A Bis-Boron Amino Acid for Positron Emission Tomography and Boron Neutron Capture Therapy.

Trifluoroborate boronophenylalanine (BBPA) is a boron amino acid analog of 4­boronophenylalanine (BPA) but with a trifluoroborate group (-BF3-) instead of a carboxyl group (-COOH). Clinical studies have shown that 18F-labeled BBPA ([18F]BBPA) can produce high-contrast tumor images in positron emission tomography (PET). Beyond PET imaging, BBPA is a theranostic agent for boron neutron capture therapy (BNCT). Because BBPA possesses an identical chemical structure to BNCT and PET, it can potentially predict the boron concentration for BNCT using [18F]BBPA-PET. The synthesis of BBPA was achieved by selectively fluorinating the α-aminoborate compound, taking advantage of the varying rates of solvolysis of the B-F bond. The study showcased the high-contrast [18F]BBPA-PET imaging in various tumor models, highlighting its broad applicability for both [18F]BBPA-PET and BBPA-BNCT. [18F]BBPA-PET tumor uptake remains consistent across various doses, including those used in BNCT. This enables accurate estimation of the boron concentration in tumors using [18F]BBPA-PET. With its dual boron structure, BBPA increases boron concentration in tumor cells and tumor tissues compared to BPA. Thus, less boron carrier is needed. This study introduces a new theranostic boron carrier that enhances boron accumulation in tumors, predicts boron concentration, and enhances the accuracy and effectiveness of BNCT.

A Metabolically Stable Boron-Derived Tyrosine Serves as a Theranostic Agent for Positron Emission Tomography Guided Boron Neutron Capture Therapy.

Boronophenylalanine (BPA) is the dominant boron delivery agent for boron neutron capture therapy (BNCT), and [18F]FBPA has been developed to assist the treatment planning for BPA-BNCT. However, the clinical application of BNCT has been limited by its inadequate tumor specificity due to the metabolic instability. In addition, the distinctive molecular structures between [18F]FBPA and BPA can be of concern as [18F]FBPA cannot quantitate boron concentration of BPA in a real-time manner. In this study, a metabolically stable boron-derived tyrosine (denoted as fluoroboronotyrosine, FBY) was developed as a theranostic agent for both boron delivery and cancer diagnosis, leading to PET imaging-guided BNCT of cancer. [18F]FBY was synthesized in high radiochemical yield (50%) and high radiochemical purity (98%). FBY showed high similarity with natural tyrosine. As shown in in vitro assays, the uptake of FBY in murine melanoma B16-F10 cells was L-type amino acid transporter (LAT-1) dependent and reached up to 128 µg/106 cells. FBY displayed high stability in PBS solution. [18F]FBY PET showed up to 6 %ID/g in B16-F10 tumor and notably low normal tissue uptake (tumor/muscle = 3.16 ± 0.48; tumor/blood = 3.13 ± 0.50; tumor/brain = 14.25 ± 1.54). Moreover, administration of [18F]FBY tracer along with a therapeutic dose of FBY showed high accumulation in B16-F10 tumor and low normal tissue uptake. Correlation between PET-image and boron biodistribution was established, indicating the possibility of estimating boron concentration via a noninvasive approach. At last, with thermal neutron irradiation, B16-F10 tumor-bearing mice injected with FBY showed significantly prolonged median survival without exhibiting obvious systemic toxicity. In conclusion, FBY holds great potential as an efficient theranostic agent for imaging-guided BNCT by offering a possible solution of measuring local boron concentration through PET imaging.

Boron neutron capture therapy for malignant melanoma: first clinical case report in China.

A phase I/II clinical trial for treating malignant melanoma by boron neutron capture therapy (BNCT) was designed to evaluate whether the world's first in-hospital neutron irradiator (IHNI) was qualified for BNCT. In this clinical trial planning to enroll 30 patients, the first case was treated on August 19, 2014. We present the protocol of this clinical trial, the treating procedure, and the clinical outcome of this first case. Only grade 2 acute radiation injury was observed during the first four weeks after BNCT and the injury healed after treatment. No late radiation injury was found during the 24-month follow-up. Based on positron emission tomography-computed tomography (PET/CT) scan, pathological analysis and gross examination, the patient showed a complete response to BNCT, indicating that BNCT is a potent therapy against malignant melanoma and IHNI has the potential to enable the delivery of BNCT in hospitals.

