Radon , 1924 Radon is a naturally occurring radioactive
noble gas discovered in 1900 by
Friedrich Ernst Dorn (1848-1916) and is considered
carcinogenic. Radon is increasingly found in areas with high levels of
uranium and
thorium in the soil. These are mainly areas with high
granitic rock deposits. According to studies by the
World Health Organization, the incidence of
lung cancer increases significantly at radiation levels of 100-200
Bq per cubic meter of indoor air. The likelihood of developing lung cancer increases by 10% with each additional 100 Bq/m3 of indoor air. Elevated radon levels have been measured in numerous areas in Germany, particularly in southern Germany, Austria and Switzerland.
Germany The Federal Office for Radiation Protection has developed a radon map of Germany. The EU Directive 2013/59/Euratom (Radiation Protection Basic Standards Directive) introduced
reference levels and the possibility for workers to have their workplace tested for radon exposure. In Germany, it was implemented in the Radiation Protection Act (Chapter 2 or Sections 124-132 StrlSchG) and the amended Radiation Protection Ordinance (Part 4 Chapter 1, Sections 153-158 StrlSchV). The new radon protection regulations for workplaces and new residential buildings have been binding since January 2019. Extensive radon contamination and radon precautionary areas have been determined by the ministries of the environment of the federal states (as of June 15, 2021).
Austria The highest radon concentrations in Austria were measured in 1991 in the municipality of Umhausen in Tyrol. Umhausen has about 2300 inhabitants and is located in the Ötztal valley. Some of the houses there were built on a bedrock of
granite gneiss. From this porous
subsoil, the radon present in the rock seeped freely into the unsealed cellars, which were contaminated with up to 60,000 Becquerels of radon per cubic meter of air. Radon levels in the apartments in Umhausen have been systematically monitored since 1992. Since then, extensive radon mitigation measures have been implemented in the buildings: New buildings, sealing of cellar floors, forced ventilation of cellars or relocation. Queries in the
Austrian Health Information System (
ÖGIS) have shown that the incidence of new cases of lung cancer has declined sharply since then. The Austrian National Radon Project (ÖNRAP) has studied radon exposure throughout the country. Austria also has a Radiation Protection Act as a legal basis. Indoor limits were set in 2008 The Austrian Ministry of the Environment states that In Austria, the Radon Protection Ordinance in its version of September 10, 2021 is currently in force, which also defines the radon protection areas and radon precautionary areas.
Switzerland The aim of the Radon Action Plan 2012-2020 in Switzerland was to incorporate the new international recommendations into the Swiss strategy for protection against radon and thus reduce the number of lung cancer cases attributable to radon in buildings. On 1 January 2018, the limit value of 1000 Bq/m3 was replaced by a reference value of 300 becquerels per cubic meter (Bq/m3) for the radon gas concentration averaged over a year in "rooms in which people regularly spend several hours a day". Subsequently, on May 11, 2020, the
Federal Office of Public Health FOPH issued the Radon Action Plan 2021-2030. The provisions on radon protection are primarily laid down in the Radiation Protection Ordinance (RPO).
Radiation sickness among miners In 1879,
Walther Hesse (1846-1911) and
Friedrich Hugo Härting published the study "Lung Cancer, the Miners' Disease in the Schneeberg Mines". Hesse, a
pathologist, was shocked by the poor health and young age of the miners. This particular form of
bronchial carcinoma was given the name
Schneeberg disease because it occurred among miners in the
Schneeberg mines (Saxon Erz Mountains). When Hesse's report was published, radioactive radiation and the existence of radon were unknown. It was not until 1898 that
Marie Curie-Skłodowska (1867-1934) and her husband
Pierre Curie (1859-1906) discovered radium and created the concept of
radioactivity. Beginning in the fall of 1898, Marie Curie suffered from inflammation of the fingertips, the first known symptoms of
radiation sickness. In the
Jáchymov mines, where silver and
non-ferrous metals were mined from the 16th to the 19th century,
uranium ore was mined in abundance in the 20th century. It was only during the
Second World War that restrictions were imposed on ore mining in the Schneeberg and Jáchymov mines. After World War II,
uranium mining was accelerated for the
Soviet atomic bomb project and the emerging Soviet
nuclear industry. Forced labor was used. Initially, these were German prisoners of war and displaced persons, and after the
February Revolution of 1948, political prisoners were imprisoned by the
Communist Party regime in Czechoslovakia, as well as conscripted civilian workers. Several "Czechoslovak
gulags" were established in the area to house these workers. In all, about 100,000 political prisoners and more than 250,000 forced laborers passed through the camps. About half of them probably did not survive the mining work. Uranium mining ceased in 1964. We can only speculate about other victims who died as a result of radiation. Radon-bearing springs discovered during the mining in the early 20th century established a spa industry that is still important today, as well as the town's status as the oldest radium brine spa in the world.
