It is important to measure scattered radiation in diagnostic radiology in terms of evaluation of occupational exposure and leakage radiation dose. Recently, Unfors RaySafe (Sweden) released a solid-state survey sensor aimed at expanding RaySafe X2 system. However, there are no detailed reports regarding the performance, which includes energy dependence and angular dependence, of X2 survey meter. The purpose of this study was to evaluate the performance of X2 survey meter. Experiments were conducted to compare the performance of X2 survey meter with that of an ionization chamber survey meter. The results showed that the fundamental performance of X2 survey meter were equal to or superior to that of an ionization chamber survey meter. In addition, X2 survey meter is easy to handle. The study concludes that X2 survey meter has adequate performance for measurement of scattered radiation in diagnostic radiology.
The current concentrations of radiocesium (137Cs) on upper surface of cherry tree branch barks of the South Tohoku District of Japan are high. In 2017, these concentrations decreased to about half of that in 2014 When the accident at the Chernobyl Nuclear Power Plant occurred, the 137Cs concentrations on cherry tree bark surfaces in the area were on same level as that in the Northern Fukushima Prefecture. This was about 1/100 of the concentration in Fukushima City in 2016. Autoradiography of the cherry tree bark samples obtained from the area revealed weak radioactive spots on the surface of the barks. 137Cs pollution in cherry tree barks in the South Tohoku District is expected to decrease to about 1/100 of the initial concentration after thirty years.
The confusion after the Fukushima-Daiichi NPP accident may be attributable in part to the failure of early emergency monitoring by the government. The governmental emergency monitoring measures had been established but did not work for several reasons including destruction of radiation monitoring posts and insufficient preparedness for such a great disaster more than expected. The approved radiation facilities with technical and human resources may have ability to play a role in emergency situations outside their radiation control area, and in fact, emergency environmental sampling, monitoring, and disclosure of the results to the public by the radiation facilities were reported. These experiences indicate the possibility that the emergency monitoring platform by radiation facilities will be organized. To assess this possibility quantitatively, we conducted a current situation survey to the educational radiation facilities about their experience, intention and future considerations regarding the emergency responses. The results demonstrated that more than half of 72 responders had taken various measures after the Fukushima-Daiichi NPP accident such as monitoring to know radiological situation of their environment, however; the information was not shared due to lack of the common framework. Therefore, the 59 facilities out of 72 expressed the intention to join the emergency monitoring platform if it is organized. These results clearly suggest that the organized emergency monitoring platform by educational radiation facilities could be established, as a complemental system from the academia to the public.
At Hokkaido university, CoSTEP, we started risk communication classes from 2014 and are trying to position it in the science communicator training course. In this class, we focus on the theme of radiation risk problems brought by the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Plant Accident and to create opportunities for interactions of 3 days at Fukushima. This field study brings changes in risk perception to students. This method also has the educational effect that makes it possible for students to recognize not only objective risk assessment but also the important aspect of risk communication based on social context and subjectivity.
For achieving reasonable radiation management of short-lived alpha emitters in Japan, an actual example of radiation management in Sweden was reported. Many of safe handling technics of unsealed radioisotope were common in Japan; many advanced technologies were used especially in the equipment. On other hand, Swedish radiation management was more reasonable than Japan. As an example, hot experiments are carried out while the exhaust port of a glove box was not completely connected to the exhaust duct in ventilated workroom.