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To confirm the quantitative accuracy of PIXE analysis instruments, we measured NIST SRM air particles on filter media using different types of PIXE analysis instrument: in-air micro-PIXE, in-air PIXE, in-vacuum PIXE, and in-vacuum micro-PIXE. Then, we compared the measured values with certified values and reference values of NIST SRM. We found that the quantitative values of the NIST SRM filter media measured with each PIXE instrument were within 90% to 110% of the NIST-certified and reference values for most elements. In particular, the quantitative values of major elements ranged from 90% to 110% for the in-air PIXE (Kyoto University), the in-vacuum PIXE, and the in-vacuum micro-PIXE at Tohoku University, and the relative errors are also small. These results will aid in determining the quantitative values of atmospheric particles on filter samples.

Micro-PIXE is capable of providing spatial distributions of elements in the micro-meter scale and its application to biology is useful to elucidate the cellular metabolism. Since, in this method, a sample target is usually irradiated with proton or α-particle beams in vacuum, beam heating results in evaporation of volatile elements and shrinking of the sample. In order to avoid these side effects, we previously developed a technique of in-air micro-PIXE analysis for samples of cultured cells. In addition to these, analysis of exposed tissue samples from living subjects is highly desirable in biological and medical research. Here, we describe a technique of in-air micro-PIXE analysis of such tissue samples. The target samples of exposed tissue slices from a Donryu rat, in which a tumor had been transplanted, were analyzed with proton micro-beams of 2.6 MeV. We report that the shape of cells and the distribution of volatile elements in the tissue sample remain uncharged when using a target preparation based on a freeze-drying method.

A program was started to create a new medical scientific field, which involves radiation oncology and nuclear medicine, utilizing advanced accelerator and ion beam technology. An in-air micro-PIXE analyzer system, which is among the most important technical aspects of the program, was upgraded to improve the accuracy of elemental mapping for samples with thickness variation in the scope of microbeam scanning. In order to address important bio-medical problems in cancer, the intracellular dynamics of trace elements according to the development mechanism of diseases were studied using this system. This paper outlines the program, showing correction of micro-PIXE elemental map by STIM analysis and the preliminary application results.

The present study aims to analyze the elemental distribution in erythrocytes from five hemodialysis patients treated with erythropoietin in comparison to four healthy controls. Using in-air micro-PIXE we determined that iron dots were distributed in the peripheral region of control erythrocytes, which were made up of two to four compartments. Iron dots tend to aggregate partially in hemodialysis patients. Calcium was rendered to form small dense nodules in erythrocytes of controls, and small dense nodules became marked in some hemodialysis patients. Nodular formation of phosphorous was weakened in both control and hemodialysis patients. Potassium aggregated focally and formed small dense granules in erythrocytes of healthy controls. On the other hand, hemodialysis patients showed enrichment of potassium, with diffuse spreading partially to all over erythrocytes. These findings indicate that in-air micro-PIXE is a useful tool for analyzing the elemental distributions in erythrocytes of hemodialysis patients.

The present study aimed to evaluate the relationship between elemental changes in erythrocytes and hepatogenous anemia. Five chronic hepatitis C, five liver cirrhosis (HCV positive) and three healthy controls were enrolled in this study.

Using in-air micro-PIXE, we determined that K rods formed small nodule and Cl rods distributed diffusely in all over erythrocytes, resulting in disappearance of the donut-like pattern of erythrocytes. These findings may reect the alternation of ery- throcyte membrane structures. Fe dots were divided into two to four compartments in erythrocytes of control group, and the similar distribution of Fe rods was shown in those of chronic hepatitis and liver cirrhosis. Na concentrations analyzed by in-vacuum PIXE were significantly higher in liver cirrhosis than in chronic hepatitis and control, possibly because of the disturbance of Na–K pump. Present study suggests that the alternation of erythrocyte membrane and Na–K pump failure may participate in hepatogenous anemia accompanied with liver cirrhosis.