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04 Nov 2025
A depiction of a nuclear power plant and its cooling towers.
Nuclear Energy, Radiation Safety Versant Physics 0 comment

 The Resurgence of Nuclear Energy

The world is in a new age of change and challenge with developments in technology, climate change, and available resources. Demands for further consideration on renewable energy options are rising, and with it comes a returning interest in nuclear energy. We can see the resurgence of nuclear energy in Versant Physics’ own home state: the Palisades Nuclear Power Plant, which stopped commercial operation in 2022, is being restored through a collaborative effort of Siemens Energy and Holtec International.1

These two companies aim to enhance safety, reliability, and efficiency through their efforts to modernize and renew the Palisades to generate more than 800 megawatts (MW) of electricity.2 The goal for this energy is to power around 800,000 households. Other major companies are pursuing similar restoration projects across the United States for different reasons. Let’s explore the history of nuclear energy, its fall out of favor, and why we’re seeing attention returning to the power source.

The Rise in Nuclear Reactor Development

The first technologies for nuclear reactors and creating nuclear energy came about in the 1930s and 1940s. Its potential as a clean energy source, however, was overshadowed by government demand for nuclear bomb research for World War II. It was not until the war came to an end that a renewed focus on nuclear energy could occur. The sheer capacity of nuclear power had been demonstrated in some of the most devastating ways, but a determination to harness it for good by way of creating steam and electricity rose in the 1950s.3

The first nuclear reactor to ever produce electricity was a small reactor created in the United States by Argonne National Laboratory in 1951. Seeing the rise in potential for power generation, President Eisenhower proposed an “Atoms for Peace” program in 1953. This reoriented research effort contributed significantly towards electricity generation and inspired civil nuclear energy development in the USA.  Great progress within the United States and the rest of the world continued throughout the 1950s with the creation of new reactor designs. These included fast breeder reactors (FBRs), which produce more fissile materials than they consume and are designed to extend nuclear fuel supply to generate electricity, as well as pressurized water reactors (PWRs), a reactor originally designed for the U.S. Navy that uses pressurized water as a coolant and neutron moderator.4,5

Commercial nuclear energy reactors started appearing in 1959 in France, quickly followed by the U.S., the United Kingdom, and Russia across the 1960s.  Many of these reactors were light water designs (either PWRs or boiling water reactors, BWRs) and some could generate up to 250 MW of energy. Within the early 1970s, the world saw its first high-power channel reactors that could generate 1,000 MW of energy.3 Despite these rapid developments of increasing energy outputs, the demand for this new source of power was short lived.

Why the Quick Decline to Nuclear Energy Interest?

Just as nuclear energy orders started coming in during the 1960s, the United States and other countries creating nuclear power plants began to see a decline just as quickly in the 1970s and through the rest of the 20th century.  This was due to unresolved concerns about the latest world war and unforeseen incidents in the future.

The Anti-Nuclear Movement and the Energy Crisis of the 1970s

 Within the midst of the Cold War where the world’s superpowers were locked in their nuclear arms race, animosity towards nuclear products spread throughout the public perspective. Local and national protests grew against the use of any nuclear weaponry or power plants due to the proven potential for destruction from World War II and the looming threat created by the Cold War.6 Producers of these plants were forced to bring production to a slowdown as previous orders from the 1960s were cancelled and interest in any new requests waned.3

In 1973 during the Yom Kippur War, the Arabian state members of the Organization of Petroleum Exporting Countries (OPEC) initiated an embargo on oil exports to the U.S. This created the oil crisis from 1973 which caused the U.S. government to scramble for alternative energy sources. This led to nuclear energy coming back on the table as an option for power, but concerns surrounding the consequences of power plants had only worsened. Within the U.S., many Americans were against storage of radioactive material and waste generated from the nuclear power plants. Protests cited potential danger to the health of residents living near the sites and the negative environmental impact if any waste leaked out of containment.6

The Chernobyl, Three Miles Island, and The Fukushima Disaster Incidents

After the rise of the Anti-Nuclear Movement, incidents relating to established nuclear power plants began to occur. The first recorded nuclear power plant incident happened in 1979 at the Three Mile Island nuclear power plant in the USA. Due to a cooling malfunction, part of the core in Unit 2 of the plant melted, destroying the reactor. Although there were no injuries or adverse health effects from the event, the event caused widespread confusion and concern about the impact of the incident.7

The Chernobyl disaster occurred in 1986 and is notably the worst incident to have occurred in history. This nuclear power plant is in Chernobyl, Ukraine, and a sudden surge of power during a reactor systems test destroyed Unit 4 of the station. Investigation of the incident determined that a lack of proper safety culture caused the devastation at the Chernobyl power plant8. Many site workers were killed or had acute radiation sickness.9

Image depicting a full view of the Chernobyl nuclear power plant.

