In order to investigate the behavior and distribution of metallic elements including rare earth elements(REEs), thorium(Th) and uranium(U) in the agricultural field, these elements in agricultural soils were partitioned into 6 fractions by a sequential extraction procedure:water soluble(F1), exchangeable(F2), bound to inorganic matter(F3), bound to organic matter(F4), bound to free oxides(F5) and residual(F6) fractions, and determined for each fraction as well as for total amount. Soil samples were collected from the agricultural field (paddy and upland field) and non-agricultural field in Sakata City (from 2005 to 2010) and Murayama City (from 2008 to 2010) in Yamagata Prefecture, and Sekikawa Village, Iwafune District(from 2007 to 2010) in Niigata Prefecture. Consequently, the following matters have been mainly clarified. (1) The distribution proportion of metallic elements among six fractions of the soils are varied depending on elements and soil utilization(i.e., paddy, upland or no plow). Among REEs, the tendency that the proportion of F5 of heavy-REE(HREE) is generally larger than that of light-REE(LREE) or in middle-REE(MREE) can be found. (2) The differences of REEs concentrations(or REE pattern) of soils are observed among sampling points. It can be related to the nature of soil including the content of Fe-Mn oxides or organic carbon(i.e., the affinity for free oxides or organic matter). (3) The distribution proportion as well as total concentrations of metallic elements in soils are not greatly varied regardless of sampling period(i.e., spring or autumn).
The state of Fe in epidote from Osayama area, Niimi City, Okayama Prefecture, Japan, was investigated by Mössbauer spectroscopy. Chemical composition analyses by EPMA proved that chemical composition of sample was Ca2.2(Al2.4, Fe0.4)2.8Si3.0O12.0(OH)1.0. Single crystal X-ray analysis showed that the sample has a typical epidote structure(P21/m). From the Mössbauer spectrum of the sample, chemical state of Fe in lattice splits into 3 states, two being Fe3+, and one Fe2+. Analysis of the spectrum also suggested that the octahedral Fe3+ into two sites, M3 and M3', and that Fe is not distributed in M1 site. The result suggests that the paleotemperature of rock belt containing the sample is about 200°C.
The massive earthquake that occurred in northeastern Japan on March 11, 2011 triggered a severe nuclear accident at Fukushima Daiich Nuclear Power Station. Since the accident, concentrations of radionuclides in airborne dust, foodstuffs and drinking water, and &gannma;-ray dose rate have been monitored at Fukazawa, Setagaya-ku in Tokyo. Based on the results obtained until May 31, we tried to calculate internally exposed dose due to 132Te, 131I, 132I, 134Cs and 137Cs, and externally exposed dose calculated from air dose rates. Cumulative dose in one year from the day when we started monitoring was estimated to be 425.1μSv, which does not exceed 1mSv, the annual dose limit of public given by ICRP.
There are several guidelines for PET performance evaluation. Most of them require a lot of time and strict conditioning. Here we selected 5 items from the guidelines with some adjustments on which we evaluate and compare PET performances of seven facilities for the purpose of clarifying why and how PET quantitative values are different among facilities. The results show that the data vary even with the same type of PET machine when the image reconstruction method is different. This suggests that the terms of data reconstruction have to be considered as well as the difference of PET performance when we refer PET data of other facilities for clinical purpose.
The involvement with the forefront of the radiation therapy by medical physicists, and the education of the medical physics in the undergraduate and the graduate course are becoming established at last. A role of the medical physics in the radiology is increased while team medical care is demanded, and the innovative activity of medical physics is greatly expected.