Oncologic Procedures Amenable to Fluorescence-guided Surgery

A Phase 2 Multicenter Clinical Trial of Intraoperative Molecular Imaging of Lung Cancer with a pH-Activatable Nanoprobe

PURPOSE

Intraoperative molecular imaging (IMI) uses tumor-targeted optical contrast agents to improve identification and clearance of cancer. Recently, a probe has been developed that only fluoresces when activated in an acidic pH, which is common to many malignancies. We report the first multicenter Phase 2 trial of a pH-activatable nanoprobe (pegsitacianine, ONM-100) for IMI of lung cancer.

METHODS

Patients with suspected or biopsy-confirmed lung cancer scheduled for sublobar resection were administered a single intravenous infusion of pegsitacianine (1 mg/kg) one to three days prior to surgery. Intraoperatively, the patients underwent a white light thoracoscopic evaluation, and then were imaged with an NIR thoracoscope to detect tumor fluorescence. The primary study endpoint was the proportion of patients with a clinically significant event (CSE) which was defined as an intraoperative discovery during IMI that led to a change in the surgical procedure. Possible CSEs included (i) localizing the index lung nodule that could not be located by white light, (ii) identifying a synchronous malignant lesion, or (iii) recognizing a close surgical margin (< = 10 mm). Secondary endpoints were sensitivity, specificity, NPV, and PPV of pegsitacianine in detecting tumor-containing tissue. The safety evaluation was based on adverse event reporting, clinical laboratory parameters, and physical examinations.

RESULTS

Twenty patients were confirmed as eligible and administered pegsitacianine. Most of the patients were female (n = 12 [60%]), middle-aged (mean age 63.4 years), and former smokers (n = 13 [65%], 28.6 mean pack years). Mean lesion size was 1.9 cm, and most lesions (n = 17 [85%]) were malignant. The most common histologic subtype was adenocarcinoma (n = 9). By utilizing IMI with pegsitacianine, one patient had a CSE in the detection of a close margin and another had localization of a tumor not detectable by traditional surgical means. Six of 19 (31.6%) malignant lesions fluoresced with mean tumor-to-background ratio (TBR) of 3.00, as compared to TBR of 1.20 for benign lesions (n = 3). Sensitivity and specificity of pegsitacianine-based IMI for detecting malignant tissue was 31.6% and 33.3%, respectively. Positive predictive value (PPV) and negative predictive value (NPV) of pegsitacianine-based IMI was 75% and 7.1%, respectively. Pegsitacianine-based imaging was not effective in differentiating benign and malignant lymph nodes. From a safety perspective, no drug-related serious adverse events occurred. Four patients experienced mild pegsitacianine-related infusion reactions which required discontinuing the study drug with complete resolution of symptoms.

CONCLUSIONS

Pegsitacianine-based IMI, though well tolerated from a safety perspective, does not consistently label lung tumors during resection and does not provide significant clinical benefit over existing standards of surgical care. The biology of lung tumors may not be as acidic as other solid tumors in the body thereby not activating the probe as predicted.

Polystyrene-Based Matrix to Enhance the Fluorescence of Aggregation-Induced Emission Luminogen for Fluorescence-Guided Surgery

Achieving ultrabright fluorogens is a key issue for fluorescence-guided surgery (FGS). Fluorogens with aggregation-induced emission (AIEgens) are potential agents for FGS on the benefit of the bright fluorescence in physiological conditions. Herein, the fluorescence brightness of AIEgen is further improved by preparing the nanoparticle using a polystyrene-based matrix and utilizing it for tumor FGS with a high signal-to-background ratio. After encapsulating AIEgen into polystyrene-poly (ethylene glycol) (PS-PEG), the fluorescence intensity of the prepared AIE@PS-PEG nanoparticles is multiple times that of nanoparticles in 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-poly (ethylene glycol) (DSPE-PEG), a commonly used polymer matrix for nanoparticle preparation. Molecular dynamics simulations suggest that higher free energy is required for the outer rings of AIEgen to rotate in polystyrene than in the DSPE, indicating that the benzene rings in polystyrene can restrict the intramolecular motions of AIEgen better than the alkyl chain in DSPE-PEG. Fluorescence correlation microscopy detections suggest that the triplet excited state of AIEgens is less in PS-PEG than in DSPE-PEG. The restricted intramolecular motions and suppressed triplet excited state result in ultrabright AIE@PS-PEG nanoparticles, which are more conducive to illuminating tumor tissues in the intestine for FGS. The illumination of metastatic tumors in lungs by AIE@PS-PEG nanoparticles is also tried.

Comparative Study of Indocyanine Green Fluorescence Imaging in Lung Cancer with Near-Infrared-I/II Windows

BACKGROUND

We compare the application of intravenous indocyanine green (ICG) fluorescence imaging in lung cancer with near-infrared-I (NIR-I) and near-infrared-II (NIR-II) windows.

METHODS

From March to December 2022, we enrolled patients who received an intravenous injection of ICG (5 mg/kg) 1 day before the planned lung cancer surgery. The lung cancer nodules were imaged by NIR-I/II fluorescence imaging systems, and the tumor-to-normal-tissue ratio (TNR) was calculated. In addition, the fluorescence intensity and signal-to-background ratio (SBR) of capillary glass tubes containing ICG covered with different thicknesses of lung tissue were measured by NIR-I/II fluorescence imaging systems.

RESULTS

In this study, 102 patients were enrolled, and the mean age was 59.9 ± 9.2 years. A total of 96 (94.1%) and 98 (96.1%) lung nodules were successfully imaged with NIR-I and NIR-II fluorescence, and the TNR of NIR-II was significantly higher than that of NIR-I (3.9 ± 1.3 versus 2.4 ± 0.6, P < 0.001). In multiple linear regression, solid nodules (P < 0.001) and squamous cell carcinoma (P < 0.001) were independent predictors of a higher TNR of NIR-I/II. When capillary glass tubes were covered with lung tissue whose thickness was more than 2 mm, the fluorescence intensity and the SBR of NIR-II were significantly higher than those of NIR-I.

CONCLUSIONS

We verified the feasibility of NIR-II fluorescence imaging in intravenous ICG lung cancer imaging for the first time. NIR-II fluorescence can improve the TNR and penetration depth of lung cancer with promising clinical prospects.

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.

AAPM Task Group Report 311: Guidance for performance evaluation of fluorescence-guided surgery systems

The last decade has seen a large growth in fluorescence-guided surgery (FGS) imaging and interventions. With the increasing number of clinical specialties implementing FGS, the range of systems with radically different physical designs, image processing approaches, and performance requirements is expanding. This variety of systems makes it nearly impossible to specify uniform performance goals, yet at the same time, utilization of different devices in new clinical procedures and trials indicates some need for common knowledge bases and a quality assessment paradigm to ensure that effective translation and use occurs. It is feasible to identify key fundamental image quality characteristics and corresponding objective test methods that should be determined such that there are consistent conventions across a variety of FGS devices. This report outlines test methods, tissue simulating phantoms and suggested guidelines, as well as personnel needs and professional knowledge bases that can be established. This report frames the issues with guidance and feedback from related societies and agencies having vested interest in the outcome, coming from an independent scientific group formed from academics and international federal agencies for the establishment of these professional guidelines.

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.

Nanoparticles drug delivery for 5-aminolevulinic acid (5-ALA) in photodynamic therapy (PDT) for multiple cancer treatment: a critical review on biosynthesis, detection, and therapeutic applications

Photodynamic therapy (PDT) is a promising cancer treatment that kills cancer cells selectively by stimulating reactive oxygen species generation with photosensitizers exposed to specific light wavelengths. 5-aminolevulinic acid (5-ALA) is a widely used photosensitizer. However, its limited tumour penetration and targeting reduce its therapeutic efficacy. Scholars have investigated nano-delivery techniques to improve 5-ALA administration and efficacy in PDT. This review summarises recent advances in biological host biosynthetic pathways and regulatory mechanisms for 5-ALA production. The review also highlights the potential therapeutic efficacy of various 5-ALA nano-delivery modalities, such as nanoparticles, liposomes, and gels, in treating various cancers. Although promising, 5-ALA nano-delivery methods face challenges that could impair targeting and efficacy. To determine their safety and biocompatibility, extensive preclinical and clinical studies are required. This study highlights the potential of 5-ALA-NDSs to improve PDT for cancer treatment, as well as the need for additional research to overcome barriers and improve medical outcomes.