These incidents only heightened anti-nuclear movements in the end of the 20th century. Due to the strong reluctance towards increasing nuclear energy production, new facilities were rare into the early 2000s.  The Fukushima Daiichi accident of 2011, in which an unprecedented natural disaster hit Japan and overpowered the outdated tsunami countermeasures of the Daiichi site, continued to incite trepidation towards the safety of nuclear power plants.10 The world is seeing more alternative energy sources in response to climate change, but through solar, wind, and geothermal routes. Nuclear energy produces only 9% of the world’s electricity as of 2025,11 but things may change soon. After over a decade without serious troubles, eyes are returning to nuclear energy as power for new technologies.

Nuclear Energy’s New Appeal

One of the biggest technological advancements that the world is adapting to is the rise in artificial intelligence (AI). Companies across the globe are implementing their own AI systems that require very large, energy demanding data centers to function. For one request to ChatGPT, the International Energy Agency (IEA) has determined that the response the AI provides requires ten times more electricity than someone completing a Google search.12 Current power grids are struggling to keep up with the demands of artificial intelligence. In response, companies creating AI who need to maintain these data centers are casting attention towards untapped nuclear energy sources.

Who are some of the big names looking to harness nuclear energy?

One of the first deals made that suggested a reemergence of nuclear energy was in September of 2024. The tech giant Microsoft signed an agreement with Constellation Energy to restart the Unit 1 nuclear reactor at the Three Mile Island plant in Pennsylvania.13 Once the site is up and running, Microsoft hopes to have 835 megawatts (MW) of new power they can dedicate to their data centers. Whether this $1.6 billion deal is worth its steep price tag depends on time—the Three Mile Island plant originally closed in 2019 due to economic challenges. Now, Microsoft faces getting the nuclear reactors back into working order, renewing its operating licenses, and starting operations again by 2028.13

The social media and technology giant, Meta, aims to take a similar approach to Microsoft for their AI power needs. By partnering with Constellation Energy, Meta hopes to access 1,121 MW of nuclear energy through an established Illinois nuclear facility. This will bolster the electricity needs for Meta to continue its AI developments. They hope to increase data centers and important hubs for tasks like “AI model training, content delivery, and cloud services”.14

While Microsoft and Meta will be taking advantage of established nuclear power plants, Google and Amazon are approaching their move into nuclear energy differently. These companies are looking to invest in the creation of small modular reactors (SMRs). This type of plant currently doesn’t operate anywhere in the United States and only a few exist in the world. SMRs produce less than 300 MW per reactor. Amazon has made a deal with X-Energy, a company capable of designing “high-temperature gas reactors,” and Energy Northwest. They aim to create four reactor modules that would provide at least 320 MW combined.14 Meanwhile, Google has moved into an agreement with Kairos, a company that develops “molten salt-cooled, TRISO fuel-powered” reactors. The goal of power production from these future SMRs for Google would be 500 MW by 2035.14

Will nuclear energy be the long-term solution for AI needs?

The unexpected energy demand for artificial intelligence is driving these trillion-dollar companies to invest in nuclear energy potential, but will this be a long-term investment? Some suggest that the eventual solution to this power-hungry technology will be the technology itself. Artificial intelligence is continuously growing, being trained to learn more and do more. Some believe that AI algorithms will eventually become the best path to determining its own energy management. This would be achievable through its capacity to “identify patterns in data, detect anomalies, and anticipate and forecast future results”.12

Given enough time to “self-reflect”, AI could determine how to optimize its own functioning to reduce its carbon footprint and power necessary to be sustained. In the meantime, nuclear power plants will be giving these tech giants an opportunity to obtain the energy they need. With the increasing pressure of honoring climate commitments and lowering greenhouse gases, they may also find that nuclear energy suits more than just their AI needs.

