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Simple Summary: Boron neutron capture therapy (BNCT) is a tumor-selective particle radiotherapy. It combines preferential boron accumulation in tumors and neutron irradiation. Throughout the history of BNCT, huge efforts have been made on the development of more efficient boron-carrying agents. We analyzed, in this review, those articles published between 2020 and 2023 reporting new boron compounds and strategies that were proved therapeutically useful in in vitro and/or in vivo radiobiological studies, a critical step for translation to a clinical setting. We also explored new pathologies that could potentially be treated with BNCT. We analyzed examples of newly studied theranostic boron agents that could improve significantly BNCT therapeutic effect. These radiobiological advances intend to solve those limitations and questions that arise during patient treatment in the clinical field, with BNCT and other therapies. An active communication between clinicians, radiobiologists, and all disciplines will improve BNCT for cancer patients, in a cost- and time-effective way. Boron neutron capture therapy (BNCT) is a tumor-selective particle radiotherapy. It combines preferential boron accumulation in tumors and neutron irradiation. The recent initiation of BNCT clinical trials employing hospital-based accelerators rather than nuclear reactors as the neutron source will conceivably pave the way for new and more numerous clinical trials, leading up to much-needed randomized trials. In this context, it would be interesting to consider the implementation of new boron compounds and strategies that will significantly optimize BNCT. With this aim in mind, we analyzed, in this review, those articles published between 2020 and 2023 reporting new boron compounds and strategies that were proved therapeutically useful in in vitro and/or in vivo radiobiological studies, a critical step for translation to a clinical setting. We also explored new pathologies that could potentially be treated with BNCT and newly developed theranostic boron agents. All these radiobiological advances intend to solve those limitations and questions that arise during patient treatment in the clinical field, with BNCT and other therapies. In this sense, active communication between clinicians, radiobiologists, and all disciplines will improve BNCT for cancer patients, in a cost- and time-effective way. [ABSTRACT FROM AUTHOR]

The aim. To conduct an analytical literature review on the possible impact of SARS-CoV-2 on the radiosensitivity of the human body and justify the relevance of radiobiological research in this area. Materials and methods. Analysis of data from biological dosimetry / indication of radiation lesions of human peripheral blood T-lymphocyte chromosomes under medical irradiation for comparison with radiosensitivity in the patients recovered from COVID-19 (Scopus International Scientific Metric Database, IAEA guidelines, 2011). Results. With the ongoing COVID-19 pandemic, forecasting and clarifying of the mechanisms of distant effects resulting from interactions between ionizing radiation and the SARS-CoV-2 virus play an important role. The difficulty in solving this problem is caused by the fact that the global science has no exhaustive information on the possible influence of this virus on radiation-induced effects. The attention of the professional community is drawn to the possible impact of SARS-CoV-2 on the radiosensitivity of the body of patients recovered from COVID-19 and a hypothesis is first proposed regarding the mechanism on how to increase it based on the development of systemic long-term inflammation. Therefore, clinical trials of low-dose radiotherapy for the treatment of COVID-19-related pneumonia involve preliminary radiobiological studies to answer the following question: does the SARS-CoV-2 virus affect the radiosensitivity of the human body? Long-term experience of the author of this paper in biodosimetric (cytogenetic) studies allows her to recommend the peripheral blood lymphocyte test system with chromosome aberration's analysis as the most radiosensitive cell model. Conclusions. Clinical trials of low-dose radiotherapy for the treatment of COVID-19 pneumonia involve a preliminary radiobiological study to answer the following question: does the SARS-CoV-2 virus affect the radiosensitivity of the human body? The most optimal approach for the solution of this problem is the use of test-system of human peripheral blood lymphocytes' culture with the subsequent cytogenetic analysis. It will allow investigating changes in the "doseeffect" "cell cycle stage-effect" dependencies, as well as changes in individual radiosensitivity under the influence of SARS-CoV-2 virus [ABSTRACT FROM AUTHOR]

