The United States government began construction at Hanford in south central Washington State in 1943. Three nuclear reactors and two chemical processing plants were built and operated at Hanford during the Manhattan Project to develop nuclear weapons for use in World War II. The U.S. government retained private contractors including DuPont and General Electric to oversee the production of materials for nuclear weapons.

            Because of the war time pressure and inexperience with radioactive materials, the routine production of plutonium fuel for the reactors resulted in the release of large quantities of radioactive materials into the air, water and soil around the plants, including large amounts of iodine-131. Hanford did not install filters on the stacks of the plutonium processing plants until 1948. After 1948, Hanford continued to release radioactive materials and other hazardous chemicals into the air, soil and water including the Columbia River. By 1955, there were eight reactors in operation at Hanford. River water from the Columbia was used to cool these reactors and was contaminated with radioactivity, toxic chemicals and excessive heat.

            Over four billion gallons of contaminated liquids were released by Hanford operations. These releases contaminated over two hundred square miles of ground water under Hanford. In the 1960s Hanford began shutting down reactors and plants with the last plutonium plant and reactor being shut down in the late 1980s as a result of complaints by citizen action groups that the plants could not be operated safety without danger to the environment.

            In 1986, a release of millions of pages of Hanford documents by the U.S. Department of Energy revealed that over seventy five thousand square miles had been contaminated with radioactivity by Hanford’s operations. The Columbia River carried radioactivity as far as the Washington and Oregon coasts. Contaminated air from Hanford is thought to have traveled over Washington, Oregon, Idaho, Montana and parts of Canada.

            People who lived downwind from Hanford or who used water from the Columbia River downstream from Hanford were exposed to levels of radiation far above normal background levels from breathing contaminated air or consuming foods such as milk and cheese from cows and goats who grazed on contaminated vegetation. The contamination in the water of the Columbia River was concentrated in the fish and other aquatic life in the river. The waterfowl and other wildlife in the area which fed on the fish then became contaminated. The contaminated fish were especially injurious to the Native Americans who depend on the salmon in the Columbia River for their livelihood.

          Estimates of the number of people who may have had their health threatened by radioactivity released by Hanford over the past seventy years are as high as two million. The U.S. Department of Energy collaborated with the Hanford Health Information Network to educate the public on the dangers of radiation release from Hanford. Class action law suits have been working their way through the courts for years seeking compensations for health problems caused by Hanford radiation.

          The term “downwinders” refers to people, either individually or in communities, who have been exposed to radioactive materials as a result of nuclear fuel mining, nuclear weapons production and testing, nuclear waste disposal or nuclear accidents. The term derives from the fact that people who are downwind of an event that expels radioactive particles and gases into the atmosphere will be exposed to the fallout when the particles move through the air and fall to the ground. The common use of the term now includes radioactive contamination of ground water and the food chain as well as the atmosphere.

            Increased appearance of cancers, non-cancerous thyroid disease and congenital malformations have been documented in many communities that have been exposed to radioactive contamination from diverse sources. The Linear No-Threshold Model is used to estimated the exposure of individuals to radioactive contamination based on the amount of radiation and the length of exposure. Other demographic factors also have an impact on the way that radiation exposure affects the health of a particular community.

            Since 1945, there have been an estimated 2,000 nuclear devices exploded worldwide. The United States alone has exploded over 1,000 nuclear bombs. Up to 1980,  there were about 500 atmospheric nuclear tests conducted by the U.S, U.S.S.R. U.K., France and China with the U.S. accounting for over 300. Most of the U.S. tests took place in Nevada or the Pacific Proving Grounds in the Marshall Islands. However, tests have also been conducted in Alaska, Colorado, Mississippi and New Mexico.