Wismut AG The approximately 200,000 uranium miners employed by
Wismut AG in the former Soviet occupation zone of East Germany were exposed to very high levels of radiation, particularly between 1946 and 1955, but also in later years. This exposure was caused by the inhalation of radon and its radioactive by-products, which were deposited to a considerable extent in the inhaled dust. Radiation exposure was expressed in the historical unit of
working level month (WLM). This unit of measurement was introduced in the 1950s specifically for occupational safety in
uranium mines in the U.S. to record radiation exposure resulting from radioactive exposure to radon and its decay products in the air we breathe. Approximately 9000 workers at Wismut AG have been diagnosed with lung cancer.
Radium Until the 1930s, radium compounds were not only considered relatively harmless, but also beneficial to health, and were advertised as medicines for a variety of ailments or used in products that glowed in the dark. Processing took place without any safeguards. Until the 1960s, radioactivity was often handled naively and carelessly. From 1940 to 1945, the Berlin-based
Auergesellschaft, founded by
Carl Auer von Welsbach (1858-1929,
Osram), produced a
radioactive toothpaste called
Doramad that contained
thorium-X and was sold internationally. It was advertised with the statement, "Its radioactive radiation strengthens the defenses of the teeth and gums. The
cells are charged with new life energy and the destructive effect of
bacteria is inhibited. This gave the claim of
radiant white teeth a double meaning. By 1930, there were also bath additives and
eczema ointments under the brand name "Thorium-X". Radium was also added to toothpastes, such as
Kolynos toothpaste. After World War I, radioactivity became a symbol of modern achievement and was considered "chic". Radioactive substances were added to mineral water, condoms, and cosmetic powders. Even chocolate laced with radium was sold. The toy manufacturer
Märklin in the Swabian town of Göppingen tested the sale of an X-ray machine for children. At upper-class parties, people "photographed" each other's bones for fun. A system called
Trycho () for
epilation (hair removal) of the face and body was
franchised in the USA. As a result, thousands of women suffered skin burns,
ulcers and tumors. A radium industry developed, using radium in creams, beverages, chocolates, toothpastes, and soaps. It took a relatively long time for radium and its decay product radon to be recognized as the cause of the observed effects.
Radithor, a radioactive agent consisting of triple-
distilled water in which the radium
isotopes 226Ra and 228Ra were dissolved so that it had an
activity of at least one
microcurie, was marketed in the United States. It was not until 1932, when the prominent American athlete
Eben Byers, who by his own account had taken about 1,400 vials of Radithor as medicine on the recommendation of his physician, fell seriously ill with cancer, lost many of his teeth, and died shortly thereafter in great agony, that strong doubts were raised about the healing powers of Radithor and radium water.
