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Medical and Biological Applications of Low Energy Accelerators
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
It is likely that, unless dramatic progress is made in cancer prevention or cure, radiotherapy (i.e., the selective destruction of cancer tissues by the use of ionizing radiations) will remain one of the pillars in cancer therapy. The most common irradiation facilities in hospitals nowadays are still 60Co sources and electron accelerators (e.g., Japan has more than 620 linear electron accelerators devoted to medical applications). However, among the possible radiations usable in radiotherapy (X-rays, γ-rays, electrons, protons, heavy ions, π-mesons and neutrons) it is generally agreed that high-energy protons exhibit the best ballistic specificity, i.e., the best ratio of the dose delivered into the tumor, compared to the dose delivered to neighboring tissues. Particle therapy is being applied at more than twenty locations around the globe. Neutron therapy has also been performed for many years and the new hope is with boron neutron capture therapy (BNCT) in which a tumor is loaded with a boron-dope compound and then irradiated by epithermal neutrons.
Introduction to Cancer
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
Neutrons (which are particles rather than γ- or X-rays) are also used in cancer therapy (see Chapter 10). For example, a process known as high linear energy transfer has been developed to kill hypoxic cells by irradiating the tumor with neutrons that then decay to α-particles, the latter causing cellular damage in an oxygen-independent manner. A more sophisticated treatment known as boron neutron capture therapy involves administration of a boron-10 (10B)–enriched delivery agent that is taken up selectively by the tumor. The target area is then irradiated with low energy neutrons that are captured by the 10B atoms, thus leading to a reaction that produces α–particles (4He) and lithium-7 (7Li) ions that destroy the tumor tissue.
Area and Individual Radiation Monitoring
Published in Arash Darafsheh, Radiation Therapy Dosimetry: A Practical Handbook, 2021
Neutron monitoring techniques inside treatment rooms have been described in the literature [27, 28]; and are not discussed in this chapter. Only, neutron monitoring outside shielded rooms and accelerators are discussed. Radiotherapy facilities requiring external neutron monitoring include therapy linacs, fast neutron therapy, BNCT and particle therapy facilities.
Accelerator-based boron neutron capture therapy for malignant glioma: a pilot neutron irradiation study using boron phenylalanine, sodium borocaptate and liposomal borocaptate with a heterotopic U87 glioblastoma model in SCID mice
Published in International Journal of Radiation Biology, 2020
Evgenii Zavjalov, Alexander Zaboronok, Vladimir Kanygin, Anna Kasatova, Aleksandr Kichigin, Rinat Mukhamadiyarov, Ivan Razumov, Tatiana Sycheva, Bryan J. Mathis, Sakura Eri B. Maezono, Akira Matsumura, Sergey Taskaev
To combat this resistance, boron neutron capture therapy (BNCT) is a promising direction in the treatment of brain tumors. It was designed to be binary, first proposed by Locher (1936), and it is based on the interaction of two relatively harmless components: a 10B-nucleus and a thermal neutron. Selective accumulation of 10B inside tumor cells and subsequent irradiation with epithermal neutrons results in destruction of only tumor cells. At the same time, surrounding healthy cells are not exposed to the damaging effects of radiation mainly due to lesser boron accumulation (Locher 1936). Clinical trials conducted at nuclear reactors showed the efficacy of BNCT in treatment of brain tumors, including glioblastomas, as well as in soft tissue tumors, tumors of parenchymal organs and skin cancer (Iarullina et al. 2015; Barth et al. 2018).
Research progress on therapeutic targeting of quiescent cancer cells
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Jinhua Zhang, Jing Si, Lu Gan, Cuixia Di, Yi Xie, Chao Sun, Hongyan Li, Menghuan Guo, Hong Zhang
Boron neutron capture therapy (BNCT) is a novel targeted radiotherapy that selectively kills tumor cells. After introduction into the human body, Boron (10B) is enriched in tumor cells and reacts with neutrons. The reaction generates high LET α particles (4He) and recoiling 7Li nuclei, which result in the induction of DSBs with strong biological effectiveness. Since the path lengths of these particles are almost equal to cell diameter size, only 10B-containing cancer cells are theoretically destroyed without causing serious radiation injury to surrounding normal tissue [92,93]. The cellular distribution of 10B from L-para-boronophenylalanine-10B (BPA) is believed to be largely dependent on the capability of the cells to take up 10B whereas that from sodium mercaptoundecahydrododecaborate-10B (BSH) mainly relies on drug diffusion [11]. Importantly, the use of a 10B-carrier in BNCT, especially BPA, not only effectively eliminates hypoxia and quiescent cells but also kills oxygenated and proliferative cells [11,94].
Effects of boron-containing compounds on immune responses: review and patenting trends
Published in Expert Opinion on Therapeutic Patents, 2019
Karla S. Romero-Aguilar, Ivonne M. Arciniega-Martínez, Eunice D. Farfán-García, Rafael Campos-Rodríguez, Aldo A. Reséndiz-Albor, Marvin A. Soriano-Ursúa
Different reports have shown that boric acid administration induces changes in anatomical barriers. Accordingly, repair of skin, respiratory and gastrointestinal epithelia is often reported after administration of boric acid (1) (chemical structures for BCCs are shown in Figure 1) [17,18]. Effects on ocular membranes and tears have also been reported, and boric acid (1) is often used as an antiseptic and buffering agent in eye solutions [19]. Conversely, some reports have suggested that boric acid can disrupt blood-brain barrier permeability, though evidence of such a mechanism has not been demonstrated [20,21]. There are fewer data for other BCCs, such as 2-aminoethoxydiphenyl borate (2APB (2)) or borax (3), which alleviate rhinitis, likely through action on epithelia [22]. Some agents used in boron neutron capture therapy (BNCT) induce skin or mucous membrane damage to different grades after irradiation, which is attractive for the development of therapeutic tools for some types of cancer [23,24]. Additionally, some changes in tears have been reported in mammals [25], but less evidence exists regarding effects on the volume or composition of other secretions such as milk [26].