1 trial (NCT05736406) evaluating the feasibility of different light regimen treatments with the aim of delaying GBM recurrence and improving overall survival. If data is confirmed, it could be applicable to other CNS and solid tumors.

INNV-05. DEVELOPMENT OF A LABEL-FREE PLASMONIC OPTICAL BIOSENSOR FOR INTRAOPERATIVE DETECTION OF TUMOR TISSUE IN GLIOBLASTOMA

Abstract Safe maximal resection of patients with glioblastoma remains a surgical challenge due to the invasive nature of the tumor and the difficulty in distinguishing tumor margins during resection. Several tools are currently used for this purpose, such as, confocal laser endomicroscopy and fluorescence-guided surgery. In this context, biosensors based on plasmonic technology using the extraordinary optical transmission (EOT) phenomenon can help to distinguish between tumor and surrounding tissue based on their optical properties. We developed a biosensor utilizing EOT through a nanostructured gold matrix with 220 nm diameter holes and conducted a prospective study in 35 GBM patients. Paired samples of tumor and peritumoral tissue were collected during surgery. Each sample’s optical imprint was analyzed, revealing significant differences in refractive indices (RI). Tumor tissue showed higher RI values (1.350, IQR 1.344–1.363) compared to peritumoral tissue (1.341, IQR 1.339–1.349) with a p-value of 0.0047. The receiver operating characteristic (ROC) curve indicated the biosensor’s ability to differentiate the tissues (AUC = 0.8779, p &amp;lt; 0.0001). An optimal RI cut-off point of 0.003 was determined, with the biosensor achieving 81% sensitivity and 80% specificity. Our results indicate that this plasmonic technology-based biosensor could have a significant impact on the surgical treatment of glioblastoma by providing a label-free tool for tumor margin discrimination and improving the accuracy of glioblastoma surgery. Future research will focus on optimizing the nanoarchitecture of the biosensor to further improve its sensitivity and specificity, as well as exploring its applicability to other cancer types by analyzing the biomarkers responsible for the different RIs of the footprints.

Fluorescence-guided tumor visualization of colorectal cancer using tumor-initiating probe yellow in preclinical models

Fluorescence-guided surgery has emerged as an innovative technique with promising applications in the treatment of various tumors, including colon cancer. Tumor-initiating probe yellow (TiY) has been discovered for identifying tumorigenic cells by unbiased phenotypic screening with thousands of diversity-oriented fluorescence library (DOFL) compounds in a patient-derived lung cancer cell model. This study demonstrated the clinical feasibility of TiY for tumor-specific fluorescence imaging in the tissues of patients with colorectal cancer (CRC). To evaluate the efficacy of TiY in tumor imaging, surgical specimens were obtained, consisting of 36 tissues from 18 patients with CRC, for ex vivo molecular fluorescence imaging, histology, and immunohistochemistry. Orthotopic and chemically induced CRC mice models were administered TiY topically, and distinct tumor lesions were observed in 10 min by real-time fluorescence colonoscopy and ex vivo imaging. In a hepatic metastasis mouse model using splenic injection, TiY accumulation was detected in metastatic liver lesions through fluorescence imaging. Correlation analysis between TiY intensity and protein expression, assessed via immunohistochemistry and Western blotting, revealed a positive correlation between TiY and vimentin and Zeb1, which are known as epithelial–mesenchymal transition (EMT) markers of cancers. A comparative analysis of TiY with other FDA-approved fluorescence probes such as ICG revealed greater quantitative differences in TiY fluorescence intensity between tumor and normal tissues than those observed with ICG. Altogether, these results demonstrated that TiY has a strong potential for visualizing CRC by fluorescence imaging in various preclinical models, which can be further translated for clinical use such as fluorescence-guided surgery. Furthermore, our data indicate that TiY is preferentially uptaken by cells with EMT induction and progression, and overexpressing vimentin and Zeb1 in patients with CRC.