Near-Infrared Fluorescence Imaging in Preclinical Models of Glioblastoma

Cancer is a public health problem requiring ongoing research to improve current treatments and discover novel therapies. More accurate imaging would facilitate such research. Near-infrared fluorescence has been developed as a non-invasive imaging technique capable of visualizing and measuring biological processes at the molecular level in living subjects. In this work, we evaluate the tumor activity in two preclinical glioblastoma models by using fluorochrome (IRDye 800CW) coupled to different molecules: tripeptide Arg-Gly-Asp (RGD), 2-amino-2-deoxy-D-glucose (2-DG), and polyethylene glycol (PEG). These molecules interact with pathological conditions of tumors, including their overexpression of αvβ3 integrins (RGD), elevated glucose uptake (2-DG), and enhanced permeability and retention effect (PEG). IRDye 800CW RGD gave the best in vivo fluorescence signal from the tumor area, which contrasted well with the low fluorescence intensity of healthy tissue. In the ex vivo imaging (dissected tumor), the accumulation of IRDye 800CW RGD could be appreciated at the tumor site. Glioblastoma tumors were presently detected with specificity and sensitivity by utilizing IRDye 800CW RGD, a near-infrared fluorophore combined with a marker of αvβ3 integrin expression. Further research is needed on its capacity to monitor tumor growth in glioblastoma after chemotherapy.

Indocyanine Green (ICG) and Colorectal Surgery: A Literature Review on Qualitative and Quantitative Methods of Usage

Background: Due to its many benefits, indocyanine green (ICG) has gained progressive popularity in operating rooms (ORs) globally. This literature review examines its qualitative and quantitative usage in surgical treatment. Method: Relevant terms were searched in five international databases (1. Pubmed, 2. Sciencedirect, 3. Scopus, 4. Oxfordjournals, 5. Reaxys) for a comprehensive literature review. The main benefits of using ICG in colorectal surgery are: intraoperative fluorescence angiography; fluorescence-guided lymph node involvement detection and the sentinel technique; the fluorescent emphasis of a minute liver tumour, counting just 200 tumour cells; facilitation of fistula diagnosis; and tumour tattooing. This methodology can also be used with quantitative characteristics such as maximum intensity, relative maximum intensity, and in-flow parameters such as time-to-peak, slope, and t1/2max. This article concludes that fluorescence surgery with ICG and near-infrared (NIR) light is a relatively new technology that improves anatomical and functional information, allowing more comprehensive and safer tumour removal and the preservation of important structures.

Advances in optical molecular imaging for neural visualization

Iatrogenic nerve injury is a significant complication in surgery, which can negatively impact patients' quality of life. Currently, the main clinical neuroimaging methods, such as computed tomography, magnetic resonance imaging, and high-resolution ultrasonography, do not offer precise real-time positioning images for doctors during surgery. The clinical application of optical molecular imaging technology has led to the emergence of new concepts such as optical molecular imaging surgery, targeted surgery, and molecular-guided surgery. These advancements have made it possible to directly visualize surgical target areas, thereby providing a novel method for real-time identification of nerves during surgery planning. Unlike traditional white light imaging, optical molecular imaging technology enables precise positioning and identifies the cation of intraoperative nerves through the presentation of color images. Although a large number of experiments and data support its development, there are few reports on its actual clinical application. This paper summarizes the research results of optical molecular imaging technology and its ability to realize neural visualization. Additionally, it discusses the challenges neural visualization recognition faces and future development opportunities.

Small-molecule probes from bench to bedside: advancing molecular analysis of drug-target interactions toward precision medicine

Over the past decade, remarkable advances have been witnessed in the development of small-molecule probes. These molecular tools have been widely applied for interrogating proteins, pathways and drug-target interactions in preclinical research. While novel structures and designs are commonly explored in probe development, the clinical translation of small-molecule probes remains limited, primarily due to safety and regulatory considerations. Recent synergistic developments - interfacing novel chemical probes with complementary analytical technologies - have introduced and expedited diverse biomedical opportunities to molecularly characterize targeted drug interactions directly in the human body or through accessible clinical specimens (e.g., blood and ascites fluid). These integrated developments thus offer unprecedented opportunities for drug development, disease diagnostics and treatment monitoring. In this review, we discuss recent advances in the structure and design of small-molecule probes with novel functionalities and the integrated development with imaging, proteomics and other emerging technologies. We further highlight recent applications of integrated small-molecule technologies for the molecular analysis of drug-target interactions, including translational applications and emerging opportunities for whole-body imaging, tissue-based measurement and blood-based analysis.

Buccal mucosal application of dissolvable microneedle patch containing photosensitizer provides effective localized delivery and phototherapy against oral carcinoma

The effectiveness of phototherapy using photosensitizers is limited by the challenges in their delivery at the site of irradiation. Here, we demonstrate the localized application of a photosensitizer-loaded microneedle patch for effective photodynamic and photothermal therapy in oral carcinoma. Indocyanine green (ICG) was studied as a photosensitizer for its effect on oral carcinoma, FaDu cells. Different parameters including concentration, near-infrared (NIR) laser irradiation intensity and irradiation time were optimized while measuring temperature increase and reactive oxygen species (ROS) generation in FaDu cells. A dissolvable microneedle (DMN) patch made of sodium carboxymethyl cellulose and sodium alginate was fabricated by the micromolding technique. DMN showed sufficient mechanical strength for insertion in the excised porcine buccal mucosa. DMN dissolved within 30 s in phosphate buffer and 30 min in the excised buccal mucosa. Confocal microscopy studies revealed DMN penetration up to a depth of 300 µm within the buccal mucosa. ICG-DMN applied on the back of the rat was found to be localized at the application site before and after irradiation using an 808 nm NIR laser. ICG-DMN was applied on the FaDu xenografted tumor model in athymic nude mice. The localized temperature increase and ROS generation significantly (P<0.05) decreased the tumor volume after ICG-DMN application compared with the control group. In conclusion, DMN can be developed for the localized administration of photosensitizers for phototherapy in oral carcinoma.

A Lysosome-Targeted Near-Infrared Fluorescent Probe with Excellent Water Solubility for Surgery Navigation in Breast Cancer

To get a tumor-targeted contrast agent for imaging guide resection of tumors, we designed a novel fluorescent probe based on the heptamethine cyanine core, Cy7-MO, which has excellent water solubility and near-infrared photophysical and lysosomal targeting properties. The chemical structure of Cy7-MO was characterized by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. The toxicity of Cy7-MO was evaluated by cell counting kit-8. Then, a cellular-level study was conducted to evaluate the suborganelle localization in 4T1-Luc1 cells, and it was also used for surgical navigation in orthotopic breast tumor resection in vivo. The results showed that Cy7-MO was well targeted to lysosomes. Importantly, the Cy7-MO probe was found to be well tolerable and exhibited excellent biocompatibility. Moreover, the orthotopic breast tumor margin was clearly visualized through fluorescence guiding of Cy7-MO. Finally, the correct tumor tissues were completely removed, and a negative margin was obtained successfully, which demonstrated an enhanced precision of surgery.

