International Journal of PIXE

In Japan, air pollution due to atmospheric particulate matter has been a serious problem, especially at roadsides in megacity areas. However, it is difficult to widely cover roadside areas with a limited number of air pollution monitoring stations. Therefore we focused on a biomonitoring technique by using leaves of roadside trees. We sampled leaves of ginkgo (G. biloba) along major arteria roads in Osaka City, which is the third largest city in Japan. The particles retained on the surfaces of the sampled leaves were removed by ultrasonic cleaning in ethanol solution. The ethanol solution including particles was suctioned by an aspirator and particles were collected on a PTFE filter. Elements collected on the filter were quantified by particle induced X-ray emission (PIXE) analysis. It was found that the mass of traffic-related elements on the surfaces of sampled leaves correlated with the traffic density of large vehicles and the distance from the end of roadside to the sampling point. The ratios of mass of road dust-related elements on sampled leaves were almost similar to those of the road dust profile data. These results suggest the biomonitoring technique is an effective method to assess roadside air pollution.

In order to evaluate the quantitative values of atmospheric aerosol samples collected on filters, we investigated the effects of filter collection conditions (non-uniformity of collected particles) on analytical values and compared the quantitative values by means of PIXE and ICP-MS, using as the analytical sample PM_2.5 collected on filters in a monitoring survey of atmospheric fine aerosol over the Kanto area of Japan in summer 2013. The results were as follows: (i) With respect to the uniformity of filter collection, differences in concentrations were seen for S and Cl as well as elements thought to originate in soil (Al, Si, Ti and Fe) depending on the analysis point, suggesting that collection of sulfate particles, chloride particles, and soil particles on filters was not uniform. (ii) According to a comparison of quantitative values yielded by PIXE and ICP-MS, ICP-MS values were lower than PIXE values for Mg, Al, Si, Ti and Fe, with Mg and Si being markedly lower. On the other hand, ICP-MS values were higher than PIXE values for Na, K, Ca and Zn. (iii) According to the results of measurement of NIST reference material and PM_2.5 samples by means of PIXE and ICP-MS, Mg, Al, Si, Ca, Ti, Fe and Zn showed the same tendency. However, Na and K were opposite.

This research looks at the correlation between the quantity of nutrients taken as minerals determined by PIXE analysis and mineral intake calculated in accordance with menu records collected via a total food duplicate method survey conducted on agricultural workers from four inland areas of Iwate Prefecture. Among the major nutrients and minerals taken over a 24 h period, intakes of calorie and carbohydrate of both sexes were found to be slightly high for the off-season, which indicated they had kept on a diet suited for the busy farming season. Intakes of calcium, iron and dietary fiber were also high. While 31 elements were identified from the hair samples collected from subjects, the elements found in all subjects were sulfur, calcium, iron, copper, zinc, and bromine. In many of the elements detected, a great difference between the maximum and minimum values was found. As for potassium, sodium, calcium, magnesium, phosphorus, iron, copper, of which excess or deficiency could affect health, we examined whether their element content in hair correlates with their amount taken in the body through meals. However, no clear correlation between the two, the elements in hair and meals, was found.

This investigation focuses on the arsenic contamination problems in tube well groundwater systems and the different forms of arsenic and other toxic elements accumulated in human hair samples taken in a rural area of Allahabad, Uttar Pradesh, India. The local residents at the study site depend on groundwater as their major source of household water. The oxidation reduction potential (ORP) and pH of groundwater samples were measured directly after the sampling of groundwater. Arsenic concentrations were measured directly in water samples by a colorimetric arsenic analysis kit after the water was pumped from a tube well and/or at a nearby laboratory. Human hair samples from the residents of the villages in the study site were analyzed by PIXE to measure a wide range of elements. An atomic absorption spectrometer was also used to measure arsenic concentrations. The results indicated that the concentrations of arsenic in groundwater and human hair were significantly higher in the village of Bada Kanjasa than in the villages of Kanua and Chota Kanjasa (P< 0.05), clearly indicating that the higher arsenic concentration in groundwater reflected the accumulation of arsenic in human hair in the residents of Bada Kanjasa. The PIXE analysis also revealed an unusually high concentration of lead in human hair samples from Chota Kanjasa. Although the actual health effects and the detailed exposure mechanisms remain to be investigated, lead pollution is suspected to be the source of the exposure.

The effects of spraying mineral water onto agricultural crops on their yields and mineral contents were examined. We sprayed a solution containing a large quantity of essential minerals onto the leaves of various agricultural crops every other week for a few months. The mineral concentrations in the agricultural crops and of the sprayed solution were measured by particle induced X-ray emission (PIXE). It was found that the effect of spraying mineral water on the crops was remarkable, especially for rice and soybeans, for which the yields became nearly three times higher and the concentrations of many essential minerals increased in their stems and leaves. However, no clear increase in the mineral contents was observed for polished rice. In addition, not all of the farm products showed positive effects. This indicates that an effective method and timing of spraying mineral water should be examined depending on the conditions of each individual agricultural crop.