          Nuclear explosions create the famous “mushroom cloud”. After the cloud reaches it maximum height, it begins to move downwind. Churning in the cloud spreads radioactive particles and gases throughout. Larger particles tend to settle near the site of the explosion while smaller particles and gases can be distributed across the world by the jet stream. Some clouds even reach the stratosphere and their radioactive materials may remain there for years until they finally fall to the ground.  While downwinder refers to someone near a nuclear event, in a very real sense, everyone in the world is downwind of nuclear fallout.

            Early in the Nuclear Age, the main concern about health risks of radioactive exposure centered on the fear that radiation would cause genetic damage and result in birth defects in the children of the people exposed. Subsequently it was found that the major risk was not genetic damage but damage to the health of the exposed people. Cancers that develop over the years following exposure are the main problem but there are also other types of tissue damage and illnesses resulting from radiation exposure.

            In 1963, many nuclear nations and other nations who did not yet have nuclear weapons signed the Limited Test Ban Treaty pledging to not test nuclear bombs in the atmosphere, underwater and in outer space.. The Soviet Union stopped testing in 1990, the U.K. stopped in 1991, the U.S. conducted its last underground test in 1992 and France and China stopped testing in 1996.  North Korea tested a nuclear device in 2009. In 1996, the United States and several other nuclear powers drew up the Comprehensive Test Ban Treaty (CTBT) in 1996. The Treaty will come into effect after all signatory countries file ratification documentation with the United Nations. To date, the United. States Congress has not ratified the CTBT.

          Shortly after the discovery of X rays in 1895, papers began appearing in scientific publications about the negative effects of high levels of exposure to such radiation. In the first year, suggestions about how to protect against ionizing radiation were made including the three main measures that are still emphasized today, limit the exposure to the shortest possible time, maintain as great a distance from the source as possible and employ shielding of some sort.

          In 1925 the First International Congress of Radiology was held in London, England. The issue of the need for a committee to consider protection against radiation was raised at the conference and, during the Second Congress in 1928, the International Commission on Radiological Protection (ICRP) was launched. 

         The ICRP is an independent international organization dedicated to radiological protection. It is a Registered Charity in the United Kingdoms and has a Scientific Secretariat in Ottawa, Canada.

          Currently, the ICRP has more than two hundred volunteers for thirty countries including some of the leading scientists and policy makers in the field of radiological protection. It is funded by contributions from organization interested in the work of the Commission.

          The structure of the Commission includes a Main Commission, a Scientific Secretariat, and five standing committees on effects, doses, medicine, applications and the environment.

          “ICRP is an independent, international organization that advances for the public benefit the science of radiological protection, in particular by providing recommendations and guidance on all aspects of protection against ionizing radiation. Since 1928, ICRP has developed, maintained, and elaborated the International System of Radiological Protection (ISRP) used world-wide as the common basis for radiological protection standards, legislation, guidelines, programs, and practice.

          The ISRP was developed based on the current scientific understanding of the biological effects of radiation exposure. In addition to the scientific aspects of the ISRP, the ICRP also takes into account ethical concerns, social expectations and knowledge gained in implementing the system.

           The ICRP regularly carries out consultation programs dealing with radiological exposure issues. Past projects included assessing radiation exposure and effects on astronauts, workers, cardiology patients and practitioners, patients being imaged, children being diagnosed and treated and people accidently exposed in radiotherapy. They also consulted on transfer of radionuclides from plants and animals, dangers of radon gas exposure, and potential problems with long term geological disposal of nuclear wastes.   

          The ICRP has published over a hundred documents on a wide range subjects concerning radiation protection including the reports generated by the consultation projects mentioned above. They also publish the documents that spell out their radiological protection system. They publish an annual report which is available online. Visitors to the website can download an extract from the 2007 Summary Recommendations, free posters for Pediatric radiology, free guides and explanatory notes, free education downloads and free educational CDs.

          In 2011 the ICRP held its First Symposium on the International System of Radiological Protection. The program and abstracts of the presented papers can be downloaded from the website. The Second Symposium will be held in 2013.

