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Chemical Imaging Using Ion Microscopy
Published in Arthur T. Hubbard, The Handbook of Surface Imaging and Visualization, 2022
Isabelle Gay, George H. Morrison
Bennett et al.27 have used ion microscopy to study the uptake and localization of boronated drugs in cell cultures as part of boron neutron capture theory (BNCT). BNCT is a cancer treatment in which tumors are destroyed through the combined action of boron-10 and neutrons.29 The tumor cells must be loaded with 10B and subsequently irradiated with a neutron beam. This creates a reaction in which a particles and 7Li nuclei are formed and destroy the cells (10B + n → [11B] → 4He + 7Li + 2.31 MeV). Because of the increased rate of mitosis of malignant cells it is hoped that boronated compounds will selectively taken up by tumor cells. Ideally then these compounds would preferentially localize in the nucleus of the cells where they could irreparably damage the DNA and kill the tumor cells. It is imperative to determine the uptake and intracellular localization of boronated drugs to assess their usefulness as BNCT therapeutic agents. Sensitivity and lateral resolution are critical in this work. Thus, ion microscopy is the method of choice for evaluating the uptake, localization, and quantity of boron in cultured cells. Figure 4.4 shows an ion image of F98 glioma cells treated with the boronated nucleoside CBU-5′. This image shows the clarity and ease of determining boron localization using ion microscopy. In this case the boron concentration was found to be twice as high in the cytoplasm as in the nucleus.30
Neutron Waveguides and Applications
Published in María L. Calvo, Vasudevan Lakshminarayanan, Optical Waveguides, 2018
Ramón F. Alvarez-Estrada, María L. Calvo
BNCT has been applied mostly to malignant brain tumors (gliomas, intra-cerebral melanomas and glioblastomas). In particular, glioblastoma (multiforme) has been one main target for BNCT clinical applications due to poor prognosis of patients after other treatments. In particular, there was some critical assessment by 2001 whether the results of BNCT therapies demonstrated significant benefits for patients compared to other treatments.95 Independent protocols appeared to indicate that BNCT can produce median survival in patients with glioblastoma that appears equivalent to conventional photon therapy. More recent results indicate typical survival of about 23 months for glioblastoma.98 The best survival data for BNCT are at least comparable with those obtained by current standard therapies for patients with multiform glioblastoma.97 A very important aspect is that BNCT treatments appear to give rise to improved quality of life. Head and neck tumors and cutaneous melanomas have also been treated. BNCT has also been applied to multiple liver metastases.92
Dendrimers as Drug and Gene Delivery Systems
Published in Mansoor M. Amiji, Nanotechnology for Cancer Therapy, 2006
Boron neutron capture therapy (BNCT) is a cancer-therapeutic application based on a nuclear capture reaction of a lethal 10B(n, α)7Li3+ reaction.42 If 10B can be delivered at a concentration of at least 109 atoms per cell to tumor tissue, subsequent irradiation with thermal or epithermal neutrons produces highly energetic α particles and Li3+ ions that damage the tumor cells in nuclear fission reaction. To deliver high levels of boron in tumor tissue, it is proposed to use dendrimers as boron carriers for their well-defined molecular structure and multivalency.
Preliminary design study of a simple neutron energy spectrometer using a CsI self-activation method for daily QA of accelerator-based BNCT
Published in Journal of Nuclear Science and Technology, 2019
Ryosuke Kurihara, Akihiro Nohtomi, Genichiro Wakabayashi, Yoshinori Sakurai, Hiroki Tanaka
Boron neutron capture therapy (BNCT) is one of the radiation treatments that utilizes an α particle and a Li nucleus emitted during the nuclear reaction between a 10B and a neutron. Large energy of 2.31 or 2.79 MeV, Q-value of 10B(n, α) 7Li reaction, is locally deposited to a tumor cell. As the range of these high linear energy transfer (LET) particles (about 9 x 10−3 mm and 5 x 10−3 mm in tumor cells for an α particle and a Li nucleus, respectively) is approximately equal to size of tumor cells (typically ~ 10−2 mm), the BNCT has been used to selectively kill tumor cells. This treatment requires intensive neutron sources of which the typical neutron fluence rate is over 109 cm−2 s−1. Recently, instead of conventional nuclear reactor-based neutron sources, accelerator-based neutron sources that can be installed inside hospitals have been developed [1,2].
Boron-incorporating hemagglutinating virus of Japan envelope (HVJ-E) nanomaterial in boron neutron capture therapy
Published in Science and Technology of Advanced Materials, 2019
Shuichiro Yoneoka, Yasuhiro Nakagawa, Koichiro Uto, Kazuma Sakura, Takehiko Tsukahara, Mitsuhiro Ebara
Radiation stimulates cytotoxic T lymphocyte (CTL) activity, and leads to not only systemic antitumor immune response but also growth suppression of nonirradiated metastatic tumors at distant sites from irradiated primary tumor sites. This phenomenon called the abscopal effect has been known to be facilitated by radiotherapy in combination with immunotherapy [17–19]. Recent studies have revealed that the combination of immunotherapy with radiotherapy enables the synergistic enhancement of cancer-treatment efficacy, and global clinical trials for some types of cancer are ongoing [20]. Among the radiation therapy, boron neutron capture therapy (BNCT) is a powerful cancer cell-targeted radiation treatment. The nuclear reaction of thermal neutrons and boron-10 isotopes (10B, 19.9% natural abundance) emits alpha (α) particles and lithium atoms because of the 10B(n,α)7Li reaction. Since the range distance of the particles, ca. 10 µm, is quite close to the size of single cell, the selective destruction of target tumor cells can be accomplished without any effect on normal cells [21]. Low molecular weight boron agents such as sodium borocaptate (BSH) and p-boronophenylalanine (BPA) have been clinically used as boron-containing pharmaceuticals [22,23], while they exhibit a short-term retention time in tumor cells, and often cause vascular endothelial injuries because of the severe increase of boron concentrations in blood [23–29]. Various boron-incorporated macromolecular agents with high boron contents such as liposomes, polymeric nanomicelles, and antibodies have also been produced, and their physiological-pathophysiological evaluation has been performed [30–36]. However, the macromolecular approaches are not satisfactory in terms of the insufficient boron accumulation efficiency in tumor cells, low boron content per unit weight, and the complicated synthesis.