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Abstract: A simple method was developed for determination of 99Tc in low-level radioactive waste: Technetium-99 retained by a solid phase extraction disk was directly measured with imaging plates system. It was found that more than 97% of Tc were retained by the disk from a solution of pH 2 to 12, whereas depth profile of Tc in the disk, which greatly influences the counting efficiency, depended on solution pH. The present method was successfully applied to actual radioactive liquid waste samples arising from nuclear research facilities. [Copyright &y& Elsevier]

Abstract: In many X-ray clinics, the traditional photographic film has been replaced by an imaging plate (IP). The IP is re-usable and the purpose of this study was to test if image deterioration occurred after successive uses of the IP. The emphasis is placed on the efficiency of image formation and on image uniformity. In a cross-sectional study, 21 clinically used IPs were exposed with a standardized phantom imaging protocol. These IPs were in clinical use between one month and two years and the IPs were exposed between 191 and 3787 times. After digitizing, the mean pixel value (MPV) in a predefined image area was determined. The relation between MPV and IP uses was assessed. In a second experiment, image uniformity of 30 other clinically used IPs was visually inspected for artifacts on a diagnostic monitor. These IPs were in clinical use between one week and two years and exposed between 76 and 5373 times. The first experiment showed that no significant deterioration of the MPV with increasing usage count of the IP was present (p =0.15). The second experiment showed the appearance of clinically relevant artifacts on the IP before 3000 uses. It was concluded that the efficiency of the image formation process does not significantly deteriorate after successive use of IPs and is therefore not expected to limit their life span. Mechanical handling in the digitizer of the used system seems to set a limit to IP durability. Uniformity should therefore be checked regularly in clinical quality control. [Copyright &y& Elsevier]

Abstract: A muon beam intensity distribution perpendicular to the beam has been obtained using imaging plates that are commonly used in X-ray science, medical analysis, and transmission electron microscopy. The resolution of the imaging plates depends on the resolution of the imaging plate reader. We have used BAS-TR2025 imaging plates and a Bio-Imaging Analyzer (BAS-2500 or BAS-3000). The positional resolution is 50μm×50μm. When the beam is one kind, because a coincidence measurement is not necessary, the muon distribution perpendicular to the beam is taken in a very short time, and the spatial resolution is 50μm×50μm. Such a resolution cannot be obtained by the usual muon measuring method. This is quite convenient to adjust muon beams. When FLA-8000 or FLA-9000 is used, the resolution can be improved to 10μm×10μm. Such an intensity resolution of muon beams could not be imagined without using imaging plates. Obtained transmission muon images are also presented. This can be used as a non-destructive test. [Copyright &y& Elsevier]

Abstract: As an image recording medium for transmission positron microscopes, imaging plates are quite useful and powerful. Imaging plates are also quite sensitive and the photon-stimulated luminescence (PSL) is linearly proportional to the positron intensity in six digits (106). No bulky or expensive equipment is necessary to accommodate in vacuum. Imaging plates can be set under bright lights, this is different from the photographic films. Darkness is only required during exposure and transfer to a reader. Slow Positron Facility at KEK, Japan was used to study the effect of “mono-chromatic” positron beam. Specimens were set just in front of an imaging plate. After a certain time of exposure, the imaging plates were processed by a reader. Used imaging plates can be used repeatedly after erased by ultra-violet lights. Images through samples can be obtained. Similar experiments using non-monochromatic (white) positrons and electrons have been performed at Teikyo University of Science and Technology (TUST) and Research Reactor Institute, Kyoto Univ. (RRI). Sealed 22Na positron source can be conveniently used for non-destructive tests. [Copyright &y& Elsevier]