China
Africa
Explore chapters and articles related to this topic
Calibration and Traceability
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
A standard that represents a direct realization of the becquerel is termed a primary standard. How this realization is achieved is beyond the scope of this book, but it is sufficient to say that a primary standard represents the top metrological level of measurement in a country and usually represents the national standard for the country for that specific unit of measure. Standards that are not direct realizations of the becquerel, but which are instead calibrated against another (generally primary) standard, are termed secondary standards. Commercial sources purchased from source suppliers, as well as some single-dose radiopharmaceutical preparations, can be considered as secondary standards if they are calibrated in this way. While many NMIs and DIs hold both primary and secondary standards, it should be noted that some hold only secondary standards that are traceable to another country’s primary standard.
Radioactivity and radiation
Published in Alan Martin, Sam Harbison, Karen Beach, Peter Cole, An Introduction to Radiation Protection, 2018
Alan Martin, Sam Harbison, Karen Beach, Peter Cole
The becquerel is defined as one nuclear disintegration per second and, compared with the curie, it is a very small unit. In practice, most radioactive sources are much larger than the becquerel and the following multiplying prefixes are used to describe them: 1 becquerel (Bq) = 1 dps1 kilobecquerel (kBq) = 103 Bq = 103 dps1 megabecquerel (MBq) = 106 Bq = 106 dps1 gigabecquerel (GBq) = 109 Bq = 109 dps1 terabecquerel (TBq) = 1012 Bq = 1012 dps1 petabecquerel (PBq) = 1015 Bq = 1015 dps
Environmental Radioactivity and Radioecology
Published in Gaetano Licitra, Giovanni d'Amore, Mauro Magnoni, Physical Agents in the Environment and Workplace, 2018
The SI unit of measure of the activity corresponds to 1 disintegration per second and is called Becquerel (symbol: Bq), after the name of the discoverer of radioactivity. However, it is still used as the historical unit of measure of the activity, the Curie (symbol; Ci), after Marie Sklodovska Curie. This unit of measure is much larger than the Becquerel. It corresponds to the activity of 1 gram of radium (radioisotope 226Ra). The following relationship holds between the two units: 1 Ci = 3.7 · 1010 Bq.
Cohort profile – MSK radiation workers: a feasibility study to establish a deceased worker sub-cohort as part of a multicenter medical radiation worker component in the million person study of low-dose radiation health effects
Published in International Journal of Radiation Biology, 2022
Lawrence T. Dauer, Meghan Woods, Daniel Miodownik, Brian Serencsits, Brian Quinn, Michael Bellamy, Craig Yoder, Xiaolin Liang, John D. Boice, Jonine Bernstein
Memorial Sloan Kettering Cancer Center (MSK) consisting of Memorial Hospital (MH) and the Sloan Kettering Institute (SKI) laboratories has a unique history with regard to the use of radiation for the diagnostic and therapeutic treatment of cancer and allied diseases. The initial New York Cancer Hospital (NYCH) was founded in 1884, barely a decade before the seminal burst of discoveries in radiation. Wilhelm Roentgen discovers ‘X-Rays’ in 1895 and a week later makes his famous first X-ray images of the hand of Mrs. Roentgen (Anna Bertha Ludwig) wearing her wedding ring (Pietzch 2018). Henri Becquerel subsequently discovered ‘radioactivity’ and radioactive materials in 1896 and this was quickly followed by the discovery of ‘polonium’ and ‘radium’ by the Curies (Nobel 2018). Immediate attention is given to the application of these rays and materials to the healing arts. Research and use began almost immediately across the world, even in New York where Thomas Edison demonstrated fluoroscopes in 1896 (King 2012). As early as 1902, the NYCH employed X-Rays and X-ray therapies, practices that continue through the present. Also, as early as 1902, several adverse biological effects began to be identified in some medical radiation workers, both short-term (e.g. reddening of the skin, dermatitis, skin ulceration, epilation, eye irritation) and longer-term (e.g. skin cancers, cataracts, and other cancers) (Linet et al. 2010).
Cost of fear and radiation protection actions: Washington County, Utah and Fukushima, Japan {Comparing case histories}
Published in International Journal of Radiation Biology, 2020
Bruce W. Church, Antone L. Brooks
For the NTS offsite public, which included Washington County, the radiation exposure guides/standards in the early 1950’s, were 3.9 R/series, which represents approximately 39 mSv/y (Shipman 1952; Collison 1953; Dunning 1955). In comparison, the radiation exposure reference guides used in Fukushima were set at 1–20 mSv/y (Urabe 2014). According to Urabe et al., ‘the people tended to request the lowest level of the reference level recommended by the ICRP for protective actions in the existing exposure situation’. This change in standards and public perception (fear) could, in large part, be the cause of the very different actions taken following each event. The units used and the expression of dose to measure these exposures were different. Thus, it is important to convert the units used in St. George; Roentgens (exposure), Curies (activity), Rad, and Rem (dose), to the international units used in Fukushima; Becquerel (activity), Grays, and Sieverts (dose). Since both events were the result of contamination with low LET radiation, beta gamma emitting radionuclides, especially 137Cs, it is possible to directly convert the units and make useful comparisons of the radiation exposures and doses. Since the reported doses were mostly from external gamma irradiation for both Utah and Japan, they are similar.
Radiation protection biology then and now
Published in International Journal of Radiation Biology, 2019
Andrzej Wojcik, Mats Harms-Ringdahl
The importance of Röntgen’s discovery for the field of medical diagnostics was realized immediately. By early 1896, X-rays started to be widely used for probing the human body (Rowland 1896; Roberts 1897; Farmelo 1995). There was no reason to assume that radiation exposure was associated with any harm. Indeed, how could harm arise from an agent that could not be appreciated by the senses? X-rays were regarded as ‘invisible light’, a concept created by Röntgen himself, who tested it by looking directly into the X-ray beam (Röntgen 1895). Moreover, radiation was proclaimed to be the source of energy which was responsible for driving biochemical reactions in the body. This belief was boosted by the discovery of radioactivity by Henrie Becquerel and Marie and Pierre Curie along with the recognition that waters in many health spas were radioactive (Macklis 1996).