Radium cures 1908 saw a boom in the use of radioactive water for therapeutic purposes. The discovery of springs in Oberschlema and
Bad Brambach paved the way for the establishment of radium spas, which relied on the healing properties of radium. During the cures, people bathed in radium water, drank cures with radium water, and inhaled radon in emanatoriums. The baths were visited by tens of thousands of people every year, hoping for
hormesis. To this day, therapeutic applications are carried out in spas and healing tunnels. The natural release of radon from the ground is used. According to the German Spa Association, the activity in water must be at least 666 Bq/liter. The requirement for inhalation treatments is at least 37,000 Bq/m3 of air. This form of therapy is not scientifically accepted and the potential risk of radiation exposure is criticized. The equivalent dose of a radon cure in Germany is given by the individual health resorts as about one to two millisieverts, depending on the location. In 2010, doctors in Erlangen, using the (outdated)
LNT (Linear, No-Threshold) model, concluded that five percent of all lung cancer deaths in Germany are caused by radon. There are radon baths in
Bad Gastein,
Bad Hofgastein and
Bad Zell in Austria, in
Niška Banja in Serbia, in the radon revitalization bath in
Menzenschwand and in
Bad Brambach,
Bad Münster am
Stein-Ebernburg,
Bad Schlema,
Bad Steben,
Bad Schmiedeberg and
Sibyllenbad in Germany, in
Jáchymov in the Czech Republic, in
Hévíz in Hungary, in
Świeradów-Zdrój (Bad Flinsberg) in Poland, in Naretschen and
Kostenez in Bulgaria and on the island of
Ischia in Italy. There are radon tunnels in
Bad Kreuznach and
Bad Gastein.
Illuminated dials The dangers of radium were recognized in the early 1920s and first described in 1924 by New York dentist and oral surgeon Theodor Blum (1883-1962). He was particularly aware of the use of radium in the watch industry, where it was used for luminous dials. He published an article on the clinical picture of the so-called
radium jaw. He observed this disease in female patients who, as dial painters, came into contact with luminous paint whose composition was similar to Radiomir, a luminous material invented in 1914 consisting of a mixture of
zinc sulfide and
radium bromide. As they painted, they used their lips to form the tip of the phosphorus-laden brush into the desired pointed shape, and this is how the radioactive radium entered their bodies. In the U.S. and Canada alone, about 4,000 workers were affected over the years. In retrospect, the factory workers were called the
Radium Girls. They also played with the paint, painting their fingernails, teeth and faces. This made them glow at night to the surprise of their companions. , Paris After
Harrison Stanford Martland (1883-1954), chief medical examiner in
Essex County, detected the radioactive noble gas radon (a decay product of radium) in the breath of the Radium Girls, he turned to
Charles Norris (1867-1935) and
Alexander Oscar Gettler (1883-1968). In 1928, Gettler was able to detect a high concentration of radium in the bones of Amelia Maggia, one of the young women, even five years after her death. In 1931, a method was developed for determining radium dosage using a film dosimeter. A standard preparation is irradiated through a hardwood cube onto an X-ray film, which is then blackened. For a long time, the
cube minute was an important unit of radium dosage. It was calibrated by ionometric measurements. The radiologists
Hermann Georg Holthusen (1886-1971) and
Anna Hamann (1894-1969) found a calibration value of 0.045 r/min in 1932/1935. The calibration film receives the y-ray dose of 0.045 r per minute through the wooden cube from the preparation of 13.33 mg. In 1933, the physicist
Robley D. Evans (1907-1995) made the first measurements of radon and radium in the excretions of female workers. On this basis, the National Bureau of Standards, the predecessor to the
National Institute of Standards and Technology (NIST), set the limit for radium at 0.1
microcuries (about 3.7
kilobecquerels) in 1941. A
Radium Action Plan 2015-2019 aims to solve the problem of radiological contamination in Switzerland, mainly in the
Jura Mountains, due to the use of radium luminous paint in the watch industry until the 1960s. In France, a line of cosmetics called
Tho-Radia, which contained both thorium and radium, was created in 1932 and lasted until the 1960s.
Other terrestrial radiation Terrestrial radiation is the ubiquitous radiation on Earth caused by
radionuclides in the ground that were formed billions of years ago by stellar
nucleosynthesis and have not yet decayed due to their long
half-lives. Terrestrial radiation is caused by natural radionuclides that occur naturally in the Earth's soil, rocks,
hydrosphere, and
atmosphere. Natural radionuclides can be divided into
cosmogenic and
primordial nuclides. Cosmogenic nuclides do not contribute significantly to the terrestrial ambient radiation at the Earth's surface. The sources of terrestrial radiation are the natural radioactive nuclides found in the uppermost layers of the Earth, in the water and in the air. These include in particular •
Thorium-232 (half-life 14 billion years), •
Uranium-238 (half-life 4.4 billion years), •
Uranium-235 (half-life 0.7 billion years) and •
Potassium-40 (half-life 1.3 billion years).
