Treatment planning for the layer-stacking irradiation system for three-dimensional conformal heavy-ion radiotherapy

We have upgraded a heavy-ion radiotherapy treatment-planning system to adapt for the layer-stacking irradiation method, which is to conform a variable spread-out Bragg peak to a target volume by means of dynamic control of the conventional beam-modifying devices. The biophysical model, the beam-setup logic, and the dose-calculation algorithm implemented for the layer-stacking method are described and the expected clinical usability is discussed. The layer-stacking method was integrated in perfect accordance with the ongoing conventional treatments so that the established protocols, which are the clinically optimized dose fractionation schemes, will still be valid. On the other hand, a simulation study indicated a substantial improvement of dose distribution with the layer-stacking method though the significance may depend on the size, shape, and location of the tumor. The completed treatment system will provide an option for improved conformal radiotherapy without interfering with the conventional method and we expect a gradual expansion of the clinical cases applicable to the layer-stacking method

シガケン ナガハマシ ホウゲン ノ ソザイ タイグウ ケイシキ ニ カンスル キジュツテキ ケンキュウ

The isomerization of n-hexadecane over Pt–WO3 catalysts supported on TiO2–SiO2 synthesized by glycothermal reaction with various Si/Ti molar ratios was examined. The catalyst performance depended on Si/Ti molar ratio and WO3 loading. The characterization of the catalysts by XRD, XAFS, UV-vis and so on revealed that with increasing the WO3 loading, the structure of surface W species changed from monomeric species to polytungstate species, which is considered to significantly affect the isomerization selectivity of the catalysts

Impact of neoadjuvant intensity-modulated radiation therapy on borderline resectable pancreatic cancer with arterial abutment; a prospective, open-label, phase II study in a single institution

BACKGROUND: Borderline resectable pancreatic cancer (BRPC) is a category of pancreatic cancer that is anatomically widely spread, and curative resection is uncommon with upfront surgery. Intensity-modulated radiation therapy (IMRT) is a form of radiation therapy that delivers precise radiation to a tumor while minimizing the dose to surrounding normal tissues. Here, we conducted a phase 2 study to estimate the curability and efficacy of neoadjuvant chemoradiotherapy using IMRT (NACIMRT) for patients with BRPC with arterial abutment (BRPC-A). METHODS: A total of 49 BRPC-A patients were enrolled in this study and were treated at our hospital according to the study protocol between June 2013 and March 2021. The primary endpoint was microscopically margin-negative resection (R0) rates and we subsequently analyzed safety, histological effect of the treatment as well as survivals among patients with NACIMRT. RESULTS: Twenty-nine patients (59.2%) received pancreatectomy after NACIMRT. The R0 rate in resection patients was 93.1% and that in the whole cohort was 55.1%. No mortality was encountered. Local therapeutic effects as assessed by Evans classification showed good therapeutic effect (Grade 1, 3.4%; Grade 2a, 31.0%; Grade 2b, 48.3%; Grade 3, 3.4%; Grade 4, 3.4%). Median disease-free survival was 15.5 months. Median overall survival in the whole cohort was 35.1 months. The only independent prognostic pre-NACIMRT factor identified was serum carbohydrate antigen 19-9 (CA19-9) > 400 U/ml before NACIMRT. CONCLUSIONS: NACIMRT showed preferable outcome without significant operative morbidity for BRPC-A patients. NACIMRT contributes to good local tumor control, but a high initial serum CA19-9 implies poor prognosis even after neoadjuvant treatment. TRIAL REGISTRATION: UMIN-CTR Clinical Trial: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000011776 Registration number: UMIN000010113. Date of first registration: 01/03/2013

鉄-スズ系複合酸化物のガスセンサ性能と局所構造(B. 生活科学)

The Fe K-edge X-ray absorption spectra have been recorded to study local structures around iron for fine powdery α-Fe_2O_3-SnO_2 gas sensor which was prepared by the thermal decomposition of coprecipitates from aqueous ferric sulfate and stannic chloride solutions at pH 8. Tin atoms are substituted for iron atoms in the corundum structure of α-Fe_2O_3 below 15 mo 1% of SnO_2 which is the limit of dissolution. Further addition of SnO_2 brings about the system unstable by that SnO_2 enters the lattice as a substitutional defect and produces tetrahedral iron oxide species. The high sensor sensitivity for CH_4 is intimately correlated with the amount of dissolved SnO_2 into α-Fe_2O_3

Effect of Mn content on physical properties of CeOx–MnOy support and BaO–CeOx–MnOy catalysts for direct NO decomposition

A series of manganese–cerium mixed oxides were prepared by a glycothermal method, and the NO decomposition activities of the Ba-loaded Ce–Mn oxides were examined. Among the catalysts examined, the highest NO conversion was obtained on the BaO/Ce–Mn oxide catalyst with a Mn/(Ce+Mn) ratio of 0.25. The X-ray diffraction and Raman analyses indicated the formation of Ce–Mn oxide solid solutions with a cubic fluorite structure. The electron spin resonance analysis indicated the presence of paramagnetic Mn2+ species in the composite catalysts. Incorporation of Mn2+ in the fluorite structure of CeO2 causes an increase in the concentration of oxygen vacancies, which play an important role in the NO decomposition activity of the catalysts. The catalysts were also characterized by X-ray photoelectron spectroscopy and temperature-programmed reduction techniques. Based on the results obtained, the relationship between the physical properties of the catalysts and their NO decomposition activities was discussed