We investigated the timing of arrival of the contaminated air from Fukushima Dai-ichi Nuclear Power Plant （FDNPP） by using the exhaust monitor of the RI facility, the radioactivity of 131I in environmental water in the Komaba 1 Campus, the University of Tokyo, Meguro-ku, Tokyo after FDNPP on March 2011. The behavior of the exhaust monitor from 15 to 16 March was in agreement with other monitoring post at 5.2 km distance, which indicated that the monitor was effective for estimation for reaching of dry deposition. The radioactivity of 131I in the paddle water was observed from 2,830 to 11,100 Bq/kg, estimating that radioactivity of 131I in rain fell on 21 March was higher than that of paddle water.
It is important to reduce avoidable radiation exposure of health care workers and patients at radiography room in hospitals. For this purpose, teaching methods/tools that can explain basics of radiation protection is useful. Here, we propose a new teaching tool for radiation protection at a general radiography room. X-ray scattering at the general radiography room is mapped by using a Monte Carlo simulation code, PHITS. The radiography room is modeled with a simple geometric form. Therefore, the model can be changed easily to fit each radiography room even by a PHITS beginner. Visualization of X-ray scattering in each radiography room help the effective understanding of radiation protection. Our teaching tool is useful to reduce the unnecessary radiation exposure in radiography rooms.
90Sr (approx. 29-years half life time) is a beta emission radionuclide and one of the typical fission products produced from uranium fuels. 90Sr is a pure β-ray emitter nuclide and does not emit gamma-rays; thus it is difficult to measure 90Sr compared with γ-ray emitted radionuclides. For the demand of rapid measurement of 90Sr, various analytical methods have been reported. Herein, these analytical systems for 90Sr were reviewed, in particular, the application of inductively coupled plasma quadrupole mass-spectrometry (ICP-QMS) for 90Sr was focused on. The studies on ICP-MS techniques have been progressing since Fukushima Dai-ichi Nuclear Power Plant Accident.
The CyberKnife® (CK) system is a radiotherapy equipment that combines an X-ray irradiator and robotic arms that were developed at the end of the last century. Through flexibility of the system, CK can achieve precious radiotherapy by selectively irradiating tumor lesions. Useful applications of this treatment include frame-free fractionated stereotactic radiotherapy for intracranial tumors, and tumor-tracking radiotherapy for pulmonary and hepatic lesions under the respiratory motion. This treatment is also effective for local control of bone metastases. Since a wide range of clinical application is feasible, stereotactic radiotherapy by using CK system is an important option in radiotherapy.