KEYWORDS: Tumors, Education and training, Deep learning, Voxels, Magnetic resonance imaging, Data modeling, Tissues, Resection, Brain, Cross validation
PurposeGlioblastoma (GBM) is the most common and aggressive primary adult brain tumor. The standard treatment approach is surgical resection to target the enhancing tumor mass, followed by adjuvant chemoradiotherapy. However, malignant cells often extend beyond the enhancing tumor boundaries and infiltrate the peritumoral edema. Traditional supervised machine learning techniques hold potential in predicting tumor infiltration extent but are hindered by the extensive resources needed to generate expertly delineated regions of interest (ROIs) for training models on tissue most and least likely to be infiltrated.ApproachWe developed a method combining expert knowledge and training-based data augmentation to automatically generate numerous training examples, enhancing the accuracy of our model for predicting tumor infiltration through predictive maps. Such maps can be used for targeted supra-total surgical resection and other therapies that might benefit from intensive yet well-targeted treatment of infiltrated tissue. We apply our method to preoperative multi-parametric magnetic resonance imaging (mpMRI) scans from a subset of 229 patients of a multi-institutional consortium (Radiomics Signatures for Precision Diagnostics) and test the model on subsequent scans with pathology-proven recurrence.ResultsLeave-one-site-out cross-validation was used to train and evaluate the tumor infiltration prediction model using initial pre-surgical scans, comparing the generated prediction maps with follow-up mpMRI scans confirming recurrence through post-resection tissue analysis. Performance was measured by voxel-wised odds ratios (ORs) across six institutions: University of Pennsylvania (OR: 9.97), Ohio State University (OR: 14.03), Case Western Reserve University (OR: 8.13), New York University (OR: 16.43), Thomas Jefferson University (OR: 8.22), and Rio Hortega (OR: 19.48).ConclusionsThe proposed model demonstrates that mpMRI analysis using deep learning can predict infiltration in the peri-tumoral brain region for GBM patients without needing to train a model using expert ROI drawings. Results for each institution demonstrate the model’s generalizability and reproducibility.
Liposomes have revolutionized the field of photomedicine. Photodynamic therapy (PDT) using Visudyne®, a liposomal photosensitizer formulation, has helped many patients globally. Since the FDA approved Visudyne® in 2002, countless studies have examined strategies to further improve the therapeutic index of lipid-based photosensitizing nanoconstructs. While liposomes can improve the pharmacokinetics of hydrophobic photosensitizers, they could also modulate cellular uptake and singlet oxygen production. Furthermore, it is evident that there are other immunological and toxicological considerations for the design of liposomal drugs. Accordingly, there is now an emerging trend to engineer carrier-free nanodrugs. Here, we developed a pure-drug nanoparticle using the clinically used verteporfin photosensitizer (termed nanoVP) for photodynamic applications. We validated the effects of nanoVP in three contexts: 1) cytotoxic PDT, 2) subtherapeutic PDT, and 3) dark toxicity. Using a brain cancer murine model, we showed that light activation of nanoVP reduced tumor volume by up to 54% compared to liposomal VP. Fluorescence imaging revealed that nanoVP had a superior tumor-to-liver tissue ratio (~0.92) compared to liposomal VP (~0.4). We further studied nanoVP-mediated PDT at subtherapeutic doses to achieve photodynamic priming (PDP). PDP has been shown to enhance drug delivery, activate antitumor immunity, and sensitize tumors to chemotherapy. This approach is particularly relevant in the brain, where high doses of PDT can result in edema, neurotoxicity, and even animal death. Using a rat model, we demonstrated that nanoVP-assisted PDP improved blood-brain barrier permeability and accumulation of a model drug (Evans Blue dye) in rat brains by >5 fold. Minimal to no brain damage was observed. Lastly, under dark conditions, we validated that nanoVP significantly reduced viability while liposomal VP stimulated cancer cell growth. Results from this work demonstrate the utility of nanoVP for cancer treatment. The development of pure-drug photosensitizing nanoparticles for photodynamic applications could further revolutionize the field of photomedicine.
Over the past few decades, considerable attention has been given to improving the photoactivity and biocompatibility of hydrophobic photosensitizing drugs for light-activatable biomedical applications. It is increasingly clear that photosensitizing biomolecules, based on chemical conjugation or association of photosensitizers with biomolecules (e.g., lipids, polymers, antibodies, and Pluronic), strongly influence the performance of a given photosensitizer in biological environments. However, the numerous studies that have revealed PSBMs are not readily comparable as they cover a wide range of macromolecules, evaluated across a range of experimental conditions. Here, we prepared and characterized a series of well-defined PSBMs and pure drug crystal based on a clinically used photosensitizer—benzoporphyrin derivative (BPD). Our results illuminate the variable trafficking and end effects of clinically relevant PSBMs and BPD nanocrystals, providing valuable insights into methods of PSMB evaluation as well as strategies to select PSMBs based on subcellular targets and cytotoxic mechanisms. More importantly, these results demonstrate that biologically-informed combinations of PSBMs and carrier-free photosensitizers to target multiple subcellular organelles may lead to enhanced therapeutic effects in gliomas.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.