Mining and extraction of fuels According to the
World Nuclear Association,
coal from all deposits contains traces of various radioactive substances, particularly radon, uranium and thorium. These substances are released during coal mining, especially from surface mines, through power plant emissions, or power plant ash, and contribute to terrestrial radiation exposure through their exposure pathways. In December 2009, it was revealed that
oil and
gas production generates millions of tons of radioactive waste each year, much of which is improperly disposed of without detection, including
226Radium and
210Polonium. The specific activity of the waste ranges from 0.1 to 15,000 becquerels per gram. In Germany, according to the
Radiation Protection Ordinance of 2001, the material is subject to monitoring at one Becquerel per gram and would have to be disposed of separately. The implementation of this regulation has been left to the industry, which has disposed of the waste carelessly and improperly for decades.
Building material Every building material contains traces of natural radioactive substances, especially 238uranium, 232thorium, and their decay products, and 40potassium. Solidified and effusive rocks such as
granite,
tuff, and
pumice have higher levels of radioactivity. In contrast, sand,
gravel,
limestone, and natural
gypsum (
calcium sulfate dihydrate) have low levels of radioactivity. The European Union's
Activity Concentration Index (ACI), developed in 1999, can be used to assess radiation exposure from building materials. It replaces the Leningrad summation formula, which was used in 1971 in Leningrad (St. Petersburg) to determine how much radiation exposure from building materials is permissible for humans. The ACI is calculated from the sum of the weighted activities of 40potassium, 226radium, and 232thorium. The
weighting takes into account the relative harmfulness to humans. According to official recommendations, building materials with a European ACI value greater than "1" should not be used in large quantities.
Glazes Uranium
pigments are used to color ceramic tiles with
uranium glazes (red, yellow, brown), where 2 mg of uranium per cm2 is allowed. Between 1900 and 1943, large quantities of uranium-containing ceramics were produced in the United States, as well as in Germany and Austria. It is estimated that between 1924 and 1943, 50-150
tons of
uranium (V,VI) oxide were used annually in the U.S. to produce uranium-containing glazes. In 1943, the U.S. government imposed a ban on the civilian use of uranium-containing substances, which remained in effect until 1958. Beginning in 1958, the U.S. government, and in 1969 the
United States Atomic Energy Commission, sold depleted uranium in the form of
uranium(VI) fluoride for civilian use. In Germany, uranium-glazed ceramics were produced by the
Rosenthal porcelain factory and were commercially available until the early 1980s. Uranium-glazed ceramics should only be used as collector's items and not for everyday use due to possible abrasion.
ODL measurement network The Federal Office for Radiation Protection's monitoring network measures natural radiation exposure through the local dose rate (ODL), expressed in microsieverts per hour (μSv/h). In Germany, the natural ODL ranges from approximately 0.05 to 0.18 μSv/h, depending on local conditions. The ODL monitoring network has been operational since 1973 and currently comprises 1800 fixed, automatically operating measuring points. Its primary function is to provide early warning for the rapid detection of increased radiation from radioactive substances in the air in Germany. Spectroscopic probes have been successfully utilized since 2008 to determine the contribution of artificial radionuclides in addition to the local dose rate, showcasing the network's advanced capabilities. In addition to the ODL monitoring network of the Federal Office for Radiation Protection, there are other federal monitoring networks at the
Federal Maritime and Hydrographic Agency and the
Federal Institute of Hydrology, which measure gamma radiation in water; the
German Meteorological Service measures air activity with aerosol samplers. To monitor
nuclear facilities, the relevant federal states operate their own ODL monitoring networks. The data from these monitoring networks are automatically fed into the
Integrated Measurement and Information System (IMIS), where they are used to analyze the current situation. Many countries operate their own ODL monitoring networks to protect the public. In Europe, these data are collected and published on the EURDEP platform of the
European Atomic Energy Community. The European monitoring networks are based on Articles 35 and 37 of the
Euratom Treaty.
Radionuclides in medicine Nuclear medicine is the use of open radionuclides for diagnostic and therapeutic purposes (
radionuclide therapy). It also includes the use of other radioactive substances and
nuclear physics techniques for functional and localization diagnostics.
