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Radionuclide Production
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
With the ‘Big Bang’, the cosmic explosion about 14 billion years ago, the process to create all matter started. Particles like protons and neutrons, which form the building blocks of nuclei, appeared as free particles during the first seconds. Various types of nuclear reactions formed different combinations of protons and neutrons to create light elements as 4He, 3He, and 7Li and later, in the stars, heavier elements. All matter around us was created in nuclear reactions as a mixture of stable and unstable (radioactive) combinations of protons and neutrons. Over time, the unstable combinations have undergone transformation (radioactive decay) to form stable combinations but some with exceptionally long half-lives (natural radioactivity) remain, potassium-40, lead-204, thorium-232 and the natural occurring isotopes of uranium. Some of these and their radioactive daughters were early applied in biology and medicine.
Radiation injuries
Published in Jan de Boer, Marcel Dubouloz, Handbook of Disaster Medicine, 2020
Yves Jouchoux, Christophe Boyer
Natural background radioactivity. The natural exposure of human beings to radioactivity is equivalent to 2mSv per year. The main source is radon 222 (a natural gas absorbed by inhalation). The irradiation increases in those areas that are rich in granite rocks. Other external sources from natural elements are uranium 238 and thorium 232. Internal sources include potassium 40. Natural external irradiation originates also from cosmic radiation from outside the Earth: this irradiation is greater at higher altitudes than at sea level (for example, in air travel, the irradiation dose is about 100 times greater).
Micronutrients in Protecting Against Late Adverse Health-Effects of Diagnostic Radiation Doses
Published in Kedar N. Prasad, Micronutrients in Health and Disease, 2019
Several radioactive isotopes of varying physical half-lives are found on the earth. They include radioactive potassium (40K, with a half-life of 1.28 billion years, emits both beta-and gamma-radiation) and radioactive rubidium (87Rb with a half-life of 4.7 billion years, emits only beta-emitter), and alpha-radiation emitters naturally occurring isotopes 238U with a half-life of 4.7 billion years, 235U with a physical half-life of about 700 million years, and 232Th with a half-life of 14.05 billion years.
Markov chain Monte Carlo sampling for accurate estimation of spatial distribution of naturally occurring radionuclides radiation (232Th, 40K, and 238U) in Senegal
Published in Egyptian Journal of Basic and Applied Sciences, 2020
Djicknack Dione, Modou Mbaye, Cheikh Amadou Bamba Dath, Ababacar Sadikhe Ndao, Ndeye Arame Boye Faye
A high resolution, 1024 channels portative gamma spectrometer with a large (103 cm3) high-density Bismuth Germanate crystal detector with an energy range from 30 KeV to 3000 KeV was used for field measurement. The sampling Measurement time was set around 5 minutes for each individual point in a pseudo-randomly sampling procedure. A Bluetooth GPS device paired with the spectrometer was used to record the geographical position. The gamma-ray spectra recorded for each point were further analyzed and taking into account transition of interest from well-defined photo peak from natural radioisotopes of 40K, 232Th and 238U. Determination of the primordial potassium 40K in soil was through the detection of 1460 KeV of associated with the gamma-ray decay of 40K. Based on the assumption of secular equilibrium of naturally occurring radioisotopes of 232Th and 238U primordial series; the thorium radioisotope was estimated through the detection of 2615 KeV gamma-ray energy of 208TI; similarly, 238U was estimated through detection of 1765 KeV gamma-ray energy of 214Bi. An assumption of equilibrium of primordial radionuclides is common in rocks and the 232Th series may be considered in equilibrium in most geological environments [15]. The activity concentration of radioisotopes was converted into specific concentration according to the following relation given by IAEA-2003. Figure 1 shows the geographic location of the study area. The study area is characterized by cumulative rain between 1100 and 1500 mm in the time between 2015 and 2016. Local temperature varies substantially between 19°C and 45°C. In this site of Saraya, measurement of six fields were carried out.