Boron neutron capture therapy (BNCT) is a tumour selective particle radiotherapy, based on the administration of boron carriers incorporated preferentially by tumour cells, followed by irradiation with a thermal or epithermal neutron beam. BNCT clinical results to date show therapeutic efficacy, associated with an improvement in patient quality of life and prolonged survival. Translational research in adequate experimental models is necessary to optimise BNCT for different pathologies. This review recapitulates some examples of BNCT radiobiological studies for different pathologies and clinical scenarios, strategies to optimise boron targeting, enhance BNCT therapeutic effect and minimise radiotoxicity. It also describes the radiobiological mechanisms induced by BNCT, and the importance of the detection of biomarkers to monitor and predict the therapeutic efficacy and toxicity of BNCT alone or combined with other strategies. Besides, there is a brief comment on the introduction of accelerator-based neutron sources in BNCT. These sources would expand the clinical BNCT services to more patients, and would help to make BNCT a standard treatment modality for various types of cancer. Radiobiological BNCT studies have been of utmost importance to make progress in BNCT, being essential to design novel, safe and effective clinical BNCT protocols. [ABSTRACT FROM AUTHOR]

FLASH-radiotherapy (FLASH-RT) is an emerging modality that uses ultra-high dose rates of radiation to enable curative doses to the tumor while preserving normal tissue. The biological studies showed the potential of FLASH-RT to revolutionize radiotherapy cancer treatments. However, the complex biological basis of FLASH-RT is not fully known yet. Within this context, our aim is to get deeper insights into the biomolecular mechanisms underlying FLASH-RT through Fourier Transform Infrared Microspectroscopy (FTIRM). C57Bl/6J female mice were whole brain irradiated at 10 Gy with the eRT6-Oriatron system. 10 Gy FLASH-RT was delivered in 1 pulse of 1. 8 μ s and conventional irradiations at 0.1 Gy/s. Brains were sampled and prepared for analysis 24 h post-RT. FTIRM was performed at the MIRAS beamline of ALBA Synchrotron. Infrared raster scanning maps of the whole mice brain sections were collected for each sample condition. Hyperspectral imaging and Principal Component Analysis (PCA) were performed in several regions of the brain. PCA results evidenced a clear separation between conventional and FLASH irradiations in the 1800–950 cm−1 region, with a significant overlap between FLASH and Control groups. An analysis of the loading plots revealed that most of the variance accounting for the separation between groups was associated to modifications in the protein backbone (Amide I). This protein degradation and/or conformational rearrangement was concomitant with nucleic acid fragmentation/condensation. Cluster separation between FLASH and conventional groups was also present in the 3000–2800 cm−1 region, being correlated with changes in the methylene and methyl group concentrations and in the lipid chain length. Specific vibrational features were detected as a function of the brain region. This work provided new insights into the biomolecular effects involved in FLASH-RT through FTIRM. Our results showed that beyond nucleic acid investigations, one should take into account other dose-rate responsive molecules such as proteins, as they might be key to understand FLASH effect. • This study explores the capabilities of FTIRM to investigate FLASH-RT • FTIRM allowed to rebuild the action of FLASH-RT on normal brain at 24 h • FLASH-RT induces differences in protein signature compared to conventional dose-rates • FLASH-RT induces reduced nucleic acid damage compared to conventional irradiations • Dose-rate responsive molecules such as proteins might be key to understand FLASH-RT [ABSTRACT FROM AUTHOR]

Translational research in adequate experimental models is necessary to optimize boron neutron capture therapy (BNCT) for different pathologies. Multiple radiobiological in vivo studies have been performed in a wide variety of animal models, studying multiple boron compounds, routes of compound administration, and a range of administration strategies. Animal models are useful for the study of the stability and potential toxicity of new boron compounds or delivery systems, BNCT theranostic strategies, the evaluation of biomarkers to monitor BNCT therapeutic and adverse effects, and to study the BNCT immune response by the host against tumor cells. This article will mention examples of these studies, highlighting the importance of experimental animal models for the advancement of BNCT. Animal models are essential to design novel, safe, and effective clinical BNCT protocols for existing or new targets for BNCT.