Hiroyuki Miyamaru

Effectiveness of boron neutron capture therapy for recurrent head and neck malignancies.

It is necessary to explore new treatments for recurrent head and neck malignancies (HNM) to avoid severe impairment of oro-facial structures and functions. Boron neutron capture therapy (BNCT) is tumor-cell targeted radiotherapy that has significant superiority over conventional radiotherapies in principle. We have treated with BNCT 42 times for 26 patients (19 squamous cell carcinomas (SCC), 4 salivary gland carcinomas and 3 sarcomas) with a recurrent and far advanced HNM since 2001. Results of (1) (10)B concentration of tumor/normal tissue ratios (T/N ratio) of FBPA-PET studies were SCC: 1.8-5.7, sarcoma: 2.5-4.0, parotid tumor: 2.5-3.7. (2) Therapeutic effects were CR: 12 cases, PR: 10 cases, PD: 3 cases NE (not evaluated): 1 case. Response rate was 85%. (3) Improvement of QOL such as a relief of severe pain, bleeding, and exudates at the local lesion, improvement of PS, disappearance of ulceration, covered with normal skin and preserved oral and maxillofacial functions and tissues. (4) Survival periods after BNCT were 1-72 months (mean: 13.6 months). Six-year survival rate was 24% by Kaplan-Meier analysis. (5) Adverse-events were transient mucositis and alopecia in most of the cases; three osteomyelitis and one brain necrosis were recognized. These results indicate that BNCT represents a new and promising treatment approach for advanced HNM.

Multibody fusion model to explain experimental results

AbstractWorldwide cold fusion experiments have given anomalous results with regard to levels of kilo-electronvolts per atom excess heat, 4He generation, level of emission of neutrons and tritons with a 10−4 to 10−7 neutron-to-triton yield ratio, and emission of high-energy charged particles, which cannot be explained by the known d + d fusion process. A previously proposed multibody deuteron fusion model in solids is elaborated further to explain these anomalous results. A transient dynamics in metal deutendes is proposed to generate close pairs and clusters of deuterons with time-dependent deep atomic potential inducing a strong screening effect on Coulomb barrier penetration. Very approximate numerical estimations of reaction rates for the competing 2D, 3D, and 4D fusion processes in PdDx and TiDx are obtained with high-level reaction rates enough to explain observed heat levels. Decay channels of virtual compound states, i.e., 4He*, 5Li*, 6Li*, 7Be*, and 8Be* by 2D, H + 2D, 3D, H + 3D, and 4D fusions, ...

Ion-induced luminescence of alumina with time-resolved spectroscopy

Ion-induced luminescence of alumina was analyzed with a time-resolved spectroscopic method. By using a pulsed ion beam, we selectively observed the prompt and slow components in the total luminescence. The luminescence spectrum showed some broad peaks at 330 nm (F+ center), 410 nm (F center), 510 nm (F2 center), 560 nm (F2+ 2 center). By observing prompt luminescence in detail, new emission bands have been identified in the wavelength range from 400 to 450 nm. Furthermore, the lifetime of each luminescence was successfully evaluated with single photon counting. The emission band at 400 nm was found to have a short lifetime of 1.9 ns. From the analysis of a slow luminescence component, it was observed that the emission band with a long lifetime appeared around the wavelength of 330 nm.

Ion-induced luminescence of silica glasses

Abstract We have performed in situ analysis of ion-induced luminescence of silica glasses in terms of incident ion energy and fluence, to investigate the origin of the luminescence and the influence of implanted deuterium and helium ions. The luminescence spectra of SiO 2 glasses induced by D + and He + irradiation showed a broad band centered at around 450 nm. By comparing with TRIM calculations, we can conclude that the luminescence is caused by electron excitation effects of implanted ions. In the early stage of the irradiation, most of the luminescence comes from intrinsic defect centers. With increasing ion fluence, the luminescence intensity increased, taking maximum and then decreased. This indicates that the first increase is attributed to the increase of newly produced defect centers by atomic displacements, while the decrease is probably owing to the growth and clustering of the defects and/or precipitation of Si clusters. When the fluence is translated to dpa, changes of the luminescence intensity between D + irradiation and He + are very similar. This result also supports that the additional luminescence centers are produced by atomic displacements. The luminescence centers are very likely oxygen vacancy or oxygen deficiency related ones but OH has some role.

Development of a thick CdTe detector for BNCT–SPECT

As well known, it is difficult to know the exact treatment effect of boron neutron capture therapy (BNCT). It depends on the irradiation time, which is changed rather flexibly. At present, it is once fixed before BNCT. Then the actual stopping time is adjusted during BNCT by some means like activation foils. The authors group hence started development of a single-photon emission computed tomography (SPECT) system for BNCT to know the effect of BNCT in real time. By adopting a side surface (1×2 mm(2)) of a CdTe detector (1×2×20 mm(3)) as radiation entrance window, acceptable spatial resolution and high detection efficiency were simultaneously achieved. Also in about 30 min acceptable number of counts for 478 keV gamma-rays could be expected. In addition, employing a Schottky type detector the energy resolution could be improved. Discrimination of 478 keV and annihilation gamma-rays would thus be successfully made. In the next phase, it is planned to design and develop an array type detector to be implemented in the BNCT-SPECT system.