Exploring the Mechanisms of Traditional Chinese Herbal Therapy in Gastric Cancer: A Comprehensive Network Pharmacology Study of the Tiao-Yuan-Tong-Wei decoction.

The use of herbal medicine as an adjuvant therapy in the management of gastric cancer has yielded encouraging outcomes, notably in enhancing overall survival rates and extending periods of disease remission. Additionally, herbal medicines have demonstrated potential anti-metastatic effects in gastric cancer. Despite these promising findings, there remains a significant gap in our understanding regarding the precise pharmacological mechanisms, the identification of specific herbal compounds, and their safety and efficacy profiles in the context of gastric cancer therapy. In addressing this knowledge deficit, the present study proposes a comprehensive exploratory analysis of the Tiao-Yuan-Tong-Wei decoction (TYTW), utilizing an integrative approach combining system pharmacology and molecular docking techniques. This investigation aims to elucidate the pharmacological actions of TYTW in gastric pathologies. It is hypothesized that the therapeutic efficacy of TYTW in counteracting gastric diseases stems from its ability to modulate key signaling pathways, thereby influencing PIK3CA activity and exerting anti-inflammatory effects. This modulation is observed predominantly in pathways such as PI3K/AKT, MAPK, and those directly associated with gastric cancer. Furthermore, the study explores how TYTW's metabolites (agrimoniin, baicalin, corosolic acid, and luteolin) interact with molecular targets like AKT1, CASP3, ESR1, IL6, PIK3CA, and PTGS2, and their subsequent impact on these critical pathways and biological processes. Therefore, this study represents preliminary research on the anticancer molecular mechanism of TYTW by performing network pharmacology and providing theoretical evidence for further experimental investigations.

Quantitative proteomics of the miR-301a/SOCS3/STAT3 axis reveals underlying autism and anxiety-like behavior.

Autism is a widespread neurodevelopmental disorder. Although the research on autism spectrum disorders has been increasing in the past decade, there is still no specific answer to its mechanism of action and treatment. As a pro-inflammatory microRNA, miR-301a is abnormally expressed in various psychiatric diseases including autism. Here, we show that miR-301a deletion and inhibition exhibited two distinct abnormal behavioral phenotypes in mice. We observed that miR-301a deletion in mice impaired learning/memory, and enhanced anxiety. On the contrary, miR-301a inhibition effectively reduced the maternal immune activation (MIA)-induced autism-like behaviors in mice. We further demonstrated that miR-301a bound to the 3'UTR region of the SOCS3, and that inhibition of miR-301a led to the upregulation of SOCS3 in hippocampus. The last result in the reduction of the inflammatory response by inhibiting phosphorylation of AKT and STAT3, and the expression level of IL-17A in poly(I:C)-induced autism-like features in mice. The obtained data revealed the miR-301a as a critical participant in partial behavior phenotypes, which may exhibit a divergent role between gene knockout and knockdown. Our findings ascertain that miR-301a negatively regulates SOCS3 in MIA-induced autism in mice and could present a new therapeutic target for ameliorating the behavioral abnormalities of autism.

Plasma-generated RONS in liquid transferred into cryo-microneedles patch for skin treatment of melanoma.

Malignant melanoma is the most lethal form of skin cancer. As a promising anti-cancer agent, plasma-activated water (PAW) rich in reactive oxygen and nitrogen species (RONS) has shown significant potential for melanoma treatment. However, rapid decay of RONS and inefficient delivery of PAW in conventional injection methods limit its practical applications. To address this issue, here we report a new approach for the production of plasma-activated cryo-microneedles (PA-CMNs) patches using custom-designed plasma devices and processes. Our innovation is to incorporate PAW into the PA-CMNs that are fabricated using a fast cryogenic micro-molding method. It is demonstrated that PA-CMNs can be easily inserted into skin to release RONS and slow the decay of RONS thereby prolonging their bioactivity and effectiveness. The new insights into the effective melanoma treatment suggest that the rich mixture of RONS within PA-CMNs prepared by custom-developed hybrid plasma-assisted configuration induces both ferroptosis and apoptosis to selectively kill tumor cells. A significant inhibition of subcutaneous A375 melanoma growth was observed in PA-CMNs-treated tumor-bearing nude mice without any signs of systemic toxicity. The new approach based on PA-CMNs may potentially open new avenues for a broader range of disease treatments.

