Purpose: In boron-10 neutron capture enhancement of fast neutron irradiation (BNCEFN), the dose enhancement is correlated to the 10B concentration and thermal neutron flux. A new irradiation technique is presented to optimize the thermal neutron flux.
Methods And Materials: The coupled FLUKA and MCNP-4A Monte Carlo codes were used to simulate the neutron production and transport for the Nice and Orleans facilities.
Results: The new irradiation technique consists of a 20-cm lead blocks additional collimator, placed close to the patient's head, which is embedded in a pure graphite cube. A 24-fold thermal neutron flux increase is calculated between a 5 x 5 cm2 primary collimated field, with the patient's head in the air, and the same field size irradiated with the optimum irradiation technique. This increase is more important for the p(60)+Be Nice beam than for the p(34)+Be Orleans one. The thermal neutron flux is 2.1 x 10(10) n(th)/Gy for each facility. Assuming a 100 microg/g 10B concentration, a physical dose enhancement of 22% is calculated. Moreover, the thermal neutron flux becomes independent of the field size and the phantom head size.
Conclusion: This technique allows conformal irradiation of the tumor bed, while the thermal neutron flux is enhanced, and spreads far around the tumor.
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http://dx.doi.org/10.1016/s0360-3016(98)00478-7 | DOI Listing |
Materials (Basel)
January 2025
Institut Laue-Langevin (ILL), 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France.
Intense sources of very cold neutrons (VCNs) would be beneficial for various neutron scattering techniques and low-energy particle physics experiments. Binary clathrate hydrates hosting deuterated tetrahydrofuran (THF-d) and dioxygen show promise as potential moderators for such sources due to a rich spectrum of localized low-energy excitations of the encaged guest molecules. In this article, we present a reliable manufacturing technique for such hydrates.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Mechanical and Industrial Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA.
To push upper boundaries of thermal conductivity in polymer composites, understanding of thermal transport mechanisms is crucial. Despite extensive simulations, systematic experimental investigation on thermal transport in polymer composites is limited. To better understand thermal transport processes, we design polymer composites with perfect fillers (graphite) and defective fillers (graphite oxide), using polyvinyl alcohol (PVA) as a matrix model.
View Article and Find Full Text PDFJ Low Temp Phys
December 2024
Physik-Department, Technische Universität München, Garching, Germany.
Any experiment aiming to measure rare events, like Coherent Elastic neutrino-Nucleus Scattering (CE NS) or hypothetical Dark Matter scattering, via nuclear recoils in cryogenic detectors relies crucially on a precise detector calibration at sub-keV energies. The Crab collaboration developed a new calibration technique based on the capture of thermal neutrons inside the target crystal. Together with the Nucleus experiment, first measurements with a moderated Cf neutron source and a cryogenic detector were taken.
View Article and Find Full Text PDFAppl Radiat Isot
January 2025
Department of Molecular and Genomic Biomedicine, Nagasaki University Graduate School of Biomedical Sciences, 852-8523, Nagasaki, Japan; Central Radioisotope Division, National Cancer Center Research Institute, 104-0045, Tokyo, Japan; Division of BNCT, EPOC, National Cancer Center, Tokyo, Japan; Division of Chemotherapy and Clinical Cancer Research, National Cancer Center Research Institute, 104-0045, Tokyo, Japan. Electronic address:
Boron neutron capture therapy (BNCT) is based on nuclear reactions between thermal neutron and boron-10 preferentially distributed in the cancer cells. B-boronophenylalanine (BPA) is the approved drug for treatment of oral cancers for BNCT. However, the predictive biomarkers to evaluate therapeutic efficacy and side-effects have not been clarified yet.
View Article and Find Full Text PDFSci Rep
January 2025
Radiation Biophysics and Radiobiology Laboratory, Physics Department, University of Pavia, Pavia, Italy.
We present new developments for an ab-initio model of the neutron relative biological effectiveness (RBE) in inducing specific classes of DNA damage. RBE is evaluated as a function of the incident neutron energy and of the depth inside a human-sized reference spherical phantom. The adopted mechanistic approach traces neutron RBE back to its origin, i.
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