           After the Second World War, weapons research and work on civilian use of nuclear power were producing more and more radioactive materials. Scientists in the Manhattan Project had been assigned to work on what was then called “Health Physics.” A decade after the end of the war, the first conference on Health Physics was held at Ohio State University. One result of the conference was the formation of a professional Health Physics Society (HPS).

          Around 1960 with over a 1000 members, the Society formed “Sections” so each country with members in the HPS could have their own sub organization. In the mid 60s, a committee was formed within the HPS to work on the creation of a new international health physics association. Eventually, the committee was expanded to include 45 representatives from 25 countries. Articles of agreement were drafted, circulated and approved by the HPS. In 1965 the International Radiation Protection Association (IRPA) was formally launched with fifteen of the country subgroups participating. Over 1000 members were part of the new organization.  Currently there are 48 member societies on 5 continents. 37 of these member organizations have their own websites.

         “The primary purpose of IRPA is to provide a medium whereby those engaged in radiation protection activities in all countries may communicate more readily with each other and through this process advance radiation protection in many parts of the world. This includes relevant aspects of such branches of knowledge as science, medicine, engineering, technology and law, to provide for the protection of man and his environment from the hazards caused by radiation, and thereby to facilitate the safe use of medical, scientific, and industrial radiological practices for the benefit of mankind.”

          The first IRPA Congress was held in 1966 and IRPA congresses have been every 4 years since then. The Congresses cover wide ranges of topics and virtually any paper dealing with aspects of radiation protection is welcome. The Congresses are held all over the world and regional congresses are also sponsored.

          The IRPA publishes the proceedings of their conferences on their website. They have a large library of other documents available online on a host of radiation related topics. Of special note is a set of documents about a “radiation protection culture.”  These documents deal with how to go about creating a framework of behaviour in an organization that supports radiation protection. They also archive documents for other international organizations.

            The IRPA has an education program that assists in training radiation protection professionals to qualify as “Radiation Protection Experts (RPE).” This profession is listed in the International Standard Classification of Occupations which catalogs the areas of expertise associated with this profession. The IRPA is currently developing a certification process for RPEs.

            The IRPA website lists 5 governmental radiation organizations, 4 NGOs concerned with radiation, and 4 professional organizations with which the IRPA has links. There is a page of links for radiation protection related websites.

            The IRPA website is an excellent source of information for anyone concerned with radiation protection, especially anyone working in a related field.

           In 1988 the Radiation and Public Health Project (RPHP) was created by the United Church of Christ Commission for Racial Justice. Jay M. Gould and Benjamin A Goldman started the project as a spinoff of their work at Public Data Access, Inc. In 1995 RPHP became an independent non-profit 501(c)3 organization. The mission of the organization includes research, education and raising public awareness.

           RPHP research is focused on ”studying the links between low-level radiation and world-wide increases in diseases, especially cancer and those affecting the newborn and children  and to become the leading, world-wide source of information on radiation and public health issues.”

           The RPHP education efforts  “publishing the results of research dealing with the impact of low-level radiation on public health and disseminating this information to the public, media, policy makers and the scientific community. They have a section of their website where people can order from a dozen books and 10 monographs dealing with radiation related health issues. The RPHP published a newsletter between 1998 and 2010 which is available online. There is also a page on the website with a number articles on radiation issues from various sources.

           RPHP also works to increase public awareness by “promoting public awareness and responsible public policy related to radiation and public health, in the areas of freedom of information…objective medical and scientific investigation… institutional accountability…independent oversight…and responsible public health and environmental policy.” Their testing of nearly 5000 children’s teeth for strontium-90 showed a 50% rise in average levels with the highest levels near nuclear power plants . Tests of teeth from young cancer victims show higher Sr-90 that in health children. Similar tests are being carried out on teeth of Baby Boomers

           For fifty years there has been an increasing body of evidence that indicates a probable link between the ingestion of man-made low level radiation fission products and an increase in world-wide immune deficiency diseases such as cancer, especially affecting the newborn. RPHP has been collecting epidemiological evidence of this trend.