NIR-II Aza-BODIPY Dyes Bioconjugated to Monoclonal Antibody Trastuzumab for Selective Imaging of HER2-Positive Ovarian Cancer

Using fluorescence-guided surgery (FGS) to cytoreductive surgery helps achieving complete resection of microscopic ovarian tumors. The use of visible and NIR-I fluorophores has led to beneficial results in clinical trials; however, involving NIR-II dyes seems to outperform those benefits due to the deeper tissue imaging and higher signal/noise ratio attained within the NIR-II optical window. In this context, we developed NIR-II emitting dyes targeting human epidermal growth factor receptor 2 (HER2)-positive ovarian tumors by coupling water-soluble NIR-II aza-BODIPY dyes to the FDA-approved anti-HER2 antibody, namely, trastuzumab. These bioconjugated NIR-II-emitting dyes displayed a prolonged stability in serum and a maintained affinity toward HER2 in vitro. We obtained selective targeting of HER2 positive tumors (SKOV-3) in vivo, with a favorable tumor accumulation. We demonstrated the fluorescence properties and the specific HER2 binding of the bioconjugated dyes in vivo and thus their potential for NIR-II FGS in the cancer setting.

Fibronectin-targeting and metalloproteinase-activatable smart imaging probe for fluorescence imaging and image-guided surgery of breast cancer

Residual lesions in the tumor bed have been a challenge for conventional white-light breast-conserving surgery. Meanwhile, lung micro-metastasis also requires improved detection methods. Intraoperative accurate identification and elimination of microscopic cancer can improve surgery prognosis. In this study, a smart fibronectin-targeting and metalloproteinase-activatable imaging probe CREKA-GK8-QC is developed. CREKA-GK8-QC possesses an average diameter of 21.7 ± 2.5 nm, excellent MMP-9 protein responsiveness and no obvious cytotoxicity. In vivo experiments demonstrate that NIR-I fluorescence imaging of CREKA-GK8-QC precisely detects orthotopic breast cancer and micro-metastatic lesions (nearly 1 mm) of lungs with excellent imaging contrast ratio and spatial resolution. More notably, fluorescence image-guided surgery facilitates complete resection and avoids residual lesions in the tumor bed, improving survival outcomes. We envision that our newly developed imaging probe shows superior capacity for specific and sensitive targeted imaging, as well as providing guidance for accurate surgical resection of breast cancer.

NIRDye 812: A molecular platform tailored for multimodal bioimaging applications of targeted fluorescence- and photoacoustic-guided surgery

The primary treatment for malignant tumors remains to be surgical removal of the diseased tissue. The presence or absence of residual diseased tissue at the tumor margin is the strongest predictor of postoperative prognosis and recurrence. Accordingly, reliance on the ability of surgeons to visually distinguish diseased tissue from healthy tissue unambiguously in real time is crucial. Near infrared-I (NIRI) fluorescence-emitting targeting biomolecular constructs such as anticancer antibody-fluorophore conjugates, namely cetuximab-IRDye® 800CW (CTB-IRDye® 800CW), are FDA-approved for clinical trial usage in the fluorescence-guided resection of diseased tissue due to affording improved direct visualization of tumor tissue when compared to the use of either the unaided eye under standard white light illumination (WLI) surgical techniques or non-targeting fluorophores. Unfortunately, though helpful, CTB-IRDye® 800CW affords limited (i) identification of diseased tissue and (ii) tumor margin delineation, because the immunoconjugate generates suboptimal tumor-to-background ratios (TBRs) as a result of its spectral/photophysical profiles poorly aligning with the fixed optical windows of pre-/clinical setups. As such, CTB-IRDye® 800CW is more prone to affording incomplete resection compared to if TBRs were higher due to otherwise. To aid in accurately identifying deep-seated diseased tissue, photoacoustic (PA) tomography has been implemented alongside CTB-IRDye® 800CW to achieve PA signals that could result in higher TBRs. However, in clinical trial practice, using IRDye® 800CW for PA imaging also yields subpar TBRs due to it affording low PA signals. To overcome such limitations, we developed NIRDye 812, a structurally-modified topological equivalent of IRDye® 800CW, to confer it the capability to yield both higher TBRs and superior PA signal than that of the equivalent CTB-conjugate and fluorophore IRDye® 800CW itself, respectively. To do so, we substituted the oxygen atom at its meso-position with a sulfur atom. CTB-NIRDye 812 demonstrated a red-shifted absorption wavelength at 796 nm and a peak NIR-I fluorescence emission wavelength at 820 nm, which better dovetails with the fixed windows of preinstalled fixed emission filters within commercial pre-/clinical NIR-I fluorescence imaging instruments. Overall, CTB-NIRDye 812 provided a ∼ 2-fold increase in TBRs compared to those of CTB-IRDye® 800CW in vivo. Also, NIRDye 812 displayed an ∼60% higher PA signal than that of IRDye® 800CW. Collectively, we achieved our goal of improving upon the spectral/photophysical and PA properties of IRDye® 800CW via introducing a subtle modification to its electronic core such that its CTB immunoconjugate could potentially allow for fast track or breakthrough designation by the FDA due to its near-identical structure displaying considerably improved efficacy.

Fluorescence guidance improves the accuracy of radiological imaging-guided surgical navigation

BACKGROUND

Imaging-based navigation technologies require static referencing between the target anatomy and the optical sensors. Imaging-based navigation is therefore well suited to operations involving bony anatomy; however, these technologies have not translated to soft-tissue surgery. We sought to determine if fluorescence imaging complement conventional, radiological imaging-based navigation to guide the dissection of soft-tissue phantom tumors.

METHODS

Using a human tissue-simulating model, we created tumor phantoms with physiologically accurate optical density and contrast concentrations. Phantoms were dissected using all possible combinations of computed tomography (CT), magnetic resonance, and fluorescence imaging; controls were included. The data were margin accuracy, margin status, tumor spatial alignment, and dissection duration.

RESULTS

Margin accuracy was higher for combined navigation modalities compared to individual navigation modalities, and accuracy was highest with combined CT and fluorescence navigation (p = 0.045). Margin status improved with combined CT and fluorescence imaging.

CONCLUSIONS

At present, imaging-based navigation has limited application in guiding soft-tissue tumor operations due to its inability to compensate for positional changes during surgery. This study indicates that fluorescence guidance enhances the accuracy of imaging-based navigation and may be best viewed as a synergistic technology, rather than a competing one.

Defining the relevance of surgical margins. Part two: Strategies to improve prediction of recurrence risk

Due to the complex nature of tumour biology and the integration between host tissues and molecular processes of the tumour cells, a continued reliance on the status of the microscopic cellular margin should not remain our only determinant of the success of a curative-intent surgery for patients with cancer. Based on current evidence, relying on a purely cellular focus to provide a binary indication of treatment success can provide an incomplete interpretation of potential outcome. A more holistic analysis of the cancer margin may be required. If we are to move ahead from our current situation - and allow treatment plans to be more intelligently tailored to meet the requirements of each individual tumour - we need to improve our utilisation of techniques that either improve recognition of residual tumour cells within the surgical field or enable a more comprehensive interrogation of tumour biology that identifies a risk of recurrence. In the second article in this series on defining the relevance of surgical margins, the authors discuss possible alternative strategies for margin assessment and evaluation in the canine and feline cancer patient. These strategies include considering adoption of the residual tumour classification scheme; intra-operative imaging systems including fluorescence-guided surgery, optical coherence tomography and Raman spectroscopy; molecular analysis and whole transcriptome analysis of tissues; and the development of a biologic index (nomogram). These techniques may allow evaluation of individual tumour biology and the status of the resection margin in ways that are different to our current techniques. Ultimately, these techniques seek to better define the risk of tumour recurrence following surgery and provide the surgeon and patient with more confidence in margin assessment.

Clinical advancement of precision theranostics in prostate cancer

Theranostic approaches with positron emission tomography/computed tomography (PET/CT) or PET/magnetic resonance imaging (PET/MRI) molecular imaging probes are being implemented clinically in prostate cancer (PCa) diagnosis and imaging-guided precision surgery. This review article provides a comprehensive summary of the rapidly expanding list of molecular imaging probes in this field, including their applications in early diagnosis of primary prostate lesions; detection of lymph node, skeletal and visceral metastases in biochemical relapsed patients; and intraoperative guidance for tumor margin detection and nerve preservation. Although each imaging probe shows preferred efficacy in some applications and limitations in others, the exploration and research efforts in this field will eventually lead to improved precision theranostics of PCa.