Off-site production of plasma-activated water for efficient disinfection: The crucial role of high valence NOx and new chemical pathways.

Efficient disinfection of pathogens is a critical concern for environmental disinfection and clinical anti-infective treatment. Plasma-activated water (PAW) is a promising alternative to chemical disinfectants and antibiotics for its strong disinfection ability and not inducing any acute toxicity. Previous plasma sources are commonly placed near or fully in contact with water as possible for more efficient activation, but the risk of electrode corrosion and metal particle contamination of water threatens the safety and stability of PAW. In this work, plasma-activated gas (PAG) rich in high-valence NOx is generated by a hybrid plasma configuration and introduced into water for off-site PAW production. It is found that plasma-generated O3 dominates the gas-phase reactions for the formation of high-valence NOx. With the time-evolution of O3 concentration, the gaseous NO3 radicals are produced behind N2O5 formation, but will be decomposed before N2O5 quenching. By decoupling the roles of gaseous NO3, N2O5, and O3 in the water activation, results show that short-lived aqueous species induced by gaseous NO3 radicals play the most crucial role in PAW disinfection, and the acidic environment induced by N2O5 is also beneficial for microbial inactivation. Moreover, SEM photographs and biomacromolecule leakage assays demonstrate that PAW disrupts the cell membranes of bacteria and thus achieves inactivation. In real-life applications, an integrated device for off-site PAW production with a yield of 2 L/h and a bactericidal efficiency of >99.9 % is developed. The PAW of 50 mL produced in 3 min using this device is more effective in disinfection than 0.5 % NaClO and 3 % H2O2 with the same bacterial contact time. Overall, this work provides new avenues for efficient PAW production and deepens insights into the fundamental chemical processes that govern the reactive chemistry in PAW for environmental and biomedical applications.

Boron-Containing MOF Nanoparticles with Stable Metabolism in U87-MG Cells Combining Microdosimetry To Evaluate Relative Biological Effectiveness of Boron Neutron Capture Therapy.

Accurate prediction of the relative biological effectiveness (RBE) of boron neutron capture therapy (BNCT) is challenging. The therapy is different from other radiotherapy; the dynamic distribution of boron-containing compounds in tumor cells affects the therapeutic outcome considerably and hampers accurate measurement of the neutron-absorbed dose. Herein, we used boron-containing metal-organic framework nanoparticles (BMOFs) with high boron content to target U87-MG cells and maintain the concentration of the 10B isotope in cells. The content of boron in the cells could maintain 90% (60 ppm) within 20 min compared with that at the beginning; therefore, the accurate RBE of BNCT can be acquired. The effects of BNCT upon cells after neutron irradiation were observed, and the neutron-absorbed dose was obtained by Monte Carlo simulations. The RBE of BMOFs was 6.78, which was 4.1-fold higher than that of a small-molecule boron-containing agent (boric acid). The energy spectrum of various particles was analyzed by Monte Carlo simulations, and the RBE was verified theoretically. Our results suggested that the use of nanoparticle-based boron carriers in BNCT may have many advantages and that maintaining a stable boron distribution within cells may significantly improve the efficiency of BNCT.

Efficacy and Safety of Coenzyme Q10 Supplementation in the Treatment of Polycystic Ovary Syndrome: a Systematic Review and Meta-analysis.

