Radiophotoluminescence (RPL) photography has been proposed for the measurement of the spatial dose distribution of high radiation fields. A pulsed UV LED floodlight was prepared as an excitation light source for the RPL photography. The fluorescence image of RPL material was observed by a gated intensified CCD camera. In a preliminary experiment, several tens of spherical RPL detectors were placed near an intense 60Co source. The pulsed UV-LED illuminator and the gated intensified camera were pulse-operated to obtain the RPL photograph of the spherical RPL detectors. The spatial dose distribution was calculated from the brightness values of obtained RPL images.
Distribution coefficients of strontium, cesium, uranium, plutonium and americium on pulverized mortars and aggregates were measured to estimate infiltration of such radionuclides in concretes using a model. The model was constructed based on partition equilibrium. Depth profiles for the nuclides in columns experiments were compared with that estimated with the model. Both depth profiles agree with each other. In addition, we estimated the depth profiles for the nuclides in concrete. According to the model, the atoms of Sr infiltrate much deeply in mortar than the other nuclides.
The biological dosemeter that directly reflects cellular responses to ionizing radiations in living organisms would be useful for the protection of human health against exposures. We are aiming at developing a novel dosimetric system using DNA molecules as a radiation sensor. DNA molecules are irradiated and the resulting DNA damages are quantified by real-time PCR (quantitative PCR, qPCR) reactions. We investigated DNA lesions caused by gamma ray or carbon ion particle irradiation and revealed that the extent of DNA amplification negatively correlated with the greatness of LET of exposed radiations. While ionizing radiations elicit not only DNA strand breaks but 8-hydroxy-2′-deoxyguanosine (8-OHdG) production, the amount of 8-OHdG produced by the high-LET carbon ion particle irradiation was at a similar level to that by low-LET gamma ray irradiation, demonstrating that 8-OHdG production was not affected by the greatness of LET. These results suggest that the extent of DNA strand breaks, not the amount of base damages such as 8-OHdG, is influenced by the greatness of LET and causes negative effect on DNA amplification.
The system of automatically adjusting an appropriate radiopharmaceutical dose for nuclear medicine examinations was developed in this study. This system can calculate appropriate radiopharmaceutical dose on the base of a guideline, and adjust the quantity of solution in syringe by inputting some patient information and the substance of examination. And adjusted the quantity of solution, the text data are saved as information on PC. Further the label for pasting on syringe is outputted with a printer. The difference between the quantity of solution in syringe filled at dispenser and the calculated volume with PC is 2% or less, and it was shown that it is satisfactory in the practical needs. This system is efficient of a quality assurance of nuclear medicine examinations.
The energy spectra and dose equivalent rates (H1cm and H70μm) of direct and scattered X-rays from various targets of X-ray generation equipment were measured by three kinds of radiation monitors: an ionizing chamber, a GM survey meter and a CdTe semiconductor. The effective energies of direct X-rays from Cr and Cu targets applied at 40 kV are 8.1 keV and 11.6 keV, respectively, which are larger by about 2-3 keV than the energy of each characteristic Kα X-ray. The effective energies of direct X-ray from Mo, Ag and W targets at 40 kV are 17.1 keV, 14.5 keV and 13.4 keV, respectively, which are lower than the energy of each characteristic Kα X-ray. On the other hands, the effective energies of scattered X-rays from all targets are almost the same (12.4±0.34 keV) because the scattered X-rays are affected by fluorescent X-rays of Pb and Sn on shielding glass. The calibration factors to convert from count rates to dose equivalent rates (H1cm and H70μm) were obtained for a wide mouthed GM survey meter and a CdTe semiconductor. The above results enable us to easily estimate the low dose equivalent rates for leaked or scattered X-rays of X-ray generation instruments.
Nagasaki University Radioisotope Research Center introduced a small-animal PET/SPECT/CT imaging system as new technology for biomedical research using radioisotopes in 2012. From 2014, the new support system has been operated to promote molecular imaging research, including an assignment of specialist, consultation for protocol set-up, public relations, and technical assistance. The molecular imaging system with those supports resulted in the increases of machine operating rate, the number of machine users, the amount of radioisotopes received, and revenue by facility fee. New research achievements by molecular imaging technology were also found as international publications, reports in scientific meetings, and research budgets. Introduction of PET/SPECT coupled with intensive support seems to provide an effective approach to expand the demand of the radioisotope along with to enhance frontier research activities.
An optically stimulated luminescence reader (Risø TL/OSL DA-20) was installed in the Toki Research Institute of Isotope Geology and Geochronology (Toki-shi, Gifu Prefecture), Japan Atomic Energy Agency (JAEA) for dating the geological sample. An accumulated dose in the sample is obtained using the reader. Sealed beta source of strontium-90 is required to be mounted on the reader because repeated artificial irradiation is necessary for the accumulated dose estimation. However, there are not many introduction examples for the reader domestically, and the information as to radiation control of the reader is limited. We therefore report here the process of source loading on the reader and radiation control associated with the use of the source.
We developed a Web analysis system, which analyzes automatically a data file outputted from the germanium detector. This system is used on a Web server. This consists of a Perl script, which performs operation from a Web browser as CGI, and the statistical language R scripts which analyze data and make graphs. By this system, the work accompanying analysis can be simplified and processing result can be obtained quickly. By using our system, the processing time from reading a spectrum file to showing results to the Web is approximately 250 times as quick as the conventional manual method.
A reasonable area monitor system for monitoring the radiation dose of X and γ rays in five places was composed by using dosimeters having USB interface, popular network devices, a personal computer and so on. The area monitor system had stably operated over more than 4 months after installed in a radiation facility. Dose rates which had been indicated by the reasonable area monitor system corresponded to them which were indicated in the regular monitoring performed every month over the past 5 years. The reasonable area monitor system must be useful for consecutive monitoring of the radiation dose in and around radiation facilities in the same way as a ready-made system.
The consciousness of radioactive pollution originating from the Fukushima-Daiichi nuclear power plant accident was investigated in the student of the department of early childhood care and education using questionnaires because the teaching manual of environmental pollution was studied in the subject childcare method of instruction (environment). Students were not concerned about consuming the farm products from Fukushima; however, they were concerned about children consuming them because the residents were anxious for their health by effects of radiation in Fukushima. It is necessary to draw the interest of students because they tend to forget the content of the lessons on radiation and radioactive pollution.