Practical Guidance for Developing Small-Molecule Optical Probes for In Vivo Imaging

The WMIS Education Committee (2019-2022) reached a consensus that white papers on molecular imaging could be beneficial for practitioners of molecular imaging at their early career stages and other scientists who are interested in molecular imaging. With this consensus, the committee plans to publish a series of white papers on topics related to the daily practice of molecular imaging. In this white paper, we aim to provide practical guidance that could be helpful for optical molecular imaging, particularly for small molecule probe development and validation in vitro and in vivo. The focus of this paper is preclinical animal studies with small-molecule optical probes. Near-infrared fluorescence imaging, bioluminescence imaging, chemiluminescence imaging, image-guided surgery, and Cerenkov luminescence imaging are discussed in this white paper.

Three-Dimensional Near-Infrared Specimen Mapping Can Identify the Distance from the Tumor to the Surgical Margin During Resection of Pulmonary Ground Glass Opacities

BACKGROUND

Lung cancers can recur locally due to inadequate resection margins. Achieving adequate margin distances is challenging in pulmonary ground glass opacities (GGOs) because they are not easily palpable. To improve margin assessment during resection of GGOs, we propose a novel technique, three-dimensional near-infrared specimen mapping (3D-NSM).

METHODS

Twenty patients with a cT1 GGO were enrolled and received a fluorescent tracer preoperatively. After resection, specimens underwent 3D-NSM in the operating room. Margins were graded as positive or negative based upon fluorescence at the staple line. Images were analyzed using ImageJ to quantify the distance from the tumor edge to the nearest staple line. This margin distance calculated by 3D-NSM was compared to the margin distance reported on final pathology several days postoperatively.

RESULTS

3D-NSM identified 20/20 GGOs with no false positive or false negative diagnoses. Mean fluorescence intensity for lesions was 110.92 arbitrary units (A.U.) (IQR: 77.77-122.03 A.U.) compared to 23.68 A.U. (IQR: 19.60-27.06 A.U.) for background lung parenchyma (p < 0.0001). There were 4 tumor-positive or close margins in the study cohort, and all 4 (100%) were identified by 3D-NSM. 3D-NSM margin distances were nearly identical to margin distances reported on final pathology (R2 = 0.9362). 3D-NSM slightly under-predicted margin distance, and the median difference in margins was 1.9 mm (IQR 0.5-4.3 mm).

CONCLUSIONS

3D-NSM rapidly localizes GGOs by fluorescence and detects tumor-positive or close surgical margins. 3D-NSM can accurately quantify the resection margin distance as compared to formal pathology, which allows surgeons to rapidly determine whether sublobar resection margin distances are adequate.

Comparison of Five Near-Infrared Fluorescent Folate Conjugates in an Ovarian Cancer Model

PURPOSE

Fluorescence imaging (FLI) using targeted near-infrared (NIR) conjugates aids the detection of tumour lesions pre- and intraoperatively. The optimisation of tumour visualisation and contrast is essential and can be achieved through high tumour-specificity and low background signal. However, the choice of fluorophore is recognised to alter biodistribution and clearance of conjugates and is therefore a determining factor in the specificity of target binding. Although ZW800-1, IRDye® 800CW and ICG are the most commonly employed NIR fluorophores in clinical settings, the fluorophore with optimal in vivo characteristics has yet to be determined. Therefore, we aimed to characterise the impact the choice of fluorophore has on the biodistribution, specificity and contrast, by comparing five different NIR fluorophores conjugated to folate, in an ovarian cancer model.

PROCEDURES

ZW800-1, ZW800-1 Forte, IRDye® 800CW, ICG-OSu and an in-house synthesised Cy7 derivative were conjugated to folate through an ethylenediamine linker resulting in conjugates 1-5, respectively. The optical properties of all conjugates were determined by spectroscopy, the specificity was assessed in vitro by flow cytometry and FLI, and the biodistribution was studied in vivo and ex vivo in a subcutaneous Skov-3 ovarian cancer model.

RESULTS

We demonstrated time- and receptor-dependent binding of folate conjugates in vitro and in vivo. Healthy tissue clearance characteristics and tumour-specific signal varied between conjugates 1-5. ZW800-1 Forte (2) revealed the highest contrast in folate receptor alpha (FRα)-positive xenografts and showed statistically significant target specificity. While conjugates 1, 2 and 3 are renally cleared, hepatobiliary excretion and no or very low accumulation in tumours was observed for 4 and 5.

CONCLUSIONS

The choice of fluorophore has a significant impact on the biodistribution and tumour contrast. ZW800-1 Forte (2) exhibited the best properties of those tested, with significant specific fluorescence signal.

Application of indocyanine green (ICG)-guided surgery in clinical practice: lesson to learn from other organs-an overview on clinical applications and future perspectives

Indocyanine green (ICG) fluorescence-guided surgery is a modality of intra-operative navigation that might support the surgeon with enhanced visualization of anatomical structures in real time. Over the last years, it has emerged as one of the most promising and rapidly developing technical innovations in surgery. The most popular current clinical applications include fluorescence cholangiography, bowel anastomotic perfusion assessment, fluorescence-guided lymphography for sentinel lymph-node identification and guided lymphadenectomy and the possible use in oncological surgery for the identification and localization of tumors and the diagnosis and treatment of peritoneal carcinosis. This paper provides an overview of the multiple fields of applications of ICG fluorescence-guided surgery in visceral and oncological surgery, discussing indications summarizing most recent and significative available literature and giving technical notes of use.

Perivascular epithelioid cell tumors of the liver misdiagnosed as hepatocellular carcinoma: Three case reports

BACKGROUND

Hepatic perivascular epithelioid cell neoplasms (PEComas) are rare. Diagnostic and treatment experience with hepatic PEComa remains insufficient.

CASE SUMMARY

Three hepatic PEComa cases are reported in this paper: One case of primary malignant hepatic PEComa, one case of benign hepatic PEComa, and one case of hepatic PEComa with an ovarian mature cystic teratoma. During preoperative imaging and pathological assessment of intraoperative frozen samples, patients were diagnosed with hepatocellular carcinoma (HCC), while postoperative pathology and immunohistochemistry subsequently revealed hepatic PEComa. Patients with hepatic PEComa which is misdiagnosed as HCC often require a wider surgical resection. It is easy to mistake them for distant metastases of hepatic PEComa and misdiagnosed as HCC, especially when it's combined with tumors in other organs. Three patients eventually underwent partial hepatectomy. After 1-4 years of follow-up, none of the patients experienced recurrence or metastases.

CONCLUSION

A clear preoperative diagnosis of hepatic PEComa can reduce the scope of resection and prevent unnecessary injuries during surgery.

Intraoperative Molecular Fluorescence Imaging of Pancreatic Cancer by Targeting Vascular Endothelial Growth Factor: A Multicenter Feasibility Dose-Escalation Study

Tumor visualization with near-infrared fluorescence (NIRF) imaging might aid exploration and resection of pancreatic cancer by visualizing the tumor in real time. Conjugation of the near-infrared fluorophore IRDye800CW to the monoclonal antibody bevacizumab enables targeting of vascular endothelial growth factor A. The aim of this study was to determine whether intraoperative tumor-specific imaging of pancreatic cancer with the fluorescent tracer bevacizumab-800CW is feasible and safe. Methods: In this multicenter dose-escalation phase I trial, patients in whom pancreatic ductal adenocarcinoma (PDAC) was suspected were administered bevacizumab-800CW (4.5, 10, or 25 mg) 3 d before surgery. Safety monitoring encompassed allergic or anaphylactic reactions and serious adverse events attributed to bevacizumab-800CW. Intraoperative NIRF imaging was performed immediately after laparotomy, just before and after resection of the specimen. Postoperatively, fluorescence signals on the axial slices and formalin-fixed paraffin-embedded tissue blocks from the resected specimens were correlated with histology. Subsequently, tumor-to-background ratios (TBR) were calculated. Results: Ten patients with clinically suspected PDAC were enrolled in the study. Four of the resected specimens were confirmed PDACs; other malignancies were distal cholangiocarcinoma, ampullary carcinoma, and neuroendocrine tumors. No serious adverse events were related to bevacizumab-800CW. In vivo tumor visualization with NIRF imaging differed per tumor type and was nonconclusive. Ex vivo TBRs were 1.3, 1.5, and 2.5 for the 4.5-, 10-, and 25-mg groups, respectively. Conclusion: NIRF-guided surgery in patients with suspected PDAC using bevacizumab-IRDye800CW is feasible and safe. However, suboptimal TBRs were obtained because no clear distinction between pancreatic cancer from normal or inflamed pancreatic tissue was achieved. Therefore, a more tumor-specific tracer than bevacizumab-IRDye800CW for PDAC is preferred.