The aim of this study is to evaluate the efficacy and safety of coenzyme Q10 supplementation in the treatment of polycystic ovary syndrome (PCOS). We first searched PubMed, Wanfang Data, CNKI, Embase, ClinicalTrial.gov, and other databases. The retrieval time from the establishment of the database to January 2021. We collected relevant randomized controlled trials (RCTs) about coenzyme Q10 in the treatment of PCOS. Risk of bias assessment and meta-analysis of RCTs were performed using RevMan 5.0 software. This systematic review and meta-analysis include a total of 9 RCTs involving 1021 patients. The results show that the addition of coenzyme Q10 may improve insulin resistance (HOMA-IR (WMD - 0.67 [- 0.87, - 0.48], P < 0.00001); fasting insulin (WMD - 1.75 [- 2.65, - 0.84], P = 0.0002); fasting plasma glucose (WMD - 5.20 [- 8.86, - 1.54], P = 0.005)), improve sex hormone levels (FSH (SMD - 0.45 [0.11, 0.78], P = 0.009); testosterone (SMD - 0.28 [- 0.49, - 0.06], P = 0.01)), and improve blood lipids (triglycerides (SMD - 0.49 [- 0.89, - 0.09], P = 0.02); total cholesterol (SMD - 0.35 [- 0.56, - 0.14], P = 0.001); LDL-C (SMD - 0.22 [- 0.43, - 0.01], P = 0.04); HDL-C (SMD 0.22 [0.01, 0.43], P = 0.04)). Only one RCT reported adverse events, and they found that patients had no adverse effects or symptoms following supplementation. Based on the current evidence, it could be considered that the addition of CoQ10 is a safe therapy to improve PCOS by improving insulin resistance (reduce HOMA-IR, FINS, FPG), increasing sex hormone levels (increase FSH, reduce testosterone), and improving blood lipids (reduce TG, TC, LDL-C, and increased HDL-C).

Localized nuclear reaction breaks boron drug capsules loaded with immune adjuvants for cancer immunotherapy.

Boron neutron capture therapy (BNCT) was clinically approved in 2020 and exhibits remarkable tumour rejection in preclinical and clinical studies. It is binary radiotherapy that may selectively deposit two deadly high-energy particles (4He and 7Li) within a cancer cell. As a radiotherapy induced by localized nuclear reaction, few studies have reported its abscopal anti-tumour effect, which has limited its further clinical applications. Here, we engineer a neutron-activated boron capsule that synergizes BNCT and controlled immune adjuvants release to provoke a potent anti-tumour immune response. This study demonstrates that boron neutron capture nuclear reaction forms considerable defects in boron capsule that augments the drug release. The following single-cell sequencing unveils the fact and mechanism that BNCT heats anti-tumour immunity. In female mice tumour models, BNCT and the controlled drug release triggered by localized nuclear reaction causes nearly complete regression of both primary and distant tumour grafts.

A Review of Planned, Ongoing Clinical Studies and Recent Development of BNCT in Mainland of China.

Boron neutron capture therapy (BNCT) is a promising cancer treatment modality that combines targeted boron agents and neutron irradiation to selectively destroy tumor cells. In mainland China, the clinical implementation of BNCT has made certain progress, primarily driven by the development of compact neutron source devices. The availability, ease of operation, and cost-effectiveness offered by these compact neutron sources make BNCT more accessible to cancer treatment centers. Two compact neutron sources, one being miniature reactor-based (IHNI-1) and the other one being accelerator-based (NeuPex), have entered the clinical research phase and are planned for medical device registration. Moreover, several accelerator-based neutron source devices employing different technical routes are currently under construction, further expanding the options for BNCT implementation. In addition, the development of compact neutron sources serves as an experimental platform for advancing the development of new boron agents. Several research teams are actively involved in the development of boron agents. Various types of third-generation boron agents have been tested and studied in vitro and in vivo. Compared to other radiotherapy therapies, BNCT in mainland China still faces specific challenges due to its limited clinical trial data and its technical support in a wide range of professional fields. To facilitate the widespread adoption of BNCT, it is crucial to establish relevant technical standards for neutron devices, boron agents, and treatment protocols.

A Comparison of Epileptogenic Effect of Status Epilepticus Treated With Diazepam, Midazolam, and Pentobarbital in the Mouse Pilocarpine Model of Epilepsy.

