We present a quantitative imaging of 28Mg in Arabidopsis using real‐time RI imaging system(RRIS). First, performance of RRIS in quantitative determination was characterized using standard spots. The results showed that the dynamic range for 28Mg determination was three orders of magnitude. Next, quantitative accuracy of measurement was studied for a variety of pant tissues of Arabidopsis. The detection of the β‐rays emitted from 28Mg and its daughter radionuclide, 28Al, was found to be slightly affected by the self‐absorption by the plant tissue. Nevertheless, the degree of the self‐absorption could be determined by the tissue type, indicating that the RRIS can be applied to the quantitative and time‐course analysis of the 28Mg in each tissue type. The 28Mg transport amount in the Arabidopsis shoot tissue was analyzed using the system. It was found that the activity of Mg unloading from vascular tissue was higher in the young stem compared to the old stem.
The in-vivo monitoring method used for assessment of internal exposure is outlined. An in-vivo counter consists of a detection assembly, a measurement assembly and a data-processing device and various combination would be chosen by the intended use of the equipment. Moreover, since an in-vivo counter have to detect a little radiation which transmit a human body organization, it needs to be cautious of reduction and discrimination of the influence of background radiation enough, when we evaluate radioactivity in the human body. Additionally, adequate calibration or inspection must be implemented for maintenance of measurement quality.
Bioassay is a method for determining the quantity of radionuclides in biological samples(mainly, excreta) that are collected from the subject and provides basic data for internal dose estimations. A main advantage of the bioassay is to be applicable to pure alpha/beta emitters that are difficult to be detected by means of direct measurements. The bioassay also has sufficient sensitivity even for actinides including plutonium. However, this method needs very time-consuming procedures before radioactivity measurements of the samples, such as pretreatments and radiochemical separations. These procedures are thus required to be speed-up from the viewpoint of radiation emergency medicine. This paper explains mainly the outline of bioassay methods for actinides.
It is required to measure not only external exposure but also internal exposure of personnel in Japan regulation, but it is difficult to measure internal exposure directly. Furthermore it is not realistic for facilities where is estimated for low exposure opportunity. However, it is possible to estimate internal exposure dose from breath which is mainly effect of internal exposure when they measure radioactivity in air. This paper shows description for method of internal exposure doses estimation from radioactivity in air, and for those reliability and managements.
Wide-palmed MIMOS II (Miniaturized Mössbauer Spectrometer II) were loaded on two Mars explorer Rovers(Spirit and Opportunity), and have worked successfully for identification of minerals on Mars surface. The MIMOS II are introduced together with the improved MIMOS IIA and an alpha fluorescent X-rays analyzer. Opportunity Rover arrived on the Meridiani planum of Mars in January, 2004, and found Jarosite in Victoria outcrop in March, 2004. Jarosite found is the first chemical evidence that shows the past presence of water on Mars because it contains hydroxide ion(OH−) in the structure. Further, goethite(α-FeOOH) detected in Clovis rocks on Columbia hills by Spirit Rover is also the important evidence of water presented in past. The Mössbauer parameters of Jarosite and the related minerals such as Mikasaite, Yavapaiite, and iron sulfate compounds are discussed herewith the structure and interesting property.