Autofluorescence Image-Guided Endoscopy in the Management of Upper Aerodigestive Tract Tumors

At this juncture, autofluorescence and narrow-band imaging have resurfaced in the medicine arena in parallel with current technology advancement. The emergence of newly developed optical instrumentation in addition to the discovery of new fluorescence biomolecules have contributed to a refined management of diseases and tumors, especially in the management of upper aerodigestive tract tumors. The advancement in multispectral imaging and micro-endoscopy has also escalated the trends further in the setting of the management of this tumor, in order to gain not only the best treatment outcomes but also facilitate early tumor diagnosis. This includes the usage of autofluorescence endoscopy for screening, diagnosis and treatment of this tumor. This is crucial, as microtumoral deposit at the periphery of the gross tumor can be only assessed via an enhanced endoscopy and even more precisely with autofluorescence endoscopic techniques. Overall, with this new technique, optimum management can be achieved for these patients. Hence, the treatment outcomes can be improved and patients are able to attain better prognosis and survival.

Intraoperative Tumor Detection Using Pafolacianine

Cancer is a leading cause of death worldwide, with increasing numbers of new cases each year. For the vast majority of cancer patients, surgery is the most effective procedure for the complete removal of the malignant tissue. However, relapse due to the incomplete resection of the tumor occurs very often, as the surgeon must rely primarily on visual and tactile feedback. Intraoperative near-infrared imaging with pafolacianine is a newly developed technology designed for cancer detection during surgery, which has been proven to show excellent results in terms of safety and efficacy. Therefore, pafolacianine was approved by the U.S. Food and Drug Administration (FDA) on 29 November 2021, as an additional approach that can be used to identify malignant lesions and to ensure the total resection of the tumors in ovarian cancer patients. Currently, various studies have demonstrated the positive effects of pafolacianine’s use in a wide variety of other malignancies, with promising results expected in further research. This review focuses on the applications of the FDA-approved pafolacianine for the accurate intraoperative detection of malignant tissues. The cancer-targeting fluorescent ligands can shift the paradigm of surgical oncology by enabling the visualization of cancer lesions that are difficult to detect by inspection or palpation. The enhanced detection and removal of hard-to-detect cancer tissues during surgery will lead to remarkable outcomes for cancer patients and society, specifically by decreasing the cancer relapse rate, increasing the life expectancy and quality of life, and decreasing future rates of hospitalization, interventions, and costs.

Targeted detection of cancer cells during biopsy allows real-time diagnosis of pulmonary nodules

Background

The diagnostic yield of biopsies of solitary pulmonary nodules (SPNs) is low, particularly in sub-solid lesions. We developed a method (NIR-nCLE) to achieve cellular level cancer detection during biopsy by integrating (i) near-infrared (NIR) imaging using a cancer-targeted tracer (pafolacianine), and (ii) a flexible NIR confocal laser endomicroscopy (CLE) system that can fit within a biopsy needle. Our goal was to assess the diagnostic accuracy of NIR-nCLE ex vivo in SPNs.

Methods

Twenty patients with SPNs were preoperatively infused with pafolacianine. Following resection, specimens were inspected to identify the lesion of interest. NIR-nCLE imaging followed by tissue biopsy was performed within the lesion and in normal lung tissue. All imaging sequences (n = 115) were scored by 5 blinded raters on the presence of fluorescent cancer cells and compared to diagnoses by a thoracic pathologist.

Results

Most lesions (n = 15, 71%) were adenocarcinoma-spectrum malignancies, including 7 ground glass opacities (33%). Mean fluorescence intensity (MFI) by NIR-nCLE for tumor biopsy was 20.6 arbitrary units (A.U.) and mean MFI for normal lung was 6.4 A.U. (p < 0.001). Receiver operating characteristic analysis yielded a high area under the curve for MFI (AUC = 0.951). Blinded raters scored the NIR-nCLE sequences on the presence of fluorescent cancer cells with sensitivity and specificity of 98% and 97%, respectively. Overall diagnostic accuracy was 97%. The inter-observer agreement of the five raters was excellent (κ = 0.95).

Conclusions

NIR-nCLE allows sensitive and specific detection of cancer cells in SPNs. This technology has far-reaching implications for diagnostic needle biopsies and intraprocedural decision-making.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-022-05868-9.

Fluorescence-Guided Surgery (FGS) during a Laparoscopic Redo Nissen Fundoplication: The First Case in Children

We present the first case of fluorescence-guided surgery (FGS) using indocyanine green (ICG) in a pediatric redo-Nissen fundoplication. The patient is a 17-year-old male with recurrent gastroesophageal symptoms who underwent primary antireflux surgery at 10 months of age. During the redo fundoplication, ICG was intravenously administered to help the visualization during the adhesiolysis between liver, stomach and right crus of the diaphragm and to spare small oesophageal vessels and the left gastric artery. In this case, FGS made the surgery easier than usual and likely reduced the risk of intra-operative complications. Therefore, we believe that this new technology should be regularly used in these types of complex intra-abdominal redo operations.

Targeted detection of cancer at the cellular level during biopsy by near-infrared confocal laser endomicroscopy

Suspicious nodules detected by radiography are often investigated by biopsy, but the diagnostic yield of biopsies of small nodules is poor. Here we report a method-NIR-nCLE-to detect cancer at the cellular level in real-time during biopsy. This technology integrates a cancer-targeted near-infrared (NIR) tracer with a needle-based confocal laser endomicroscopy (nCLE) system modified to detect NIR signal. We develop and test NIR-nCLE in preclinical models of pulmonary nodule biopsy including human specimens. We find that the technology has the resolution to identify a single cancer cell among normal fibroblast cells when co-cultured at a ratio of 1:1000, and can detect cancer cells in human tumors less than 2 cm in diameter. The NIR-nCLE technology rapidly delivers images that permit accurate discrimination between tumor and normal tissue by non-experts. This proof-of-concept study analyzes pulmonary nodules as a test case, but the results may be generalizable to other malignancies.

Unique Properties of Surface-Functionalized Nanoparticles for Bio-Application: Functionalization Mechanisms and Importance in Application

This review tries to summarize the purpose of steadily developing surface-functionalized nanoparticles for various bio-applications and represents a fascinating and rapidly growing field of research. Due to their unique properties—such as novel optical, biodegradable, low-toxicity, biocompatibility, size, and highly catalytic features—these materials are considered superior, and it is thus vital to study these systems in a realistic and meaningful way. However, rapid aggregation, oxidation, and other problems are encountered with functionalized nanoparticles, inhibiting their subsequent utilization. Adequate surface modification of nanoparticles with organic and inorganic compounds results in improved physicochemical properties which can overcome these barriers. This review investigates and discusses the iron oxide nanoparticles, gold nanoparticles, platinum nanoparticles, silver nanoparticles, and silica-coated nanoparticles and how their unique properties after fabrication allow for their potential use in a wide range of bio-applications such as nano-based imaging, gene delivery, drug loading, and immunoassays. The different groups of nanoparticles and the advantages of surface functionalization and their applications are highlighted here. In recent years, surface-functionalized nanoparticles have become important materials for a broad range of bio-applications.