Measurement and Analysis of Neutron-Induced Alpha Particle Emission Double-Differential Cross Section of Carbon at 14.2 MeV

We carried out a detailed measurement of the neutron-induced α-particle emission double-differential cross section of carbon at 14.2MeV, for which there are few measured data in spite of its importance in many applications. In our measurement, a superior S/N ratio, high angular/energy resolutions and a wide detection energy range were realized with a pencil DT neutron beam and a countertelescope system. The obtained cross section for the 12C(n,α0)9Be(ground state) reaction agreed well with the results of previous experiments and evaluated nuclear data. The obtained angular-differential cross section of the 12C(n,n′+3α) reaction for α-particles showed a strong forward-peaked distribution that suggested a significant contribution of the direct reaction process to the 3α breakup. We attempted to calculate the emitted particle spectra by a Monte Carlo method and estimate the branching ratio of the channels that contribute to the 12C(n,n′+3α) reaction. As a result, it was found that the 12C(n,α)9Be* channels play an important role in generating the experimental double-differential cross section both of emitted α-particles and neutrons. The estimated ratio of the 12C(n,α)9Be* channels was approximately 40%, somewhat larger than those evaluated in previous studies.

Anomalous enhancement of three-body deuteron fusion in titanium-deuteride with low-energy D+ beam implantation

Anomalous enhancement of three-body deuteron fusion reactions was observed by low-energy D + ion beam implantation experiment with titanium-deuteride (TiD x : x = 1.4) using a ΔE-E charged-particle spectrometer. The enhancement ratio was ∼10 26 , compared with the traditional theory estimation for a beam/target interaction of the random nuclear reaction process. Two characteristic charged particles of 4.75-MeV helium ( 3 He) and 4.75-MeV triton from the reaction channel of 3D → t + 3 He + 9.5 MeVwere identified by the analysis of measured one- and two-dimensional spectral data. An experimentally obtained 3D fusion rate was on the order of 10 2 fusion/s, which is a surprisingly large value. Strong enhancement of 4D fusion was also indicated by higher-energy alpha-particle spectra. A possible explanation is given by the hypothesis of simultaneous multibody fusion induced with the coherent dynamic motion of three to four deuterons and many electrons around special focal points in a metal-deuteride lattice. The observed enormous enhancement of the 3D fusion rate suggests the possibility of nuclear fusion in solid at room temperature, i.e., so-called cold fusion, which may open a new physics field between nuclear physics and solid-state physics.

Detection of three-body deuteron fusion in titanium deuteride under the stimulation by a deuteron beam

Abstract Two unique particles with equal energy (4.75 MeV triton and 4.75 MeV helium-3) created by three-body deuteron fusion (3D fusion) reactions were for the first time clearly observed from a highly D-loaded TiDx sample under stimulation by a low-energy deuteron beam. The ratio of reaction rate to 2D fusion was [3D]/[2D]=10−4, while estimation by the established theory of nuclear fusion in random (free particle) reaction processes gives [3D]/[2D]=10−30 and fails to explain the experiment. To explain the observed enormous enhancement of 3D fusion, coherent fusion processes in dynamics of a metal–deuteride lattice should be considered.

Characterization measurement of a thick CdTe detector for BNCT-SPECT - detection efficiency and energy resolution.

Author׳s group is carrying out development of BNCT-SPECT with CdTe device, which monitors the therapy effect of BNCT in real-time. From the design calculations, the dimensions were fixed to 1.5×2×30mm(3). For the collimator it was confirmed that it would have a good spatial resolution and simultaneously the number of counts would be acceptably large. After producing the CdTe crystal, the characterization measurement was carried out. For the detection efficiency an excellent agreement between calculation and measurement was obtained. Also, the detector has a very good energy resolution so that gamma-rays of 478keV and 511keV could be distinguished in the spectrum.

Replication Of MHI Transmutation Experiment By D2 Gas Permeation Through Pd Complex

We performed D-permeation experiments similar to the MHI’s experiment 1 three times, and we confirmed the production of Pr. Pd complex samples were provided to us by MHI. The surface was electrolytically cleaned to remove hydrocarbons before depositing Cs. D2 gas was permeated through the Pd complexes at 343 K and 1 atm for about 5 days. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was performed to analyze the existence of the elements (Cs and Pr) and the mass distribution. The results showed the existence of Pr. And we also confirmed the existence of Pr by using fast Neutron Activation Analysis (NAA) in Fusion Neutronics Source (FNS) of Japan Atomic Energy Research Institute (JAERI). As a result, we confirmed that the nuclear transmutation reaction, from 133 Cs to 141 Pr, was occurred. This transmutation suggests that the mass numbers and atomic numbers increase 8 and 4, respectively. The model of multi-body resonance fusion of deuterons proposed by A. Takahashi 2 can explain this mass-8-and-charge-4 increased transmutation.