Radionuclides in water *
Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse in Routledge Handbook of Water and Health, 2015
Cesium-137 is an anthropogenic radionuclide, with a 30 year half-life, produced during nuclear fission (i.e., the splitting of a nucleus into at least two other nuclei) of various isotopes of uranium, plutonium, and thorium. Cesium-137 decays by β decay that is shortly followed by the emission of a γ ray from its short lived decay product, barium-137m (the “m” indicates it is a metastable nuclear isomer that decays very quickly). Two other isotopes of cesium, cesium-135 and cesium-134, are often considered less of a health concern because of their decay characteristics. For example, cesium-135, a β emitter, with a half-life of 2.3 million years has very low specific activity (i.e., number of decays per unit mass or volume). Cesium-134, a β emitter, has a half-life of 2.1 years so does not persist in the environment as long as cesium-137. However, determining cesium-137/cesium-134 ratios may help to identify the source and age of cesium in water.
A Series of Unfortunate Events
Alan Perkins in Life and Death Rays, 2021
The total release of radioactive substances was considered to be greater than 14 exabecquerels (EBq, 14 × 1018 Bq), which included 1.8 EBq of iodine-131, 0.085 EBq of caesium-137 and other caesium radionuclides, 0.01EBq of strontium-90 and 0.003 EBq of plutonium radionuclides. The dispersal of iodine-131 presented an immediate problem to the local population. All 45,000 residents of the power plant town of Pripyat were evacuated on April 27. By May 14, around 116,000 people who had been living within a 30-kilometre radius had been evacuated and relocated. About 1,000 of these residents returned unofficially to live in the contaminated zone preferring to live in their own homes despite the health risks. Most of those evacuated individuals received radiation doses of less than 50 mSv, although a few received 100 mSv or more. Large areas of Europe were affected and an area of more than 200,000 square kilometres was contaminated with caesium-137. The three most affected countries were Belarus, the Russian Federation and Ukraine, but the contamination affected countries throughout Europe. After the initial period, caesium-137 became the nuclide of greatest radiological importance. Ground deposition was strongly influenced by the prevailing winds and rainfall, but the end result was that sheep in highland areas as far away as Wales had consumed grass contaminated with caesium-137 and farmers were prohibited from selling their lamb at food markets for many weeks after the incident.
Cervical cancer
Pat Price, Karol Sikora in Treatment of Cancer, 2014
There is an ongoing debate about the optimal schedule for intrauterine brachytherapy.49 Low dose rate (LDR) systems with Caesium-137 were radiobiologically ideal as they allowed ongoing repair of radiation damage to normal tissues. However, these machines are no longer manufactured and are being replaced by high dose rate (HDR) systems delivering rates in excess of 1 Gy/min, and the most common source is Iridium-192. The short treatment time allows more geometrical stability of the applicator during treatment and more rapid patient throughput, but there is considerably less time for repair of radiation damage. Therefore, such treatments are fractionated over several days and the dose is adjusted for this difference in dose rate. Pulsed dose rate brachytherapy (PDR) uses an HDR source but delivers multiple small fractions over 2 days for a single insertion to reproduce LDR radiobiology.50 To be able to compare outcomes for these different dose rates and fractionation regimens it is now standard to report 2 Gy equivalent (EQD2) total doses.
Assessment of probable scenarios of radiological emergency and their consequences
Published in International Journal of Radiation Biology, 2020
Yehoshua Socol, Yuriy Gofman, Moshe Yanovskiy, Binyamin Brosh
According to IAEA (1987), the typical activity of a fresh Cs-137 radiation source for radiation therapy (RT) is 0.1 PBq (1014 Bq) or 3000 curie (Ci). Such sources are potentially dangerous with their activity significantly above D-values. D-value is that quantity of radioactive material, which, if uncontrolled, could result in the death or a permanent injury (IAEA 2006, p. 1). The corresponding D-values for Cs-137 are 1011 Bq if the source is not dispersed, and 2.0 × 1013 Bq if dispersed (IAEA 2006, p. 7). Sources for industrial applications, such as flow meters, thickness gauges, and well-logging devices, are weaker. Actually, the use of Cs-137 in radiation therapy (RT) is declining, having been substituted by Co-60 sources and later by compact electron accelerators. Co-60 is metal and does not lend itself to easy handling. As for Cs-137 sources, they are typically 30-ml ampules containing rice-sized granules of cesium chloride CsCl which dissolves in water like table salt (IAEA 1987), so dispersing CsCl seems rather straightforward.
Design, synthesis and cholinesterase inhibitory properties of new oxazole benzylamine derivatives
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2020
Ivana Šagud, Nikolina Maček Hrvat, Ana Grgičević, Tena Čadež, Josipa Hodak, Milena Dragojević, Kornelija Lasić, Zrinka Kovarik, Irena Škorić
Using the reaction of N-alkylation on the previously synthesised trans-chloro-arylethenyloxazole 120, new trans-amino-5-arylethenyl-oxazole derivatives trans-2–18 were synthesised (Scheme 1) with an aim to add a new functional group at the end of the oxazole derivative that resembles acetylcholine, the substrate of cholinesterase. The Buchwald-Hartwig reaction21 was utilised with two catalysts and the reaction was optimised for best conditions to enhance the yield. Change of base was crucial for the optimisation of this reaction. Sodium tert-butoxide was previously used as a base but the dehalogenation of the starting material was observed. Caesium carbonate improved yield and conversion. Temperature, solvent and catalyst used were independently varied to give the best conversion. The best conditions found are given in Scheme 1. The catalysed N-alkylation reaction is a complex coupling reaction and it gave a vast array of yields. Some of the substrates were optimised to excellent yields, while in the example of others only moderate to low yields were obtained. There is still some room for optimisation in the future with additional catalysts but at this time this was sufficient.
The in vivo performance of a novel thermal accelerant agent used for augmentation of microwave energy delivery within biologic tissues during image-guided thermal ablation: a porcine study
Published in International Journal of Hyperthermia, 2018
William Keun Chan Park, Aaron Wilhelm Palmer Maxwell, Victoria Elizabeth Frank, Michael Patrick Primmer, Jarod Brian Paul, Scott Andrew Collins, Kara Anne Lombardo, Shaolei Lu, Tiffany Marie Borjeson, Grayson Luderman Baird, Damian Edward Dupuy
Our thermal accelerant agent is similar in mechanism, with increased free water content and higher molecular dipole moment leading to improved energy transmission and greater coagulative necrosis. Unlike saline, however – which can freely dispserse within soft tissues due to its low viscosity [32] – the thermal accelerant agent described herein demonstrates temperature-dependent biphasic properties, existing as a liquid at room temperature and a viscous gel at 37 °C. This behaviour improves localisation of TA within the intended region of treatment, which may improve energy deliver to the lesion of interest and minimise unwanted extension of the ablation zone into adjacent structures. Additionally, caesium chloride’s higher atomic number allows for improved intraprocedural visualisation compared with sodium chlorid when performing ablations using CT guidance.
Related Knowledge Centers
- Formate
- Potassium
- Radionuclide
- Solar Cell
- Toxicity
- Pollucite
- Caesium-137
- Nuclear Fission Product
- Emission Spectrum
- Half-Life