Biodegradable Nanoprobe for NIR-II Fluorescence Image-Guided Surgery and Enhanced Breast Cancer Radiotherapy Efficacy

Positive resection margin frequently exists in breast-conserving treatment (BCT) of early-stage breast cancer, and insufficient therapeutic efficacy is common during radiotherapy (RT) in advanced breast cancer patients. Moreover, a multimodal nanotherapy platform is urgently required for precision cancer medicine. Therefore, a biodegradable cyclic RGD pentapeptide/hollow virus-like gadolinium (Gd)-based indocyanine green (R&HV-Gd@ICG) nanoprobe is developed to improve fluorescence image-guided surgery and breast cancer RT efficacy. R&HV-Gd exhibits remarkably improved aqueous stability, tumor retention, and target specificity of ICG, and achieves outstanding magnetic resonance/second near-infrared (NIR-II) window multimodal imaging in vivo. The nanoprobe-based NIR-II fluorescence image guidance facilitates complete tumor resection, improves the overall mouse survival rate, and effectively discriminates between benign and malignant breast tissues in spontaneous breast cancer transgenic mice (area under the curve = 0.978; 95% confidence interval: 0.952, 1.0). Moreover, introducing the nanoprobe to tumors generated more reactive oxygen species under X-ray irradiation, improved RT sensitivity, and reduced mouse tumor progression. Notably, the nanoprobe is biodegradable in vivo and exhibits accelerated bodily clearance, which is expected to reduce the potential long-term inorganic nanoparticle toxicity. Overall, the nanoprobe provides a basis for developing precision breast cancer treatment strategies.

Intraoperative fluorescence molecular imaging accelerates the coming of precision surgery in China

Purpose

China has the largest cancer population globally. Surgery is the main choice for most solid cancer patients. Intraoperative fluorescence molecular imaging (FMI) has shown its great potential in assisting surgeons in achieving precise resection. We summarized the typical applications of intraoperative FMI and several new trends to promote the development of precision surgery.

Methods

The academic database and NIH clinical trial platform were systematically evaluated. We focused on the clinical application of intraoperative FMI in China. Special emphasis was placed on a series of typical studies with new technologies or high-level evidence. The emerging strategy of combining FMI with other modalities was also discussed.

Results

The clinical applications of clinically approved indocyanine green (ICG), methylene blue (MB), or fluorescein are on the rise in different surgical departments. Intraoperative FMI has achieved precise lesion detection, sentinel lymph node mapping, and lymphangiography for many cancers. Nerve imaging is also exploring to reduce iatrogenic injuries. Through different administration routes, these fluorescent imaging agents provided encouraging results in surgical navigation. Meanwhile, designing new cancer-specific fluorescent tracers is expected to be a promising trend to further improve the surgical outcome.

Conclusions

Intraoperative FMI is in a rapid development in China. In-depth understanding of cancer-related molecular mechanisms is necessary to achieve precision surgery. Molecular-targeted fluorescent agents and multi-modal imaging techniques might play crucial roles in the era of precision surgery.

Development and Preclinical Evaluation of a Near-Infrared Fluorescence Probe Based on Tailored Hepatitis B Core Particles for Imaging-Guided Surgery in Breast Cancer

PURPOSE

Tumor-free surgical margin is crucial but challenging in breast-conserving surgery (BCS). Fluorescence imaging is a promising strategy for surgical navigation that can reliably assist the surgeon with visualization Of the tumor in real-time. Notably, finding an optimized fluorescent probe has been a challenging research topic. Herein, we developed a novel near-infrared (NIR) fluorescent probe based on tailored Hepatitis B Core virus-like protein (HBc VLP) and presented the preclinical imaging-guided surgery.

METHODS

The RGD-HBc₁₆₀ VLP was synthesized by genetic engineering followed encapsulation of ICG via disassembly-reassembly. The applicability of the probe was tested for cell and tissue binding capacities through cell-based plate assays, xenograft mice model, and MMTV-PyVT mammary tumor transgenic mice. Subsequently, the efficacy of RGD-HBc₁₆₀/ICG-guided surgery was evaluated in an infiltrative tumor-bearing mouse model. The protein-induced body's immune response was further assessed.

RESULTS

The prepared RGD-HBc₁₆₀/ICG showed outstanding integrin α_vβ₃ targeting ability in vitro and in vivo. After intravenous administration of probe, the fluorescence guidance facilitated more complete tumor resection and improved overall survival Of the infiltrative tumor-bearing mice. The probe also showed the excellent capability to differentiate between benign and malignant breast tissues in the mammary tumor transgenic mice. Interestingly, the ingenious tailoring of HBc VLP could not only endow its tumor-targeting ability towards integrin α_vβ₃ but also significantly reduce the humoral and cellular immune response.

CONCLUSION

The RGD-HBc₁₆₀/ICG holds promise as an effective tool to delineate tumor margin. These results have translational potential to achieve margin-negative resection and improve the stratification of patients for a potentially curative.

Image-guided surgery and novel intraoperative devices for enhanced visualisation in general and paediatric surgery: a review

Fluorescence guided surgery, augmented reality, and intra-operative imaging devices are rapidly pervading the field of surgical interventions, equipping the surgeon with powerful tools capable of enhancing the surgical visualisation of anatomical normal and pathological structures. There is a wide range of possibilities in the adult population to use these novel technologies and devices in the guidance for surgical procedures and minimally invasive surgeries. Their applications and their use have also been increasingly growing in the field of paediatric surgery, where the detailed visualisation of small anatomical structures could reduce procedure time, minimising surgical complications and ultimately improve the outcome of surgery. This review aims to illustrate the mechanisms underlying these innovations and their main applications in the clinical setting.

Polymeric Micro/Nanocarriers and Motors for Cargo Transport and Phototriggered Delivery

Smart polymer-based micro/nanoassemblies have emerged as a promising alternative for transporting and delivering a myriad of cargo. Cargo encapsulation into (or linked to) polymeric micro/nanocarrier (PC) strategies may help to conserve cargo activity and functionality when interacting with its surroundings in its journey to the target. PCs for cargo phototriggering allow for excellent spatiotemporal control via irradiation as an external stimulus, thus regulating the delivery kinetics of cargo and potentially increasing its therapeutic effect. Micromotors based on PCs offer an accelerated cargo-medium interaction for biomedical, environmental, and many other applications. This review collects the recent achievements in PC development based on nanomicelles, nanospheres, and nanopolymersomes, among others, with enhanced properties to increase cargo protection and cargo release efficiency triggered by ultraviolet (UV) and near-infrared (NIR) irradiation, including light-stimulated polymeric micromotors for propulsion, cargo transport, biosensing, and photo-thermal therapy. We emphasize the challenges of positioning PCs as drug delivery systems, as well as the outstanding opportunities of light-stimulated polymeric micromotors for practical applications.

3D Specimen Mapping Expedites Frozen Section Diagnosis of Non-Palpable Ground Glass Opacities

BACKGROUND

Pulmonary ground glass opacities (GGOs) are early-stage adenocarcinoma spectrum lesions that are not easily palpable. Challenges in localizing GGOs during intraoperative pathology can lead to imprecise diagnoses and additional time under anesthesia. To improve localization of GGOs during frozen section diagnosis, we evaluated a novel technique, three-dimensional near-infrared specimen mapping (3D-NSM).

METHODS

Fifty-five patients with a cT1 GGO were enrolled and received a fluorescent tracer preoperatively. After resection, specimens were inspected to identify lesions. Palpable and non-palpable nodules underwent 3D-NSM and the area of highest fluorescence was marked with a suture. Time for 3D-NSM, time for frozen section diagnosis, and number of tissue sections examined were recorded. To compare 3D-NSM to standard-of-care techniques, a control cohort of twenty subjects with identical inclusion criteria were enrolled. Specimens did not undergo 3D-NSM and were sent directly to pathology.

RESULTS

3D-NSM localized 54/55 lesions with one false negative. All 41 palpable lesions were identified by 3D-NSM. Thirteen of 14 non-palpable lesions (92.8%) were located by 3D-NSM. Time to diagnosis for the 3D-NSM cohort was 23.5 minutes, compared to 26.0 minutes in the control cohort (p=0.04). 3D-NSM did not affect time to diagnosis of palpable lesions (23.2 min vs. 21.4 minutes, p=0.10). 3D-NSM significantly reduced time to diagnosis for non-palpable lesions (t=23.3 min vs. 34.4 minutes, p<0.0001). 3D-NSM also reduced the number of tissue sections analyzed in non-palpable lesions (4.50 vs. 11.00, p<0.0001).