We aimed to image and treat the lung metastases of MM48 breast cancer cells in C3He/N mice by using microcapsules that release liposome-protamine-hyaluronic acid nanoparticles (LPH-NP) in response to two radiation sessions. In session one, computed tomography (CT)-detectable microcapsules containing P-selectin and 5% iopamiron were mixed with a 1 mL solution of 4% alginate, 3% hyaluronate, 1 mg ascorbate, and 1 μg/mL P-selectin. This was sprayed into 0.5 mmol/L FeCl₂ containing 1 μg/mL VEGFR-1/2 antibodies (Abs). The mice were intravenously injected with microcapsules, which released the P-selectin, and then a CT study was performed to detect lung metastases. After the CT evaluation, the mice received 10 or 20 Gy (140 keV) of X-ray radiation to the lungs. In session two, carboplatin-LPH-NP was released into the tumor, which was treated with another dose of radiation. To do this, carboplatin LPH-NP was mixed with the cocktail used in session one and sprayed into 0.5 mmol/L FeCl₂ containing 1 μg/mL anti-P-selectin Abs. Microcapsules (1 × 10¹⁰) were injected intravenously and then interacted with the P-selectin. The released carboplatin LPH-NP attacked lung metastases synergistically with radiation, which resulted in further reduction of the lung metastases.

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.

Many studies have been performed to determine the associations between the amounts of minerals present in hair and the health status, toward developing new approaches for disease prevention and prediction. Unfortunately, because of the highly variable results, which can be caused by many factors, there is no definitive consensus on the validity of these values in disease management. A previous proton-induced X-ray emission (PIXE) study of mothers and infants examined the association between hair minerals and the onset of atopic dermatitis in infants. For many of the minerals identified and analyzed, highly variable intra-individual variations proved problematic, and may have obscured any connections between disease states and the mineral levels. We feel that better statistical modeling of these intra-individual variations might lead to a better understanding of the associations between the hair mineral levels and the patient health status. This report examines the statistical nature of the intra-individual variations due to locations of hair strands and those due to the physical errors of the PIXE experiments. The results for Cu, Fe, Sr and Se are presented.

The purpose of our research is to identify causative metals by using particle-induced X-ray emission (PIXE) method to directly analyze trace elements in the oral mucosa with oral lichen planus (OLP). Subjects were 72 patients with OLP, and the patients are 25 men and 47 women, with a mean age of 60.1 years (OLP group). The control is elemental analysis data by PIXE method of 100 cases of the oral mucosa of healthy persons (control group). Seventeen essential elements and 12 contaminating elements were detected from the oral mucosa of the OLP and control groups. As to appearance ratio of elements in oral mucosa, among the contaminating elements, levels of Al, Ga, Sb, Hg and Pb were significantly lower, whereas Au and Y were significantly higher in the OLP group than in the control group. About concentration of elements in oral mucosa, the contaminating elements in the oral mucosa of the OLP group had a lower appearance ratio than in the control but each of the contaminating elements was more abundant. Among 25 subjects in the OLP group and seven in the control group, serum, oral mucosa and saliva were collected from the same individual. Abundance in serum and saliva varied depending on the element, but in general, a tendency was seen for contaminating elements to be more abundant in saliva than in serum and for essential elements to be more abundant in serum than in saliva.

A syringe needle-type proton-induced monochromatic X-ray source was proposed to solve the issue that could occur in practical brachytherapy, such as loss of seed sources and radiation exposure to surgical staff. This paper discusses comparison between experimental results and a Monte Carlo numerical simulation of the dose distribution around the needle. Some simulation results for different source designs are presented as a first step of the design optimization.

In this paper, we propose a highly-selective radiotherapy based on monochromatic X-rays and cancer-targeting gold nanoparticle (GNP) sensitizer. In order to deliver the low-energy monochromatic X-rays which selectively ionize the Au L-shell into the cancerous tissue deep inside the patient’s body, we employ a syringe-needle type X-ray source driven by an MeV proton beam. From a simple numerical evaluation, we found that optimization of the primary X-ray energy was essential to enhance the dose around the nanoparticle. In order to confirm the above idea qualitatively, we performed a simulation experiment in the atmosphere, where 100 nm Au foils were used instead of the GNPs. The experimental result showed that the dose around the Au foils was much higher than that at positions away from the foils, owing to short-range secondary electrons from the foils.

In this paper, methods of quantitative elemental analysis of very small quantity of cultured cells were developed. First of all, an internal-standard method for the solution containing cells whose density is more than 1 × 10⁶ cells/mL was established and then a standard-free method for cultured cells was developed. It was confirmed that the method allows us to quantitatively analyze more than 25 elements in the samples containing only 20,000 cells. Also, the methods for removing cultured cells from a flask were examined in order to improve accuracy and sensitivity of analysis since the use of trypsin and PBS sometimes brings a large amount of sodium, phosphorus and potassium, which have direct effect upon accuracy of analysis based on the standard-free method. It was found that the method of removing cells with a scraper without using trypsin and PBS is the best manner. Also, the effects of using thinner backing materials were examined in order to improve sensitivity of analyses. It is expected that accurate analysis of samples containing nearly two thousand cells is possible on the basis of the standard-free method when using a thinner backing material.

Ion beam induced luminescence (IBIL) analysis was performed on organic targets are typical organic contaminants in aerosols. An external proton microbeam with an energy of 3 MeV was selected as the probe for the continuous IBIL measurement. Commercially available organic standards, including common amino acids (nicotinamide adenine dinucleotide, riboflavin and tryptophan) and a polycyclic aromatic hydrocarbon (benzo[a]pyrene), were used to test the analysis. Differences in chemical composition were distinguished by the shape of the IBIL spectrum in the UV/visible/near-IR region (200–900 nm). The IBIL spectrum changed as the proton irradiation damage increased. These results suggest that qualitative characterization of organic materials might be possible through the continuous measurement of IBIL spectra.