           The RPHP has published five books that summarize hundreds of publish peer reviewed articles dealing with the health impacts of man-made fission products during the Nuclear age. There is strong evidence that the very young have been adversely impacted by such fission products from infant mortality and low birth weight from published vital statistics especially during the atmospheric nuclear tests during the 50s and 60s.

           The RPHP has also traced damage to hormonal and immune systems on a decade by decade basis in the Baby Boomers born between 1945 and 1965. They have shown epidemic increases in infant cancer between the ages of 5 and 9 in children born in the 1950s.

           There was a 20 year decline in Scholastic Aptitude Test scores that began in 1963. The RPHP points out that 1963 is the year that children born in 1945, the first year of nuclear detonations and fallout, reached 18 and took the test. The test scores rose again after all children born during the 20 years of atmospheric tests passed the age of 18.

           The RPHP suggests that the civilian nuclear reactors that began coming on line came in the 1970s and released radioactive materials during normal operation and accidents may have caused an increase in immunodeficiency diseases including AID and early breast cancer. RPHP research has also shown a clear correlation between breast and prostate cancer mortality rates and proximity to nuclear power plants across the United States.

            Following the Fukushima nuclear disaster in March 11, 2011, a group of friends in the United States and Japan started a dialog to discuss what they could to help the friends and family in Japan. Since monitoring for radioactivity was very important following the disaster, the availability of Geiger counters was a critical issue. Seeing that conventional sources of Geiger counters sold out quickly after the disaster, the conversation turned to the possibility of building and distributing Geiger counter. People who had expertise in particular relevant areas were invited to join the conversation.

            Work began to aggregate and display radiation readings on an online map. As readings began to come in and were added to the map, areas with no readings were noted and it became a priority to get Geiger counters into those areas.

            An annual event in Japan for hardware hobbyists was converted into a conference on responses to the nuclear disaster following the Fukushima earthquake and tsunami. Some of the people working on the project met for the first time at the conference on April 1, 2012. One outcome of the conference was the design of a new Geiger counter which would come to be called bGeigi. It would incorporate a GPS which would allow it to be moved around to take radiation readings. It was decided that a organization would be created to focus on aggregating and displaying radiation data. The name Safecast was chosen for this new organization.

            Safecast proceeded to obtain funding from Kickstarter and private individuals. Hundreds of volunteers were recruited and Safecast became the organization to publish more information on radiation levels in Japan than any other institution.

            The main Geiger counter designed by Safecast and manufactured by International Medcom is called the Inspector Alert (IA). It is based around a 2” diameter pancake Geiger-Müller tube. This tube has excellent sensitivity for alpha, beta and gamma radiation. The IA is handheld and easy to use with a digital display. The units cost $700 each and forty have been built and deployed.

            The CRM 100 has a design similar to the IA but it employs a smaller and cheaper Geiger-Müller tube called the LND 712. It is smaller, cheaper, less sensitive and takes a little longer to register than the 2” tube in the IA. It is the device primarily distributed to volunteers who want to take individual readings around their homes and neighborhoods. It costs $450 and thirty units have been built and deployed.

            The bGeigie is basically a IA combined with a GPS and electronics which takes a reading every five seconds with a GPS tag and stores it to an SD care. The bGeigie is placed in a weatherproof box and attached to a car so it can be moved around and automatically take readings over a wide area. Wifi has been added to the most recent design to allow readings to be uploaded in real time. It costs $1000 and twenty five have been built and distributed.

            The nGeigie has the 2” Geiger-Müller tube and is intended to be set up at a fixed location to take repeated readings. Wifi and wireless versions will be available as installation requirements dictate. Safecast is establishing a fixed sensor network based on the nGeigie. It costs $500 and twenty have been built and distributed.