George de Hevesy (1885-1966) lived as a lodger and in 1923 suspected that his landlady was offering him pudding that he had not eaten the following week. He mixed a small amount of a radioactive isotope into the leftovers. When she served him the pudding a week later, he was able to detect radioactivity in a sample of the casserole. When he showed this to his landlady, she immediately gave him notice. The method he used made him the
father of nuclear medicine. It became known as the
tracer method, which is still used today in nuclear medicine diagnostics. A small amount of a radioactive substance, its distribution in the organism, and its path through the human body can be tracked externally. This provides information about various
metabolic functions of the body. The continuous development of radionuclides has improved radiation protection. For example, the mercury compounds 203chloro-merodrin and 197chloro-merodrin were abandoned in the 1960s as substances were developed that allowed a higher
photon yield with less radiation exposure. Beta emitters such as 131I and 90Y are used in radionuclide therapy. In nuclear medicine diagnostics, the beta+ emitters 18F, 11C, 13N, and 15O are used as radioactive markers for tracers in
positron emission tomography (PET).
Radiopharmaceuticals (isotope-labeled drugs) are being developed on an ongoing basis. Radiopharmaceutical residues, such as empty application syringes and contaminated residues from the patient's toilet, shower and washing water, are collected in tanks and stored until they can be safely pumped into the sewer system. The storage time depends on the half-life and ranges from a few weeks to a few months, depending on the radionuclide. Since 2001, by of the
Radiation Protection Ordinance, the specific radioactivity in the waste containers has been recorded in release
measuring stations and the release time is calculated automatically. This requires measurements of the sample activity in Bq/g and the surface contamination in Bq/cm2. In addition, the behavior of the patients after their discharge from the clinic is prescribed. To protect personnel, syringe filling systems, borehole measurement stations for nuclide-specific measurement of low-activity, small volume individual samples, a lift system into the measurement chamber to reduce radiation exposure when handling highly active samples, probe measurement stations, ILP (isolated limb perfusion) measurement stations to monitor activity with one or more detectors during surgery and report leakage to the surgical
oncologist.
Radioiodine therapy Radioiodine Therapy (RIT) is a nuclear medicine procedure used to treat thyroid hyperfunction,
Graves' disease, thyroid enlargement, and certain forms of thyroid cancer. The radioactive
iodine isotope used is 131Iodine, a predominant
beta emitter with a half-life of eight days, which is only stored in thyroid cells in the human body. In 1942,
Saul Hertz (1905-1950) of the Massachusetts General Hospital and the physicist Arthur Roberts published their report on the first radioiodine therapy (1941) for Graves' disease, at that time still predominantly using the 130iodine isotope with a half-life of 12.4 hours. At the same time,
Joseph Gilbert Hamilton (1907-1957) and
John Hundale Lawrence (1904-1991) performed the first therapy with 131iodine, the isotope still used today. In Germany, the minimum length of stay is 48 hours. Discharge depends on the residual activity remaining in the body. In 1999, the limit for residual activity was raised. The dose rate may not exceed 3.5
μSv per hour at a distance of 2 meters from the patient, which means that a radiation exposure of 1 mSv may not be exceeded within one year at a distance of 2 meters. This corresponds to a residual activity of about 250
MBq. Similar regulations exist in Austria. In Switzerland, a maximum radiation exposure of 1 mSv per year and a maximum of 5 mSv per year for the patient's relatives may not be exceeded. After discharge following radioiodine therapy, a maximum dose rate of 5 μSv per hour at a distance of 1 meter is permitted, which corresponds to a residual activity of approximately 150 MBq. In the event of early discharge, the supervisory authority must be notified up to a dose rate of 17.5 μSv/h; above 17.5 μSv/h, permission must be obtained. If the patient is transferred to another ward, the responsible
radiation protection officer must ensure that appropriate radiation protection measures are taken there, e.g. that a temporary
control area is set up.
