Optically stimulated luminescence (OSL) dosimeters developed originally for personal monitoring were applied to estimate ambient dose equivalent of local residents from natural environment. The OSL dosimeters were left indoors or outdoors in the Tokyo area. The radiation doses were measured every 3 months from July 2001 to June 2002. The yearly average was 0.59 mSv, which coincided with other reported values. Outdoor doses were a little higher than indoor ones. The doses varied depending on the structure of houses. It was concluded that the OSL dosimeters can be used to monitor the doses due to environmental radiation.
The radiation safety training course has been conducted for nurses of the university hospital by the collaboration of medical and educational staffs in Nagasaki University. This course was given for 6 hours covering basics of radiation, effects on human body, tips for radiation protection in clinical settings, and practical training, to more than 350 nurses overall. The pre-instruction survey by questionnaire revealed that 60% of nurses felt fears about radiation when they care for patients, which reduced to less than 15% in the post-instruction survey. The course also motivated nurses to give an answer patients' questions about radiation safety. In contrast, more than 30% of nurses were aware of neither their glass badge readings nor the maximum dose limit of radiation exposure even after the course. These results suggested that medical-educational collaborative traning for nurses were effective on reducing nurses' fears about radiation and that repeated and continuous education would be necessary to establish their practice for radiation protection.
An integrated radiation management system connecting an access control system, a stocktaking system of radioisotopes (RI), and a radioactive waste management system was developed by using sensing devices that require no contact. Radio-frequency identification data carriers (RFIDC) and barcodes were used as the sensing devices. RFIDC attached on glass dosimeters and RI tags were used to identify radiation workers and the RI contained in vials, respectively. Barcodes attached on plastic bags were used to identify radioactive wastes. The system has been in operation for 3 years and has proved to be effective for strict radiation management as well as being a labor saving device at our facility.
Penetration factors and related numerical data in “Manual of Practical Shield Calculation of Radiation Facilities (2000)”, which correspond to the irradiation geometries of point isotropic source in infinite thick material (PI), point isotropic source in finite thick material (PF) and vertical incident to finite thick material (VF), have been carefully examined. The shield calculation based on the PI geometry is usually performed with effective dose penetration factors of radioisotopes given in the “manual”. The present work clearly shows that such a calculation may lead to an overestimate more than twice larger, especially for thick shield of concrete and water. Employing the numerical data in the “manual”, we have fabricated a simple computer program for the estimation of penetration factors and effective doses of radioisotopes in the different irradiation geometries, i.e., PI, PF and VF. The program is also available to calculate the effective dose from a set of radioisotopes in the different positions, which is necessary for the γ-ray shielding of radioisotope facilities.