            The iGeigie is a design concept that is intended to work with a mobile device such as an iPhone. It is still in the prototype stage. When manufactured, it will cost $200.

            The Safecast map displays over two million data points, primarily over Japan. There is a Fusion map that has been created which uses Google Fusion table to display data on Google maps. An Interpolation map has been create which attempts to uses shading to filling in the estimated radiation between collection points. An Aggregate Feed map combines and displays radiation data from the Japanese government, several non-governmental organization as well as Safecast submissions. Safecast Drive maps display individual maps for each measurement drive by a Safecast volunteer. Yahoo! Japan has built a Yahoo map that shows data from fixed location Safecast sensors. In addition to these maps, Yahoo also uses the same data as the Yahoo map to show graphs of radiation.

Safecast map:

            Back in the 1950s at the height of the cold war, there was a great deal of talk about fallout shelters. When people were very serious about the prospect of nuclear war with the Russians and the Chinese, shelters were built that were intended to allow people to survive if their city was hit by a nuclear blast and they were outside the radius of immediate destruction. As international relations changed with détente and the fall of the Soviet Union as well as talk about nuclear winter following a nuclear war, interest in fallout shelters faded. Now with the Fukushima disaster and the continuing threat of the collapse of Fukushima Unit 4 spent fuel pool threatening the entire northern hemisphere, fallout shelters are a topic of interest once more.

            The first consideration for a fallout shelter is to put it underground. This provides additional protection against radiation as well as protecting against the effects of a nearby blast. The walls, ceiling and floor should be as thick and dense as possible and should be sealed against ground water and atmosphere. Including lead shielding in the shell of the shelter would increase radiation protection. The shelter should have a thick shielded door that is air tight and can be barred. Electromagnetic shielding in the form of a copper mesh would be a good addition to protect your electronics against the electromagnetic pulse the will accompany any nuclear blast.

            The first thing that the people in the shelter will need is a supply of air. It would be possible to store some oxygen and to have a way to remove carbon dioxide for a short period but impractical for more than a few days. For long term occupation, it will be necessary to have an air intake with a filtration system that can remove any radioactive particles in the incoming air. A heat exchanger would be a good addition to the system so that if the climate is cold, heat will not be lost when the air in the shelter is exhausted to the outside.

            Water will be the next concern. The municipal water supply may be shut off so the shelter should contain as much bottled water as possible. To provide for the possibility that piped water is still flowing, the shelter should also have a high level water filter that can remove particles down to 1 micron. Disposing of waste water and sewage is another issue. Chemical toilets or composting toilets will need to be installed with sufficient supplies and ventilation as required.

            After air and water comes food. Freeze dried foods store well and take up much less space than canned goods. Care must be taken to provide for a balanced diet for everyone who may take refuge in the shelter. Food that can be eater cold is preferable to food that must be cooked and will require some sort of heat source.

            The shelter will require energy to operate. Being underground will reduce the need for heat but you will still need to have some heating. You will need to have a radio that receives AM, FM and shortwave frequencies and that can transmit on shortwave bands. Antennas will be a problem if the destruction above ground is serious but you could have a buried extendable antenna to deal with this possibility.

            Boredom will be a real danger so the shelter should include reading material. If you have functioning electronics,  you will be able to store hundreds of books, movies and hours of music on compact electronic media. Multiplayer board and card games should be available as well.

            Basic furniture such as tables, chairs, beds, etc. will be required as well as changes of comfortable and easy to care for clothing. Computers would be useful for a number of purposes. Back-ups such as flashlights, radios, lamps, etc. should have a supply of rechargeable batteries. Some sort of exercise equipment such as a stationary bike should be included for exercise and could be hooked to a charge to recharge batteries.

            Studies have shown that colors of rooms and accessories can have positive or adverse psychological effects so attention should be paid to what colors you use to paint the interior of the shelter. Lighting should be natural solar spectrum LED or incandescent. You should include HEPA air filters for the air inside the shelter to remove any air particles that might carry disease or trigger allergies.

