China
Africa
Explore chapters and articles related to this topic
Radiation Hazards
Published in Dag K. Brune, Christer Edling, Occupational Hazards in the Health Professions, 2020
Radiation exposure is inversely proportional to the square of the distance to the radiation source (“inverse square law”). For example, by increasing by a factor of two, the exposure is decreased by a factor of four. Although this reduction in exposure is exactly true only for point sources, the use of distance, especially in handling radioactive sources, will greatly reduce exposure. When transferring an unshielded radioactive vial, for example, the use of tongs or similar remote handling devices will reduce exposure significantly, particularly to the hands. If time and distance are not enough to reduce the radiation exposure, one has to shield the radiation source. Shielding involves positioning of an absorbing material between the source and the area where the exposure is measured (i.e., where the personnel will be located).
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
Radiation exposure may cause severe acute health effects and chronic carcinogenic, teratogenic, or mutagenic effects. The principle of as low as reasonably achievable (ALARA) is the basis for the management of nuclear waste originally established in the Atomic Energy Act of 1954. The hazardous nature of a waste stream is measured by a number of factors: 1. Activity level expressed as nanocuries/gram (nCi/g) of waste The type of radioactive emission: alpha, beta, gammaThe half-life of the waste isotopesThe relative physical stability of the wasteThe mobility, leachability, or in some cases volatility of the waste
Concerns with radiation safety
Published in Yi-Hwa Liu, Albert J. Sinusas, Hybrid Imaging in Cardiovascular Medicine, 2017
Mathew Mercuri, Andrew J. Einstein
The use of medical imaging has greatly improved our ability to accurately diagnose disease and manage patient care. However, as in all aspects of health care, it is important that the benefits of a procedure outweigh the risks involved. Whereas the benefits of medical imaging, while often difficult to quantify, are widely appreciated, optimizing this benefit-to-risk ratio requires that we know something about the risks involved. Most radiologic and all nuclear medicine procedures expose patients and operators to ionizing radiation. Radiation exposure can result in detrimental health effects, including skin injury, genetic defects, and cancer. Thus, it is important that physicians both avoid inappropriate procedures and limit exposure to levels that are “as low as reasonably achievable” (ALARA principle) (International Commission on Radiological Protection [ICRP] 103, 2007).
Investigation of the gamma photon shielding in Se–Te–Ag chalcogenide glasses using the Phy-X/PSD software
Published in Cogent Engineering, 2022
Fatemah. H. Alkallas, Amira Ben Gouider Trabelsi, Samira Elaissi, Tahani A. Alrebdi, Lamia Abu El Maati, Fatma. B. M. Ahmed, M. M. Mahasen, M. Ahmad, M. M. Soraya
Protecting the environment and people from harmful radiation has become the focus of considerable research. Several attempts have been made to control and reduce harmful radiation exposure through radiation shielding. Developing cheap and easy-to-process shielding materials that can offer reliable protection against the harmful effect of radiations has become essential. For many years, lead (Pb) has been used in different shielding applications attributed to its hardness, low cost, and good capability to protect against ionizing radiations as explained in previous works of AbuAlRoos et al. (2019) and Al-Buriahi, El-Agawany et al. (2020). However, the use of lead has been recently limited because of its toxicity, which has forced many researchers to find alternative shielding materials as Al-Hadeethi et al. (2020), Hsiao et al. (2011), Ogawa et al. (2008), and Hulbert and Carlson (2009). Concrete and rocks are the most commonly used materials in shielding. Also, Al-Buriahi and Singh (2020), Obaid, Gaikwad and Pawar (2018), Tekin and Kilicoglu (2020), and Akman et al. (2019), Obaid, Sayyed et al. (2018) and Al-Buriahi, Abouhaswa et al. (2020) have been suggested alloys and polymers as candidate materials for radiation shielding; however, they have several practical limitations and are not transparent.
Research on performance improvement measures for medical radiation shielding film through removal of air bubbles and pinholes
Published in Radiation Effects and Defects in Solids, 2021
Recently, additional measures to minimize medical radiation exposure are being implemented owing to the increasing use of general radiography and computed tomography scanning in hospitals (1). Reducing medical radiation exposure affects the safety of healthcare professionals and the safety of patients, and the scope of radiation shielding applications is wide. Scattering rays, which correspond to low-dose radiation, have the greatest impact on medical radiation exposure of healthcare workers and patients. Low-dose radiation, such as natural radiation, is generally defined as that at dosages less than 100 mSv (2,3). Current epidemiological studies have failed to provide evidence of cancer incidences upon radiation exposure below 100 mSv. However, based on the linear proportionality theory without thresholds in BEIR VII, low-dose radiation leads to cancer and genetic disorders. Therefore, low-dose radiation should be controlled using shielding equipment through justification and optimization (4–9).
Comparing the Effectiveness of Polymer and Composite Materials to Aluminum for Extended Deep Space Travel
Published in Nuclear Technology, 2020
Daniel K. Bond, Braden Goddard, Robert C. Singleterry, Sama Bilbao y León
Materials for crewed, deep space missions have primary purposes as fuels, walls, pipes, racks, storage, etc. Each must also satisfy their secondary purpose of radiation protection, shielding astronauts from the two primary sources of space radiation: galactic cosmic rays (GCRs) and solar particle events (SPEs). GCRs, which are composed of highly energetic and fully ionized elements, are a chronic source of radiation exposure and account for the majority of the background radiation. SPEs, which originate from coronal mass ejections (CMEs), are composed of mostly protons. Since SPEs are sporadic and vary in magnitude, composition, and duration, they have the potential to pose an acute risk. The effect of radiation exposure, which varies depending on the source, intensity, and duration of exposure, ranges from nausea and vomiting to cancer and death.1