Search

Copyright of Nuclear Safety is the property of Nuclear & Radiation Safety Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The increasing development of the atomic energy industry has brought about potential safety hazards such as nuclear leakage and nuclear pollution. People must take strict protective measures to protect the health of nuclear facilities staffs and environmental safety. Among the various types of nuclear radiation? neutrons and gamma rays have the strongest penetrability, which are the most difficult to be shielded. However, traditional neutron shielding materials such as boron, water, polyethylene, and gam ma-ray shielding materials such as lead，iron, and tungsten have single shielding functions, limited shielding performance, or poor thermodynamic properties, making it difficult to meet modern radiological protection requirements. Tn this regard, composite materials can combine the advantages of various raw materials which can realize the complementary performance and expand application area of the radiation shielding materials. At present? a large number of composite shielding materials have been developed and applied. According to different substrates? it can be divided into five categories as follow: (1) polymer-based composite shielding materials; (2) metal-based composite shielding materials; (3) shielding concrete; (4) glass-based composite shielding materials; (5) ceramic-based composite shielding materials. Tn this paper, the mechanism of the interaction between neutrons and gamma rays and atoms is briefly summarized. The research progress of composite shielding materials? and the research content and characteristics of each type of composite shielding materials are detailed reviewed. Tn addition，the problems to be solved in the current research about composite shielding materials are pointed out and future research trends are predicted. [ABSTRACT FROM AUTHOR]

Through radiation measurement of the patients after brachytherapy with radioiodine seeds for malignant tumor at different distances and shielding condition, the importance, optimization and individualization of the radiological protection are well recognized. The 35 patients were randomly selected in the minimally invasive interventional ward of Peking University Shenzhen Hospital who underwent brachytherapy for malignant tumor with radioiodine seeds. Within 2 hours after the brachytherapy, the radiation of the patients without shielding, with 0.25 mmPb and 0.5 mmPb shielding were detected by an x-γ ray detector at different distances (equivalent dose rate). The results were analysed by SPSS19.0 t test. Annual equivalent dose was calculated by the average close contact time (two hours everyone per day). The average annual equivalent dose of the 35 patients without shielding was below 20 mSv at 0.5 meter, close to the public limit 1 mSv at 2 meters and equivalent to the background at 4 meters. Under 0.25 mmPb shielding, 6 patients’ radiation was still above the pubic limit, although the average radiation of the 35 patients was below the pubic limit; under 0.5 mmPb shielding, all patients’ radiation was nearly equivalent to the background at 0 meter. The results showed that among the time, distance and shielded protection, the individual radiological protection was especially important. The 0.25 mmPb lead cushion was the most commonly used shield. The 0.5 mmPb lead cushion also should be used in case of the large number of radioiodine seeds implantation and/or more superficial implant site, so as to ensure the individualization and optimization in radiological protection.