            Although there is a danger of rogue states and terrorists exploding a nuclear device in an American city, the old danger of an all out nuclear war seems remote. Such a war would probably render the earth uninhabitable so a fallout shelter would temporary protection at best. As must be obvious, all of these preparations will cost a great deal of time and effort. It is a matter of personal concern and resources as to whether or not you should build a fallout shelter.

 

            If there is a nuclear accident or explosion and radioactive fallout may reach your area, there are preparations that you can make to protect yourself and your family from the fallout. Time being one of the factors that reduces the danger of fall out, here are some temporary measures that will protect your home and family for a few days. These actions will take time to prepare so in order to be effective, they must be done well before any accident or explosion occurs. Since it is impossible to predict exactly when an accident or explosion will happen, it would be best to start working on them as soon as possible.

            Purchase a Geiger counter. You need to be able to monitor the radiation in your home in order to know if there is a problem and if your precautions are working. Inexpensive handheld Geiger counters are widely available for under five hundred dollars.

            The main concern is to prevent the radiation from getting into your home. Alpha particles are dangerous if inhale, eaten or they contact your skin but they can be blocked by as little as a sheet of paper or regular clothing. Beta particles require more shielding but they are not as damaging as alpha particles. The walls of your home and heavy drapes or curtains over the windows will stop beta particles. Unfortunately, gamma radiation requires thick shielding with dense materials such as lead.

            The main way to protect yourself and your family against radioactive fallout is to prevent it from entering your home. Purchase enough plastic sheeting used by painters to cover every entrance into your home. Get a lot of the blue painters masking tape as well. Measure and cut pieces of the plastic to fit over every single opening in the walls of your home including doors, windows, heater vents, air conditioning vents, wall outlets, etc. Label each piece by room and location in room. Store the plastic pieces until they are needed. Figure on sealing as much of the house as possible to give you and your family as much oxygen as possible.

            Purchase potassium iodine tablets. These will only protect against thyroid cancer caused by radioactive iodine-131 but that is a real danger from some types of fallout and it is one concern that can be eliminated.

            You should plan on having enough bottled water for everyone for at least 3 days. Remember that you will need water for cooking and washing. The municipal water supply may be shut off or it may be contaminated so you can’t count on using tap water unless you have a filter than can take out any radioactive particles.

            You need enough food for everyone for at least 3 days. Food that is sealed and preserved for long storage is best. Also remember that electricity may be off so food that does not need to be cooked is best.

            You should rig some sort of area where people can put on and take off their outer garments if it is necessary to go outside. This will prevent any particles that have accumulated on their clothing and footwear while outside from being brought into the house.

            These preparations will protect you and your family through a short period of radioactive fallout. A future post will provide details of longer term protection.

 

 

            Radioresistance is defined as the ability of some organisms to survive in environments where there is a high level of radioactivity. There may be naturally occurring radiation from uranium ores or man-made radiation from nuclear bombs or nuclear accidents. After the Chernobyl accident in Ukraine, scientists were surprised to find that many species survived when the assumption was that the high level of radiation should have killed most of them.

            Research has shown that repeated exposure to small doses of radiation may stimulate biological changes that confer some resistance to larger doses of radiation. Biological self-repair mechanisms have time to repair damage if the doses of radiation are small and spread out over time. If a culture of cells is irradiated, set aside for a time and then exposed to another dose of radiation, fewer cells will die from the second exposure. Studies have shown this response in yeast, bacteria, protozoa, algae, plants and insects. Tests of cultures of mammal cells and human cells have also shown this effect. Suggested mechanisms are enhanced DNA repair, increased expression of some genes and increased levels of certain proteins in the nucleus and in the rest of the cell.