CONCLUSIONS

3D-NSM accurately localizes GGOs and expedites intraoperative diagnosis by reducing the number of tissue sections analyzed for non-palpable GGOs.

Targeted Intraoperative Molecular Imaging for Localizing Nonpalpable Tumors and Quantifying Resection Margin Distances

Importance

Complete (R0) resection is the dominant prognostic factor for survival across solid tumor types. Achieving adequate tumor clearance with appropriate margins is particularly difficult in nonpalpable tumors or in situ disease. Previous methods to address this problem have proven time consumptive, impractical, or ineffective.

Objective

To assess the capability of intraoperative molecular imaging (IMI), a novel technology using a fluorescent tracer targeted to malignant cells, to localize visually occult, nonpalpable tumors and quantify margin distances during resection.

Design, Setting, and Participants

This nonrandomized open-label trial of IMI using a folate receptor-targeted fluorescent tracer enrolled patients between May 2017 and June 2020 at a single referral center. Eligible patients included those with a small (T1) lung lesion suspicious for malignant neoplasms and with radiographic features suggestive of a nonpalpable lesion.

Interventions

Patients were preoperatively infused with a folate receptor-targeted near-infrared tracer. Intraoperatively, surgeons used thoracoscopic visualization and palpation to identify lesions. IMI was performed to detect the lesion in situ, and lesions were imaged ex vivo. Margins were assessed by IMI before comparison with those reported on final histopathologic analysis.

Main Outcomes and Measures

The main outcomes were whether IMI could (1) localize nonpalpable lung lesions in situ and (2) quantify margin distance with comparison with final pathology as the criterion standard. Patient demographic information and lesion characteristics were prospectively recorded.

Results

Of 40 patients, 26 (65%) were female, and the median (interquartile range) age was 66.5 (62-72) years. Conventional surgical methods localized 22 of 40 lesions (55%), while IMI localized 36 of 40 (90%). Of 18 nonpalpable lesions, 15 (83.3%) were identified by IMI. Both palpable and nonpalpable lesions demonstrated mean signal-to-background ratio more than 2. An IMI margin was able to be calculated for 39 of 40 patients (95%). IMI margins were nearly identical to margins reported on final pathology (R2 = 0.9593), with median (interquartile range) difference of 1.3 (0.7-2.0) mm. IMI detected 2 margins in nonpalpable tumors that were clinically unacceptable and would have had a high probability of recurrence.

Conclusions and Relevance

To our knowledge, this study presents the first clinical use of IMI for nonpalpable tumors and provides proof of principle for the utility of IMI across the field of surgical oncology in identifying occult disease and tumor-positive margins.

Diagnostic accuracy of in vivo early tumor imaging from probe-based confocal laser endomicroscopy versus histologic examination in head and neck squamous cell carcinoma

OBJECTIVES

Probe-based confocal laser endomicroscopy (pCLE) is a noninvasive and real-time imaging technique allowing acquisition of in situ images of the tissue microarchitecture during oral surgery. We aimed to assess the diagnostic performance of pCLE combined with patent blue V (PB) in improving the management of early oral cavity, oro/hypopharyngeal, and laryngeal cancer by imaging squamous cell carcinoma in vivo.

MATERIALS AND METHODS

The prospective study enrolled 44 patients with early head and neck lesions. All patients underwent white-light inspection or panendoscopy depending on the lesion's location, followed by pCLE imaging of the tumor core and its margins after topical application of PB. Each zone imaged by pCLE was interpreted at distance of the exam by three pathologists blinded to final histology.

RESULTS

Most imaged zones could be presented to pathologists; the final sensitivity and specificity of pCLE imaging in head and neck cancers was 73.2-75% and 30-57.4%, respectively. During imaging, head and neck surgeons encountered some challenges that required resolving, such as accessing lesions with the flexible optical probe, achieving sufficiently precise imaging on the targeted tissues, and heterogeneous tissue staining by fluorescent dye.

CONCLUSION

Final sensitivity scores were reasonable but final specificity scores were low. pCLE zones used to calculate specificity were acquired in areas of tumor margins, and the poor quality of the images acquired in these areas explains the final low specificity scores.

CLINICAL RELEVANCE

Practical adjustments and technical training are needed to analyze head and neck lesions in various anatomical sites in real-time by pCLE.

Subset of Fluorophores Is Responsible for Radiation Brightening in Viromimetic Particles

In certain conditions, dye-conjugated icosahedral virus shells exhibit suppression of concentration quenching. The recently observed radiation brightening at high fluorophore densities has been attributed to coherent emission, i.e., to a cooperative process occurring within a subset of the virus-supported fluorophores. Until now, the distribution of fluorophores among potential conjugation sites and the nature of the active subset remained unknown. With the help of mass spectrometry and molecular dynamics simulations, we found which conjugation sites in the brome mosaic virus capsid are accessible to fluorophores. Reactive external surface lysines but also those at the lumenal interface where the coat protein N-termini are located showed virtually unrestricted access to dyes. The third type of labeled lysines was situated at the intercapsomeric interfaces. Through limited proteolysis of flexible N-termini, it was determined that dyes bound to them are unlikely to be involved in the radiation brightening effect. At the same time, specific labeling of genetically inserted cysteines on the exterior capsid surface alone did not lead to radiation brightening. The results suggest that lysines situated within the more rigid structural part of the coat protein provide the chemical environments conducive to radiation brightening, and we discuss some of the characteristics of these environments.

Short-Wave Infrared Emitting Nanocomposites for Fluorescence-Guided Surgery

Fluorescence-guided surgery (FGS) is an emerging technique for tissue visualization during surgical procedures. Structures of interest are labeled with exogenous probes whose fluorescent emissions are acquired and viewed in real-time with optical imaging systems. This study investigated rare-earth-doped albumin-encapsulated nanocomposites (REANCs) as short-wave infrared emitting contrast agents for FGS. Experiments were conducted using an animal model of 4T1 breast cancer. The signal-to-background ratio (SBR) obtained with REANCs was compared to values obtained using indocyanine green (ICG), a near-infrared dye used in clinical practice. Prior to resection, the SBR for tumors following intratumoral administration of REANCs was significantly higher than for tumors injected with ICG. Following FGS, evaluation of fluorescence intensity levels in excised tumors and at the surgical bed demonstrated higher contrast between tissues at these sites with REANC contrast than ICG. REANCs also demonstrated excellent photostability over 2 hours of continuous illumination, as well as the ability to perform FGS under ambient lighting, establishing these nanocomposites as a promising contrast agent for FGS applications.

Surgical navigation for challenging recurrent or pretreated intra-abdominal and pelvic soft tissue sarcomas

BACKGROUND

This study assessed whether electromagnetic navigation can be of added value during resection of recurrent or post-therapy intra-abdominal/pelvic soft tissue sarcomas (STS) in challenging locations.

MATERIALS AND METHODS

Patients were included in a prospective navigation study. A pre-operatively 3D roadmap was made and tracked using electromagnetic reference markers. During the operation, an electromagnetic pointer was used for the localization of the tumor/critical anatomical structures. The primary endpoint was feasibility, secondary outcomes were safety and usability.

RESULTS

Nine patients with a total of 12 tumors were included, 7 patients with locally recurrent sarcoma. Three patients received neoadjuvant radiotherapy and three other patients received neoadjuvant systemic treatment. The median tumor size was 4.6 cm (2.4-10.4). The majority of distances from tumor to critical anatomical structures was <0.5 cm. The tumors were localized using the navigation system without technical or safety issues. Despite the challenging nature of these resections, 89% were R0 resections, with a median blood loss of 100 ml (20-1050) and one incident of vascular damage. Based on the survey, surgeons stated navigation resulted in shorter surgery time and made the resections easier.