Status epilepticus (SE) is a medical emergency associated with acute severe systemic damage and high mortality. Moreover, symptomatic SE is one of the highest risk factors for epileptogenesis. While the antiepileptic drugs (AEDs) are chosen in favor of acute control of SE, the potential short-term and long-term effects of such AEDs have been ignored in clinics. In this study, we hypothesized that AEDs that are used to control acute SE might affect the feasibility for the chronic development of epileptogenesis after SE. Therefore, we sought to compare the epileptogenic effects of SE that are terminated by three AEDs, i.e., diazepam, midazolam, and pentobarbital, which are widely used as first-line anti-SE AEDs. For this purpose, we used a mouse model of SE induced by intraperitoneal (i.p.) injection of lithium chloride (LiCl)-pilocarpine. The pilocarpine-induced SE was terminated with diazepam, midazolam, or pentobarbital. Then we compared short-term and long-term effects of SE with different AED treatments by examining SE-associated mortality and behavioral spontaneous recurrent seizures (SRSs) and by using magnetic resonance imaging (MRI) and immunohistochemistry to evaluate pathological and cellular alterations of mice in the different treatment groups. We found that i.p. injections of diazepam (5 mg/kg), midazolam (10 mg/kg), and pentobarbital (37.5 mg/kg) were able to terminate acute pilocarpine-SE effectively, while pentobarbital treatment showed less neuroprotective action against lethality in the short phase following SE. Long-term evaluation following SE revealed that SE treated with midazolam had resulted in relatively less behavioral SRS, less hippocampal atrophy, and milder neuronal loss and gliosis. Our data revealed an obvious advantage of midazolam vs. diazepam or pentobarbital in protecting the brain from epileptogenesis. Therefore, if midazolam provides as strong action to quench SE as other AEDs in clinics, midazolam should be the first choice of anti-SE AEDs as it provides additional benefits against epileptogenesis.

Boron encapsulated in a liposome can be used for combinational neutron capture therapy.

Boron neutron capture therapy (BNCT) is an attractive approach to treat invasive malignant tumours due to binary heavy-particle irradiation, but its clinical applications have been hindered by boron delivery agents with low in vivo stability, poor biocompatibility, and limited application of combinational modalities. Here, we report boronsome, a carboranyl-phosphatidylcholine based liposome for combinational BNCT and chemotherapy. Theoretical simulations and experimental approaches illustrate high stability of boronsome. Then positron emission tomography (PET) imaging with Cu-64 labelled boronsome reveals high-specific tumour accumulation and long retention with a clear irradiation background. In particular, we show the suppression of tumour growth treated with boronsome with neutron irradiation and therapeutic outcomes are further improved by encapsulation of chemotherapy drugs, especially with PARP1 inhibitors. In sum, boronsome may be an efficient agent for concurrent chemoradiotherapy with theranostic properties against malignancies.

A Boron-10 nitride nanosheet for combinational boron neutron capture therapy and chemotherapy of tumor.

Combination cancer therapy (e.g., radiochemotherapy) is widely used to enhance the therapeutic effects and prevent the recurrence of cancer. However, the side effects of monotherapy are also amplified when treating cancer with combination therapy. A locally activated drug delivery strategy that can release the payload in a tumor-selective manner is greatly needed to overcome the side effects of combination therapy. Here, we explore the potential of combining boron neutron capture therapy and chemotherapy as a new type of radiochemotherapy. Two-dimensional (2D) boron-10-rich nanosheets (BNNSs) were fabricated as a dual-functional delivery system: targeted boron-10 delivery systems for boron neutron capture therapy (BNCT) and drug delivery vehicles to load doxorubicin for chemotherapy. Irradiated by low-energy thermal neutron, BNNSs can produce high linear energy transfer (LET) particles to kill tumor cells, and the loaded doxorubicin can be released in situ at the same time. This neutron-triggered radiochemotherapy shows noteworthy efficacy in suppressing tumor growth in triple-negative breast cancer. To the best of our knowledge, this is the first report to combine BNCT with chemotherapy as a new type of radiochemotherapy. We hope this study could inspire additional BNCT-induced combination cancer therapies and provide insight for the further clinical translation of BNCT.

Covalent Organic Polymer as a Carborane Carrier for Imaging-Facilitated Boron Neutron Capture Therapy.