            It has been suggested that radioresistance can be inherited genetically from parent organisms. Experiments with the common fruit fly confirmed this possibility. Some cancers are resistant to radiation treatment.  It is unclear whether this resistance is an original property of the cancer cells themselves or may be induced by repeated exposures to radiation. When a cancer is irradiated, some of the cells will be killed. When those which survive reproduce, they may pass along any enhanced radiation resistance that they have to their offspring. The next time the cancer is exposed to radiation, more of the cells will survive and so on.

            One way to compare the radioresistance of different organisms is with a comparison of what is called the median lethal dose. The median lethal dose is similar to the half-life of a radioactive material. When applied to radiation damage, It is the amount of radiation measured in Grays that will kill half of the organisms in a group in a specified period of time.  Here is a list of the amount radiation that will kill half of the corresponding group in thirty days.

Dog –                                         3.5 Grays

Human –                       4.5 Grays

Rat –                               7.5 Grays

Rabbit –                         8    Grays

Goldfish –                    20    Grays

German cockroach-   64    Grays

Shellfish-                   200    Grays

 

            As the chart indicates, generally, the higher up the evolutionary ladder, the more susceptible to radiation the organisms are. Greater complexity involves greater vulnerability to radiation damage.

            There is a theory called radiation hormesis that suggests that small doses of radiation just above the background level of radiation can stimulate the activation of biological protective biological mechanisms that could protect against some diseases. This theory is rejected by the U.S. National Council on Radiation Protection and Measurements and the United Nations Scientific Committee on the Effects of Atomic Radiation. These organizations hold to the linear no-threshold model which states that any exposure to any level of radiation can cause biological damage.

 

Ionizing radiation damages DNA in living cells. All cells have DNA repair machinery. If there is a way to accelerate the repair of DNA, it would confer some protection against the damage caused by ionizing radiation.

Some of the DNA in the nucleus of human cells contains the instructions for creating proteins which are the working machinery of all living cells. Some of these proteins carry out the repair of DNA. There is a human gene called RAD52 which carries the code for a protein also called RAD52. This protein binds the ends of single strand DNA and also facilitates the coming together of complimentary DNA strands to create the famous double helix of DNA. It also interacts with the RAD51 protein which is involved in DNA recombination and repair.

Dealing with breaks in double stranded DNA is carried out by multiple repair mechanisms including a process called homologous recombination. Homologous recombination cuts out the damaged sections and inserts new sections created by copying the corresponding sections of undamaged DNA strands.

RAD52 had previously been shown to be involved in homologous recombination processes in yeast cells to repair radiation damage. Research in 1995 showed that causing the overexpression of the RAD52 gene in cultured monkey cells accelerated the homologous recombinant repair of DNA damaged by gamma rays. The RAD52 protein does not initiate the repair process but is involved in intermediate stages of repair through interaction with other mechanisms such as the RAD51 protein. When there is damage to the DNA of a cell, the RAD52 protein gathers at the site of the breaks in the strands. RAD52 fused with a fluorescent protein has been used as a marker of DNA damage and repair.

Multiplying copies of a gene will cause can be used to cause overexpression of that gene but such multiplying may also cause genetic instability and problems when copies are integrated into the chromosomes. Gene expression is normally regulated by special “promoter” enzymes. When the promoter is present the gene will be transcribed and proteins based on the gene sequence will be created by the ribosomes in outside the nucleus of the cell. So another way to get overexpression of a gene is to increase the quantity of the promoters. Promoter clusters with up to five copies of the promoter can be created which cause significant overexpression of the targeted gene.

It may be possible in the future to create enhanced promoter clusters for the RAD52 gene which in turn would increase the production of the RAD52 protein. The increased RAD52 protein would, in turn, increase the repair activity for double stranded DNA caused by exposure to gamma radiation. This treatment could be developed as an injectable drug that would temporarily increase RAD52 production to treat a single exposure incident. It may also be possible to use gene therapy to permanently increase production of RAD52 to confer ongoing protection against radiation. This might be useful in astronauts to protect them from radiation in space.

RAD52 protein: