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Beta and Alpha Particle Autoradiography
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Anders Örbom, Brian W. Miller, Tom Bäck
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].
Radiation Safety
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
Debbie Peet, Elizabeth Davies, Richard Raynor, Alimul Chowdhury
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.
Home and Away
Published in Alan Perkins, Life and Death Rays, 2021
Excluding radon and possibly some old family heirlooms in the attic, such as watches, clocks, Vaseline glass and medical appliances that may have contained radioactivity, the only other source of radioactivity you might find in the home might be smoke detectors. These life-saving devices often contain a small amount of americium-24, amounting to around 37 kBq. Americium-241 is an alpha emitter with a half-life of 432 years. As it slowly decays, it produces a negligible amount of gamma radiation, so there is no external hazard to people in rooms and building. These smoke detectors have two ionisation detectors: one is sealed and works as a reference chamber and the other is open to the air. Under normal conditions the current in both chambers is the same, but if smoke particles enter the open chamber a change in current is detected and this activates the alarm. Some European countries and American states have now prohibited the use of this type of alarm in favour of the newer optical photoelectric detectors that do not contain any radioactivity. A potential hazard exists with radioactive smoke detectors if a large number of devices are not stored securely or if they are disposed of inappropriately. The americium-241 in these devices is contained in a sealed container and is only a risk to health if the container is punctured and the material extracted. A person would have to open the sealed chamber and ingest or inhale the americium for the risk to be significant and why would anyone want to do that?
Adverse outcome pathways and linkages to transcriptomic effects relevant to ionizing radiation injury
Published in International Journal of Radiation Biology, 2022
Jihang Yu, Wangshu Tu, Andrea Payne, Chris Rudyk, Sarita Cuadros Sanchez, Saadia Khilji, Premkumari Kumarathasan, Sanjeena Subedi, Brittany Haley, Alicia Wong, Catalina Anghel, Yi Wang, Vinita Chauhan
The selected 43 references comprised exposures across different radiation types including x-rays, gamma rays, alpha particles produced by radon and other emitters, and energetic heavy ions (Figure 1A). Most studies were focused on x- or gamma rays (13 and 11, respectively), followed by alpha particles from radon gas and other emitters such as americium-241 (241Am) or plutonium-238 (238Pu) (7 and 11, respectively). Studies directly relevant to energetic heavy ions exposure were minimal, including three studies on iron, two studies on silicon, one study on space radiation, and one on iodine. Regarding the model types, around 1/3 of the collected data were from in vivo studies, including mice, rats, and fruit flies; 2/3 of the studies were in vitro conducted mostly on human-derived cell models, either immortalized or cancer cell lines or primary cells harvested from patients (Figure 1B and C). Transcriptomic data were derived using various experimental platforms, but mainly qRT-PCR (64.3%) and microarray (26.8%) (Figure 1D).
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.
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
RDD’s can be formed from components of fertilizer or even a plastic explosive (Hall and Giaccia 2014). Radionuclides such as Americium-241 are often misused in dirty bombs and are not easily detectable because they mainly emit alpha radiation (Rump et al. 2021). Often, radionuclides are stolen from nuclear medicine departments or university laboratories. IAEA shows records of more than 100 radionuclides that were stolen in 2016 (Gale and Armitage 2018). There have also been reports that show theft of nuclear fuel rods from the U.K and U.S nuclear power facilities (Gale and Armitage 2018). This places major concerns and complex investigations on the possession of these missing radionuclides. An example of an IND is a 10-kiloton nuclear device that was stolen from a nuclear facility in the former Soviet Union with the intention of detonating it at the center of Washington D.C (Gale and Armitage 2018). This scenario would have resulted in complete destruction within 1 km of the epicenter and extended out to 6 km (Gale and Armitage 2018). This would also disrupt communication caused by the electromagnetic forces from the detonated