Radiation Safety
Debbie Peet, Emma Chung in Practical Medical Physics, 2021
An alternative assessment method is the use of a portable radioactive source. This is passed along the barrier at the same time as a contamination monitor (Figure 7.9) on the other side to identify any inconsistencies in the barrier’s attenuation. Ideally this should be performed with an americium-241 source, which closely replicates the diagnostic spectrum, however purchase and licencing of these sources can be prohibitive. A collimated technetium-99m source, absorbed into cotton wool to reduce contamination risks, can provide a practicable alternative although this provides a less accurate assessment due to the differences in x-ray energy between technetium and diagnostic X-rays. The lead equivalence of the wall can be estimated based on the known attenuation of the source that is used via a similar method indicated in Figure 7.7. For technetium sources, this measurement should be made under broad beam conditions. These estimates provide a convenient estimate but should be treated with caution due to errors involved in the measurement process.
Environmental Radioactivity and Radioecology
Gaetano Licitra, Giovanni d'Amore, Mauro Magnoni in Physical Agents in the Environment and Workplace, 2018
While the discovery of artificial radioactivity can be dated to 1934, when Irène Joliot-Curie and Frederic Joliot, who were awarded the Nobel Prize one year later, synthesised the first man-made radionuclide, phosphorus-30, 30P, bombarding 27Al with alpha particles, the relevance of artificial radioactivity rose dramatically only after World War II, during the Cold War: a great number of atmospheric nuclear explosions produced and spread all over the world a large quantity of fission fragments, neutron-activated products and transuranic elements (plutonium, americium, etc.), producing worldwide contamination.
Beta and Alpha Particle Autoradiography
Michael Ljungberg in Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Alpha autoradiography is also a useful tool in radiation toxicology studies. Tazrart and colleagues used iQID single-particle digital autoradiography to quantify and study the absorption in skin of americium and plutonium, in various chemical forms [84]. Tabatadze, and colleagues used iQID quantitative digital autoradiography to study the spatial distribution of 241Am within anatomical bone structures from individuals who received occupational exposure [49].
A review of the impact on the ecosystem after ionizing irradiation: wildlife population
Published in International Journal of Radiation Biology, 2022
Georgetta Cannon, Juliann G. Kiang
Twenty-one years later after the Chernobyl power plant explosion, various isotopes of plutonium, strontium-90, americium-241, and cesium-137 were still detected at high levels causing adverse biological effects across the nearby areas (Voitsekhovych et al. 2007). Wildlife continued to be exposed to substantial radiation doses after humans were evacuated from these areas. The half-life of cesium-137 is approximately 30 years and it decays by β emission to a metastable isomer of barium-137. The half-life of barium-137 isomer is 2 minutes. Subsequently, the metastable isomer emits γ radiation and becomes ground state barium (Baum et al. 2002). Food or water contaminated with cesium-137 that are ingested lead to internal β and γ radiation doses in addition to external radiation doses. The half-life of cesium-134 is about 2 years. Cesium-134 emits β particles. The half-life of strontium-90 is approximately 29 years. Strontium-90 emits pure β radiation. Most of the plutonium isotopes emit α particles, which are ionizing and harmful, but have a short penetration distance. The half-life of plutonium-241 is approximately 14 years. It emits β radiation to become americium-241. The half-life of americium-241 is 432 years, and it emits α particles to become neptunium-237, with a by-product of γ emissions (Baum et al. 2002). This is the composition of radiation released and retained in the soil, water and air across the Chernobyl landscape. In addition to external radiation exposure, ingestion of contaminated food and water by wildlife occurred from the beginning of the disaster and continues to the present.
Descriptive characteristics of occupational exposures and medical follow-up in the cohort of workers of the Siberian Group of Chemical Enterprises in Seversk, Russia
Published in International Journal of Radiation Biology, 2021
Andrey B. Karpov, Ravil M. Takhauov, Andrey G. Zerenkov, Yulia V. Semenova, Igor M. Bogdanov, Svetlana B. Kazantceva, Aleksey P. Blinov, Dmitriy E. Kalinkin, Galina V. Gorina, Olesya V. Litvinova, Yuriy D. Ermolaev, Elena B. Mironova, Mikhail B. Plaksin, Anas R. Takhauov, Lydia B. Zablotska
The main dose-creating radionuclide for workers employed at the SGCE is plutonium. Systematic monitoring for contamination by plutonium and uranium alpha-emitting radionuclides of SGCE workers was initiated in the mid-1950s (for uranium isotopes) and early-1960s (for plutonium) by specialized biophysical laboratory using the indirect method based on the radiochemical analysis of biological samples, and measuring levels of Pu/Am and U nuclides naturally excreted primarily with urine. Detection of Pu/Am and U activities in urine samples was based on the chemical separation of uranium and a mixture of plutonium and americium. The uranium radionuclides were precipitated with lanthanum fluoride and the mixture of plutonium americium was extracted with bismuth nitrate. Following precipitation, the activity of the sample was measured by solid scintillator.
Radiobiological and social considerations following a radiological terrorist attack; mechanisms, detection and mitigation: review of new research developments
Published in International Journal of Radiation Biology, 2022
Tanya Kugathasan, Carmel Mothersill
Out of the 8000 radioactive isotopes, there are approximately 13 isotopes that are considered the highest risk of terrorism (Anderson and Bokor 2013). These isotopes include tritium, cobalt 60, strontium 90, iodine 131, cesium 137, cesium 134, iridium 192, uranium 235, plutonium 238, americium 241 and californium 252. The fission of U-235 and Pu-239 are what create nuclear explosions. These isotopes are also used in nuclear reactors and can be very dangerous if inhaled (Radiation Emergency Medical Management 2021). Sr-90 is a fission product of uranium and is commonly used as radioactive tracers, heat source for navigational beacons and used in weather stations and space (Anderson and Bokor 2013). Tritium, Cs-134 and Cs-137 can also be produced through fusion in thermonuclear weapons (Anderson and Bokor 2013). Isotopes like Am-241, Cf-252 and Co-60 are used for various different applications and pose a threat because they are often stolen for terrorism-related activities. Am-241 is most commonly found in smoke detectors and is utilized in medical diagnostic devices, aircraft fuel gauges, thickness gauges and research (Anderson and Bokor 2013).
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