Is It Safe to Eat Fish?

No abstract available.

Determining TG-43 brachytherapy dosimetry parameters and dose distribution for a [131]Cs source model CS-1

Monte Carlo determination of TG-43 brachytherapy dosimetry parameters and dose distribution calculation for [131]Cs source model CS-1 are presented in this study. The dose distribution was calculated around the [131]Cs Model CS-1 located in the center of 30 cm x 30 cm x 30 cm water, and soft tissue phantoms cube using MCNP code by Monte Carlo method. The percentage depth dose [PDD] variation along the different axis, parallel and perpendicular, the source was calculated. Then, the isodose curves for 100%, 75%, 50% and 25% PDD were constructed. Finally, F[r, theta] and g[r] dosimetry parameters of TG-43 protocol have been determined. Results obtained show that the Monte Carlo method could only calculate dose deposition in high gradient region, near the source, accurately. The energy cut off was found to be 1 eV and the error in the calculations was less than 2%. The isodose curves of the CS-1 [131]Cs source were constructed from dose calculation by MCNP code. The calculated dosimetry parameters for the source were in agreement with previously published results

Safety of handling of radioactive isotopes in some of Alexandria medical centres

The isotopic method represents a powerful tool for the solution of numerous problems in biology, physiology, chemistry, physics and other sciences. It is true that the use of isotopes as a scientific tool is not new, but it is only in recent years that isotopes became available in such variety and quantity as to make their use more widespread. Handling of such radioactive isotope sources, therapeutic or diagnostic, and their waste management presents one of the serious environmental health problems, especially in developing countries. The work aimed to evaluate the safety of handling of radioactive isotopes in five isotope therapeutic units [Cobalt-60 and Cesium-137] and seven radioactive isotope diagnostic laboratories [Iodine-131, Iodine-125, Thallium-201, C-14] which covers most of radioactive medical and research centers in Alexandria. The data of radioactive isotope doses was measured by Portable Geiger meter and included different handling positions, storing places, and radioactive waste management. The study revealed good and safe handling conditions in some of the heavy isotope units [3,4 and 5], but units [1 and 2] need repair and maintainance which has already started. Unit [5], also, needs more leaded isolation on the door corners to decrease the dose outside the room. Concerning diagnostic laboratories of unsealed sources, the results indicated a permissible level of doses in most laboratories, which means highly safe handling conditions except the therapeutic glands' laboratory at treatment position by Iodine-131 to patients. It could be concluded that the application of radiation protection programme through Atomic Energy Authority is taking good care especially in unsealed isotope laboratories. When dealing with acute impacts of radioactive hazards, it is important to avoid shocks or accidents by the precautionary principle of surveillance through the safe handling and management of such materials.It is desirable to keep the average individual exposure in the population as low as oossible to avoid late and genetic effects of radiation

Césio-137 em leite produzido em fazendas da regiäo de Angra dos Reis RJ / Cesium-137 in milk produced in farms of the region of Angra dos Reis, RJ

Nos efluentes líquidos e gasosos a serem descarregados no meio ambiente pela Central Nuclear Almirante Alvaro Alberto, em Angra dos Reis, os radionuclídeos de maior impacto potencial para a populaçäo säo trítio e radioisótopos de Cs,I, Co e Sr. Durante a fase preliminar dom programa pré-operacional de monitoraçäo radiológica ambiental, realizado por FURNASD Centrais Elétricas S.A., 137 Cs proveniente de resíduos de explosöes necleares, realizadas no passado na atmosfera, foi detectado em leite de apenas uma das fazendas incluídas nq programa. Este resultado pareceu estranho,levando a crer na existência de uma anomalia no solo fazenda, que tornasse o 137 Cs mais disponível do que o habitual para absorçäo por plantas, como já observado em alguns países. Visando esclarecer este assunto o Lab.de Radioisótopos do Instituto de Biofísica e o Lab.de Radiocologia de FURNAS decidiram uma série de análises de 137 Cs em amostras de leite,capim e solos coletados periodicamente nas quatro fazendas do programa. Os resultados obtidos demostraram a näo existência de uma naomalia de comportamento de 137 Cs no solo na regiäo. Os teores de 137 Cs em leite variaram de 0,05 a 0,93 Bq/1, mas os valores médios, nas quatro fazendas, näo eram estatisticamente diferentes. Numa das fazendas do programa obvservaram-se picos ocasionais da concentraçäo de 137Cs em leite. Estes parecem ser devidos ao manejo do gado, com permanência temporária em áreas nas quais os teores de 137Cs em solo e pasto säo mais elevados do que nas demais áreas da mesm5 azenda, e da regiäo em geral, devido à influência de micro-clima e erosäo de solo superficial