Conclusion

Nuclear energy is still an industry that is seen first for the disastrous events from the past and their repercussions. Power plants are considered as hazardous potential for nuclear waste leaks, core meltdowns, and a threat for radiation exposure to those who live nearby. However, as the need for cleaner energy increases in demand, we may find that nuclear is an option to reconsider.

Handling of radiation and nuclear power has improved over recent decades. Now more than ever, safety concerns are taken seriously to avoid repetitions of historical incidents. With investments from large companies like Microsoft and Meta, the resurgence of nuclear energy could provide a path to expanded opportunities of clean power provision for more than just AI data centers. By focusing on safety, responsible handling, and sustainability as core features of future nuclear power plants, perhaps the true potential for nuclear energy will be revealed.

Sources

  1. Palisades Nuclear Power Plant. Siemens-energy.com. Published 2025. Accessed October 30, 2025. https://www.siemens-energy.com/global/en/home/references/recommissioning-palisades-nuclear.html
  2. Davidson K. Palisades Nuclear Plant on Lake Michigan shoreline one step closer to reopening • Michigan Advance. Michigan Advance. Published July 25, 2025. Accessed October 30, 2025. https://michiganadvance.com/briefs/palisades-nuclear-plant-on-lake-michigan-shoreline-one-step-closer-to-reopening/
  3. ‌World Nuclear Association. Outline History of Nuclear Energy. world-nuclear.org. Published May 2, 2024. https://world-nuclear.org/information-library/current-and-future-generation/outline-history-of-nuclear-energy
  4. Breeder reactor – Energy Education. Energyeducation.ca. Published 2017. https://energyeducation.ca/encyclopedia/Breeder_reactor
  5. World Nuclear Association. Nuclear Power Reactors. world-nuclear.org. Published January 23, 2025. https://world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-power-reactors/nuclear-power-reactors
  6. Antinuclear movement of the 1970s | EBSCO. EBSCO Information Services, Inc. | www.ebsco.com. Published 2022. https://www.ebsco.com/research-starters/history/antinuclear-movement-1970s
  7. World Nuclear Association. Three Mile Island Accident – World Nuclear Association. world nuclear association. Published October 11, 2022. https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/three-mile-island-accident
  8. World Nuclear Association. Sequence of Events – Chernobyl Accident Appendix 1 – World Nuclear Association. World-nuclear.org. Published 2022. https://world-nuclear.org/information-library/appendices/chernobyl-accident-appendix-1-sequence-of-events
  9. Backgrounder on Chernobyl Nuclear Power Plant Accident. NRC Web. Published 2015. https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/chernobyl-bg
  10. World Nuclear Association. Fukushima Daiichi Accident. world-nuclear.org. Published April 29, 2024. https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/fukushima-daiichi-accident
  11. Nuclear Power Reactors – World Nuclear Association. world-nuclear.org. https://world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-power-reactors/nuclear-power-reactors#how-does-a-nuclear-reactor-work
  12. United Nations. Artificial intelligence: How much energy does AI use? United Nations Western Europe. Published April 7, 2025. https://unric.org/en/artificial-intelligence-how-much-energy-does-ai-use/
  13. Moseman A. How to Restart a Nuclear Reactor. IEEE Spectrum. Published October 2, 2024. https://spectrum.ieee.org/three-mile-island
  14. Wolinski SJ. AI’s Energy Demands and Nuclear’s Uncertain Future | GJIA. Georgetown Journal of International Affairs. Published April 16, 2025. https://gjia.georgetown.edu/2025/04/16/ais-energy-demands-and-nuclears-uncertain-future/

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30 Jul 2025
Ionizing Radiation, Irradiation, Radiation Safety, Uncategorized Versant Physics 0 comment

The Banana Equivalent Dose: Demystifying Radiation

The idea that radiation exposure is inescapable through everyday life might cause a feeling of concern or even trepidation. To make it more palatable to the public, a somewhat quirky unit of measurement was born for absorbed radiation dose. This is the “Banana Equivalent Dose”, or BED (not to be confused with the other well-known BED, the Biologically Effective Dose). Bananas, a fruit found in many homes, all contain a very small but measurable dose of ionizing radiation. The BED provides an opportunity to bring an unusual yet helpful perspective towards discussions on radiation exposure so that the science behind radiation feels more accessible and less mysterious. Let’s explore the BED, why radiation in food exists, and what it teaches us about daily radiation encounters.

What is the Banana Equivalent Dose?