Scintigraphy Scintigraphy is a nuclear medicine procedure in which low-level radioactive substances are injected into the patient for diagnostic purposes. These include
bone scintigraphy,
thyroid scintigraphy,
octreotide scintigraphy, and, as a further development of the procedure, single photon emission computed tomography (SPECT). For example, 201Tl
thallium(I) chloride, technetium compounds (99mTc tracer, 99mtechnetium tetrofosmin), PET tracers (with radiation exposure of 1100 MBq each with 15O-water, 555 MBq with 13N
ammonia, or 1850 MBq with 82Rb
rubidium chloride) are used in myocardial scintigraphy to diagnose blood flow conditions and function of the heart muscle (myocardium). The examination with 74 MBq 201Thallium Chloride causes a radiation exposure of about 16 mSv (effective dose equivalent), the examination with 740 MBq 99mTechnetium-MIBI about 7 mSv. Metastable 99mTc is by far the most important nuclide used as a tracer in scintigraphy because of its short half-life, the 140
keV gamma radiation it emits, and its ability to bind to many active biomolecules. Most of this radiation is excreted after the examination. The remaining
99mTc decays rapidly to 99Tc with a half-life of 6 hours. This has a long half-life of 212,000 years and, because of the relatively weak beta radiation released during its decay, contributes only a small amount of additional radiation exposure over the remaining lifetime. In the United States alone, approximately seven million individual doses of 99mTc are administered each year for diagnostic purposes. To reduce radiation exposure, the
American Society of Nuclear Cardiology (ASNC) issued dosage recommendations in 2010. The effective dose is 2.4 mSv for 13N-ammonia, 2.5 mSv for 15O-water, 7 mSv for 18F-
fluorodeoxyglucose, and 13.5 mSv for 82Rb-rubidium chloride. Compliance with these recommendations is expected to reduce the average radiation exposure to = 9 mSv. The
Ordinance on Radioactive Drugs or Drugs Treated with Ionizing Radiation regulates the approval procedures for the marketability of radioactive drugs.
Brachytherapy Brachytherapy is used to place a sealed radioactive source inside or near the body to treat cancer, such as prostate cancer. Afterloading brachytherapy is often combined with
teletherapy, which is external radiation delivered from a greater distance than brachytherapy. It is not classified as a nuclear medicine procedure, although like nuclear medicine, it uses the radiation emitted by radionuclides. After initial interest in brachytherapy in the early 20th century, its use declined in the mid-20th century because of the radiation exposure to physicians from manual handling of the radiation sources. It was not until the development of remote-controlled afterloading systems and the use of new radiation sources in the 1950s and 1960s that the risk of unnecessary radiation exposure to physicians and patients was reduced. In the afterloading procedure, an empty, tubular applicator is inserted into the target volume (e.g., the
uterus) before the actual therapy and, after checking the position, loaded with a radioactive preparation. The preparation is located at the tip of a steel wire that is advanced and retracted step by step under computer control. After the pre-calculated time, the source is withdrawn into a safe and the applicator is removed. The procedure is used for breast cancer, bronchial carcinoma or oral floor carcinoma, among others.
Beta emitters such as 90Sr or 106Ru or 192Ir are used. As a precaution, patients undergoing permanent brachytherapy are advised not to hold small children immediately after treatment and not to be in the vicinity of pregnant women, since low-dose radioactive sources (seeds) remain in the body after treatment with permanent brachytherapy. This is to protect the particularly radiation-sensitive tissues of a fetus or infant.
Thorium as a drug and X-ray contrast agent Radioactive
thorium was used in the 1950s and 60s to treat tuberculosis and other benign diseases (including children), with serious consequences (see Peteosthor). A stabilized
suspension of
colloidal
thorium(IV) oxide, co-developed by
António Egas Moniz (1874-1954), was used from 1929 under the trade name
Thorotrast as an X-ray contrast agent for
angiography in several million patients worldwide until it was banned in the mid-1950s. It accumulates in the
reticulohistiocytic system and can lead to cancer due to locally increased radiation exposure. The same is true for
cholangiocarcinoma and
angiosarcoma of the liver, two rare liver cancers. Carcinomas of the
paranasal sinuses have also been described following administration of Thorotrast. Typical onset of disease is 30–35 years after exposure. The
biological half-life of Thorotrast is approximately 400 years. The largest study in this area was conducted in Germany in 2004 and showed a particularly high mortality rate among patients exposed in this way. The
median life expectancy over a seventy-year observation period was 14 years shorter than in the comparison group. == Nuclear weapons and nuclear energy ==