Boron neutron capture therapy (BNCT) is an atomic targeted radiotherapy that shows fantastic suppression impact on locally intrusive threatening tumors. One key factor for effective BNCT is to aggregate an adequate concentration (>20 ppm) of 10B in the cytoplasm of the tumor. Carborane-loaded polymer nanoparticles are promising because of their outstanding biocompatibility and plasma steadiness. In this study, a new class of carborane-loaded nanoscale covalent organic polymers (BCOPs) was prepared by a Schiff base condensation reaction, and their solubility was greatly improved in common solvents via alkyl chain engineering and size tailoring. The obtained BCOP-5T was further functionalized by biocompatible 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene-glycol)-2000] (DSPE-PEG, molecular weight 2000) to form stable aqueous-phase nanoparticles with a hydrodynamic diameter of around 100 nm. After chelating with radioactive copper-64, DSPE-BCOP-5T was tracked by positron emission tomography (PET) imaging and showed significant accumulation in the tumor. DSPE-BCOP-5T + neutron radiation showed remarkable tumor suppression in 4T1 tumor-bearing mice (murine breast cancer). No obvious physical tissue damage and abnormal behavior were observed, demonstrating that the boron delivery was successful and tumor-selective. To conclude, this study presents a theranostic COP-based platform with a well-defined composition, good biocompatibility, and satisfactory tumor accumulation, which is promising for PET imaging, drug delivery, and BNCT.

Biodistribution studies of boronophenylalanine in different types of skin melanoma.

A study of the 10B-enriched Boronophenylalanine-fructose complex(10BPA-F) infusion procedure in potential BNCT patients, including three skin melanomas of extremities, was performed. 10B concentration in tumor(T), blood(B), skin(S) were measured to determine tumor/blood(T/B) and skin/blood(S/B) ratios. T/B ratio for three melanoma patients was in the range 1.48-3.82(average 2.56 ± 0.69). S/B ratio was in the range 0.81-1.99(average 1.29 ± 0.35). Results showed that T/B ratio of nodular metastasis melanoma was higher than superficial spreading melanoma. 10B concentration in skin was higher than blood, which was helpful to avoid over-dose in normal skin.

On-Demand Biodegradable Boron Nitride Nanoparticles for Treating Triple Negative Breast Cancer with Boron Neutron Capture Therapy.

Compared with photon-induced binary cancer therapy, such as photothermal therapy (PTT) and photodynamic therapy (PDT), boron neutron capture therapy (BNCT) emerges as an alternative noninvasive treatment strategy that could overcome the shallow penetration of light. One key factor in performing successful BNCT is to accumulate a sufficient amount of B-10 (>20 ppm) within tumor cells, which has been a long-standing challenge for small-molecule-based boron drugs. Boron nitride nanoparticles (BNNPs) are promising boron carriers due to their high boron content and good biocompatibility, as certain types of BNNPs can undergo rapid degradation under physiological conditions. To design an on-demand degradable boron carrier, BNNPs were coated by a phase-transitioned lysozyme (PTL) that protects BNNPs from hydrolysis during blood circulation and can be readily removed by vitamin C after neutron capture therapy. According to PET imaging, the coated BNNPs exhibited high tumor boron accumulation while maintaining a good tumor to nontumor ratio. Tail-vein injections of vitamin C were followed by neutron irradiation, and BNNPs were found to be rapidly cleared from major organs according to ex vivo ICP-OES analysis. Compared with the control group, animals treated with BNCT showed suppression of tumor growth, while almost negligible side effect was observed. This strategy not only utilized the high boron content of BNNPs but also successfully performed an on-demand degradation of BNNPs to avoid the potential toxicity caused by the long-term accumulation of nanoparticles.

[The influence of using simplified model for beamlet dose calculations in IMRT treatment planning and the approaches to diminish the influence].

Simplified dose calculation model with high computation efficiency is often used to generate the dose matrices for beamlets in the inverse planning of the intensity modulate radiation therapy. It is likely that this simplification could degrade the quality of the final treatment plans. This paper is aimed at testing the influence of such simplification in dose calculations of beamlets and accordingly proposing methods to avoid severe degradation of the plans. Two simulation instances were adopted. The primary dose calculation model without involvment of scattering effect was used to generate the dose matrices of beamlets. The differential convolution superposition dose calculation model that well accounts for scattering effect was used to calculate the final dose distributions for given intensity profiles. It is found that the simplification in dose matrices of beamlets degrades the dose levels in the edge area of the targets, however, the degradation could be diminished or even avoided by adding a suitable margin around the targets or by using the multiple-shifted-beamlet-matrices (MSBM) method that was proposed in our previous paper.

A realistic appraisal of boron neutron capture therapy as a cancer treatment modality.

Boron neutron capture therapy (BNCT) is a binary therapeutic modality based on the nuclear capture and fission reactions that occur when the stable isotope boron-10 is irradiated with neutrons to produce high-energy alpha particles and recoiling lithium-7 nuclei. In this Commentary we will focus on a number of papers that were presented at a Symposium entitled "Current Clinical Status of Boron Neutron Capture Therapy and Paths to the Future", which was held in September 2017 at the China National Convention Center in Beijing. Results were presented by clinicians from Japan, Finland, the United States, the China mainland and Taiwan, China who have been working in the multiple disciplines that are required for carrying out clinical BNCT. The main focus was on the treatment of patients with malignant brain tumors, recurrent tumors of the head and neck region, and cutaneous melanomas. The results obtained in treating these patients were reported in detail and, although most of the patients with brain tumors and head and neck cancer were not cured, there was evidence of some clinical efficacy. Although there are a number of problems that must be addressed, further clinical studies to evaluate the efficacy of BNCT are warranted. First, despite considerable effort by numerous investigators over the past 40 years, there still are only two boron-containing drugs in clinical use, L-boronophenylalanine (BPA) and sodium borocaptate (BSH). Therefore, until new and more effective boron delivery agents are developed, efforts should be directed to improving the dosing and delivery of BPA and BSH. Second, due to a variety of reasons, nuclear reactor-based BNCT has ended except for its use in the China mainland and Taiwan. Therefore, the future of BNCT depends upon the results of the ongoing Phase II clinical trials that are being carried out in Japan and the soon to be initiated trials that will be carried out in Finland. If the results obtained from these clinical trials are sufficiently promising, then BNCT will have a clear path to the future, especially for patients with the therapeutically challenging malignancies that in the past have been treated with reactor-based BNCT.

Tracing Boron with Fluorescence and Positron Emission Tomography Imaging of Boronated Porphyrin Nanocomplex for Imaging-Guided Boron Neutron Capture Therapy.

Boron neutron capture therapy (BNCT) induces high-energy radiation within cancer cells while avoiding damage to normal cells without uptake of BNCT drugs, which is holding great promise to provide excellent control over locally invasive malignant tumors. However, lack of quantitative imaging technique to determine local boron concentration has been a great challenge for nuclear physicians to apply accurate neutron irradiation during the treatment, which is a key factor that has limited BNCT's application in clinics. To meet this challenge, this study describes coating boronated porphyrins with a biocompatible poly(lactide- co-glycolide)-monomethoxy-poly(polyethylene-glycol) (PLGA-mPEG) micelle for selective tumor accumulation and reduced toxicity comparing with the previously reported boronated porphyrin drugs. Fluorescence imaging and positron emission tomography (PET) imaging were performed, unveiling the potential imaging properties of this boronated porphyrin nanocomplex (BPN) to locate tumor region and to determine tissue-localized boron concentration which facilitates treatment planning. By studying the pharmacokinetics of BPN with Cu-64 PET imaging, the treatment plan was adjusted from single bolus injection to multiple times of injections of smaller doses. As expected, high tumor uptake of boron (125.17 ± 13.54 ppm) was achieved with an extraordinarily high tumor to normal tissue ratio: tumors to liver, muscle, fat, and blood were 3.24 ± 0.22, 61.46 ± 20.26, 31.55 ± 10.30, and 33.85 ± 5.73, respectively. At last, neutron irradiation with BPN showed almost complete tumor suppression, demonstrating that BPN holds a great potential for being an efficient boron delivery agent for imaging-guided BNCT.