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Basics of Radiation Interactions in Matter
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Although neutrons are generally not directly used in nuclear medicine imaging or therapy applications, it is of interest to know about the properties of these particles because they are essential for the production of radionuclides that are important for daily work, such as 99Mo, which is the mother radionuclide for 99mTc and is produced from fission of 235U.
Medical and Biological Applications of Low Energy Accelerators
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
We shall discuss in some details the particle therapy in Japan where the pioneer work of the particle therapy by cyclotron began at NIRS in 1975. Fast neutrons and protons have been used for cancer treatments. The results for fast neutron therapy were not so excellent and the energy of the proton beam was not enough for the treatment of thick tissue. Higher energy proton therapy begun at the Tsukuba University with proton beams from the 500 MeV booster synchrotron of the 12 GeV KEK proton synchrotron.
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.
Factors affecting the preparation of nanocrystals: characterization, surface modifications and toxicity aspects
Published in Expert Opinion on Drug Delivery, 2023
Shirleen Miriam Marques, Lalit Kumar
Small-angle neutron scattering (SANS) is a method that can be employed to determine structural characteristics at the nanoscale and to investigate modifications taking place in a substance due to various handling and processing techniques as well as changes occurring in-situ [163,164]. Any alterations in the surface structure of crystals could be investigated through fractal dimension parameters and/or the specific surface area. Moreover, for crystalline substances, the data acquired through SANS could be utilized to correlate alterations taking place on the atomic scale, as probed through diffraction, with structural modifications on the nanoscale [163]. Costabile and coworkers performed SANS on nanocrystals conjugated with PEG to deliver a filamenting temperature-sensitive mutant Z protein inhibitor to the lungs. The damaging effects of interaction with mucin were perceptible at a larger scale, i.e. on the nanocrystal size. Concerning the release pattern, the SANS results suggested that the nanocrystals underwent partial dissolution when incubated with mucin [165].
Investigation of radiation protective features of azadispiro derivatives and their genotoxic potential with Ames/Salmonella test system
Published in International Journal of Radiation Biology, 2023
Burak Alaylar, Bünyamin Aygün, Kadir Turhan, Mehmet Karadayı, Esra Cinan, Zuhal Turgut, Gökçe Karadayı, Mohammed Ibrahim Abu Al-Sayyed, Medine Güllüce, Abdulhalik Karabulut
The neutron cross-section is aimed to search the probability of interactions that may occur between the neutron entering a target material and the core of the target material. These interactions usually include elastic and inelastic or nuclear reactions, such as neutron capture, fission, and spallation. Barn (10−28 m2 or 10−24 cm2), which is accepted as the standard unit, is used to indicate this cross-section of interaction. These cross-sections are mostly determined with total macroscopic cross-section and the removal cross-section value is found as follows. The large total or removal cross-section of this cross-section expresses the high probability of interaction that the neutron coming to the material can make with the nucleus of the material (El-Khayatt and El-Sayed Abdo 2009). Any interaction of neutrons with the target material can be defined in different cross-sections as below.
Response of murine neural stem/progenitor cells to gamma-neutron radiation
Published in International Journal of Radiation Biology, 2022
Galina A. Posypanova, Marya G. Ratushnyak, Yuliya P. Semochkina, Alexander N. Strepetov
The aim of this work was to study the sensitivity of cultured murine NSCs/NPCs to the reactor gamma-neutron irradiation (γ,n-irradiation) in a wide dose range (from 25 mGy to 2 Gy) and the features of the formation and repair of DNA DSB in these cells. Neutrons are electrically neutral high-energy particles that produce more severe damage to DNA than photons do; therefore they are more efficient in the therapy of radioresistant tumors. Neutron relative biological effectiveness (RBE) varies from 1 to 10 depending on the kind of tissue, neutron energy, and the parameter explored (Scott and Pandita 2006). The advantage of using fast neutron to eliminate radioresistant cells lies partially in the lesser dependency on cell oxygenation, cell cycle parameters, and proliferation rate (Rockhill and Laramore 2016; Goodhead 2019; Jones 2020). The effective use of neutrons in radiation therapy increases interest in the study of the mechanisms of action of neutron radiation to develop the methods of protection for normal tissues and optimize radiotherapy regimens (Goodhead 2019) since neutron therapy significantly increases the risks of long-term post-radiation complications.