CONCLUSION

Electromagnetic navigation facilitates resections of challenging lower intra-abdominal/pelvic STS and might be of added value.

Nanoparticle Formulation of Indocyanine Green Improves Image-Guided Surgery in a Murine Model of Breast Cancer

PURPOSE

Negative surgical margins (NSMs) have favorable prognostic implications in breast tumor resection surgery. Fluorescence image-guided surgery (FIGS) has the ability to delineate surgical margins in real time, potentially improving the completeness of tumor resection. We have recently developed indocyanine green (ICG)-loaded self-assembled hyaluronic acid (HA) nanoparticles (NanoICG) for solid tumor imaging, which were shown to enhance intraoperative contrast.

PROCEDURES

This study sought to assess the efficacy of NanoICG on completeness of breast tumor resection and post-surgical survival. BALB/c mice bearing iRFP⁺/luciferase⁺ 4T1 syngeneic breast tumors were administered NanoICG or ICG, underwent FIGS, and were compared to bright light surgery (BLS) and sham controls.

RESULTS

NanoICG increased the number of complete resections and improved tumor-free survival. This was a product of improved intraoperative contrast enhancement and the identification of a greater number of small, occult lesions than ICG and BLS. Additionally, NanoICG identified chest wall invasion and predicted recurrence in a model of late-stage breast cancer.

CONCLUSIONS

NanoICG is an efficacious intraoperative contrast agent and could potentially improve surgical outcomes in breast cancer.

Receptor-Targeted Fluorescence-Guided Surgery With Low Molecular Weight Agents

Cancer surgery remains the primary treatment option for most solid tumors and can be curative if all malignant cells are removed. Surgeons have historically relied on visual and tactile cues to maximize tumor resection, but clinical data suggest that relapse occurs partially due to incomplete cancer removal. As a result, the introduction of technologies that enhance the ability to visualize tumors in the operating room represents a pressing need. Such technologies have the potential to revolutionize the surgical standard-of-care by enabling real-time detection of surgical margins, subclinical residual disease, lymph node metastases and synchronous/metachronous tumors. Fluorescence-guided surgery (FGS) in the near-infrared (NIRF) spectrum has shown tremendous promise as an intraoperative imaging modality. An increasing number of clinical studies have demonstrated that tumor-selective FGS agents can improve the predictive value of fluorescence over non-targeted dyes. Whereas NIRF-labeled macromolecules (i.e., antibodies) spearheaded the widespread clinical translation of tumor-selective FGS drugs, peptides and small-molecules are emerging as valuable alternatives. Here, we first review the state-of-the-art of promising low molecular weight agents that are in clinical development for FGS; we then discuss the significance, application and constraints of emerging tumor-selective FGS technologies.

Novel imaging techniques for intraoperative margin assessment in surgical oncology: A systematic review

Inadequate margins continue to occur frequently in patients who undergo surgical resection of a tumor, suggesting that current intraoperative methods are not sufficiently reliable in determining the margin status. This clinical demand has inspired the development of many novel imaging techniques that could help surgeons with intraoperative margin assessment. This systematic review provides an overview of novel imaging techniques for intraoperative margin assessment in surgical oncology, and reports on their technical properties, feasibility in clinical practice and diagnostic accuracy. PubMed, Embase, Web of Science and the Cochrane library were systematically searched (2013‐2018) for studies reporting on imaging techniques for intraoperative margin assessment. Patient and study characteristics, technical properties, feasibility characteristics and diagnostic accuracy were extracted. This systematic review identified 134 studies that investigated and developed 16 groups of techniques for intraoperative margin assessment: fluorescence, advanced microscopy, ultrasound, specimen radiography, optical coherence tomography, magnetic resonance imaging, elastic scattering spectroscopy, bio‐impedance, X‐ray computed tomography, mass spectrometry, Raman spectroscopy, nuclear medicine imaging, terahertz imaging, photoacoustic imaging, hyperspectral imaging and pH measurement. Most studies were in early developmental stages (IDEAL 1 or 2a, n = 98); high‐quality stage 2b and 3 studies were rare. None of the techniques was found to be clearly superior in demonstrating high feasibility as well as high diagnostic accuracy. In conclusion, the field of imaging techniques for intraoperative margin assessment is highly evolving. This review provides a unique overview of the opportunities and limitations of the currently available imaging techniques.

What's new?

While surgical resection is critical in the treatment of primary solid tumors, resection at tumor margins remains problematic, with inadequately resected margins facilitating tumor recurrence. In this systematic review, the authors collected information on novel imaging techniques applied to the intraoperative assessment of tumor margins across cancer types. A total of 16 groups of techniques were identified, with many in early stages of clinical application. Following comparison, no single technique was clearly superior in clinical feasibility or diagnostic accuracy. The review highlights the evolving nature of imaging techniques for intraoperative margin assessment and identifies opportunities and limitations in the field.

A path toward the clinical translation of nano-based imaging contrast agents

Recently, nanoparticles have evolved ubiquitously in therapeutic applications to treat a range of diseases. Despite their regular use as therapeutic agents in the clinic, we have yet to see much progress in their clinical translation as diagnostic imaging agents. Several clinical and preclinical studies support their use as imaging contrast agents, but their use in the clinical setting has been limited to off-label imaging procedures (i.e., Feraheme). Since diagnostic imaging has been historically used as an exploratory tool to rule out disease or to screen patients for various cancers, nanoparticle toxicity remains a concern, especially when introducing exogenous contrast agents into a potentially healthy patient population, perhaps rationalizing why several nano-based therapeutic agents have been clinically translated before nano-based imaging agents. Another potential hindrance toward their clinical translation could be their market potential, as most therapeutic drugs have higher earning potential than small-molecule imaging contrast agents. With these considerations in mind, perhaps a clinical path forward for nano-based imaging contrast agents is to help guide/manage therapy. Several studies have demonstrated the ability of nanoparticles to produce more accurate imaging preoperatively, intraoperatively, and postoperatively. These applications illustrate a more reliable method of cancer detection and treatment that can prevent incomplete tumor resection and incorrect assessment of tumor progression following treatment. The aim of this review is to highlight the research that supports the use of nanoparticles in biomedical imaging applications and offer a new perspective to illustrate how nano-based imaging agents have the potential to better inform therapeutic decisions. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

A near-infrared emitting MOF: controlled encapsulation of a fluorescein sensitizer at the time of crystal growth

We report here a near-infrared (NIR) emitting lanthanide-based metal-organic framework (MOF) in which Yb³⁺ are sensitized by fluorescein (FL) as a low energy absorbing chromophore (FL@CD-MOF-161). The unique design of CD-MOF-161 allows for the entrapment of FL molecules in its pores during the synthesis and crystal growth, ensuring the efficient loading and spreading of chromophores within the crystal volume.

Fluorescence imaging in pediatric surgery: State-of-the-art and future perspectives

BACKGROUND

The employment of fluorescence imaging has gained popularity in many fields of adult surgery where it has demonstrated great potentials to improve both surgical and oncological outcomes while minimizing anesthetic time and lowering health-care costs. However, the clinical application of fluorescence-guided surgery (FGS) in pediatrics is just at the initial phase.

MATERIAL AND METHODS

A systematic review of current clinical uses of FGS in pediatric surgery was performed along with a discussion on its advantages, limitations and future developments.

RESULTS

21 studies were included: 9 retrospective and 1 prospective study, 8 case reports, 2 case series and a review article reporting authors' institutional experience. Great emphasis was given to surgical resection of hepatoblastoma and its metastasis (n = 6), real-time imaging of the biliary tree (n = 3) and urogenital system (n = 2). Other current uses concern the assessment of blood perfusion (intestine, n = 3; myocutaneous flap, n = 1; transplanted liver, n = 1) and lymphatic flow imaging (n = 4).

CONCLUSION

Despite a paucity of clinical studies evaluating its role in pediatric surgery, FGS has shown promising results in helping guide tumor resection and improving the accuracy of anatomical delineation.

TYPE OF STUDY

Review article.

LEVEL OF CONFIDENCE

Level IV.