The Banana Equivalent Dose (BED) is an informal unit of measurement that expresses a radiation dose in terms of the amount one person would receive from eating a single banana.1 Instead of the knowledge that radiation can exist in our food being a cause for concern, it provides a chance for better understanding of a difficult topic. The idea of the BED offers a way for the public to frame seemingly large or unfamiliar numbers relating to ionizing radiation into a more meaningful context. Although it isn’t an official unit endorsed by regulatory agencies or scientific organizations, the BED has shown to be an easier baseline for regular citizens to comprehend than attempting to explain rems or sieverts.

The average BED is about 0.1 microsieverts (μSv) per banana (1 μSv = 0.000001 sieverts, a recognized unit for measuring ionizing radiation dose).1 For some context, an average person will receive roughly 2,000 to 3,000 μSv per year due to natural background radiation like cosmic rays, radon gas, and terrestrial sources. This is equivalent to 20,000 to 30,000 bananas. When someone consumes a single banana, a minuscule addition to this background radiation occurs.

Why Are Bananas Radioactive?

Bananas are well-known for being rich in potassium, which is an essential mineral for human nutrition. They gain most of this potassium through the uptake of the mineral via the roots of their trees. There is also deposition, which is when the fruit absorbs radioactive particles in the air that settle on it.2 Naturally occurring potassium will normally be comprised of the mostly stable isotope potassium-30, but close to 0.012% of the potassium is the radioactive isotope, potassium-40. Potassium-40 decays with a half-life that equals about 1.3 billion years which means it releases radiation at a very slow rate.3

After eating a banana, both radioactive and non-radioactive potassium isotopes enter your body, becoming part of the natural chemical makeup. The human body strictly regulates potassium levels, so any excess is excreted fairly quickly. After some time to digest and excrete, your body is able to return your internal dose of potassium-40—including its radiation—to its equilibrium, regardless of whether you might eat one banana or even a dozen.3

How the Banana Equivalent Dose Came to Be

The true origin of the Banana Equivalent Dose is not clearly recorded in any sources. However, it is reasonable to surmise that the unit was suggested during research on radiation found in foods. The earliest known mention of the BED is from 1995 on a recorded email chain from Gary Mansfield. An employee at Lawrence Livermore National Laboratory at the time, Gary suggests that he found the BED to be “very useful in attempting to explain infinitesimal doses (and corresponding infinitesimal risks) to members of the public”.4

By comparing common procedures like a typical chest X-Ray (about 1000 BEDs) or actions like flying from New York to London (about 400 BEDs) to the dose from a banana, experts can create an easier connection of these common, low-level exposures to the overall idea of radiation safety. Even large organizations like the United States Environmental Protection Agency (EPA) reference the BED in public educational articles.2

The BED has remained a popular option for comparison in scientific forums and educational websites due to familiarity and relatability. Radiation is given a more understandable setting within bananas. The common household snack serves as a reminder that sometimes exposure is not as disastrous as previously believed.

Understanding Radiation Dose with the BED

An issue with radiation being an enigma for many is the misconception that all radiation is harmful, regardless of dose. There are many circumstances where that is not the case. The BED assists with putting radiation exposure into a new light:

  • Dental X-ray: Roughly equivalent to 50 BEDs
  • Yearly dose from living near a nuclear power plant: 1 – 100 BEDs
  • Chest CT scan: 70,000 BEDs
  • Typical targeted dose used in radiotherapy (one session): 20,000,000 BEDs1

Although it may be hard to fully imagine a stack of twenty million bananas, it proves to be a more tangible idea to promote informed understanding of the amount of radiation exposure in a procedure than the more abstract measurements of sievert values for the public.

What Other Foods with Radiation Exist?

Many foods naturally absorb radioisotopes from the soil and water in which they grow, putting bananas into some popular company for regular consumption. Here are some of the most recognizable foods with radioactive elements:

  • Brazil nuts are well-known for having high levels of radium-226 and radium-228, with doses that can, at times, be even higher than bananas. This is because Brazil nut trees have deep roots that access radium-rich soil and lead to these concentrations.
  • Potatoes are another potassium-rich food and contain potassium-40. Unlike bananas, however, they also absorb small amounts of uranium and thorium.
  • Carrots and red meat can accumulate some minor amounts of radioisotopes, particularly potassium-40. However, their doses are minimal compared to annual background radiation.
  • Some beer has trace amounts of potassium-40—not unlike other plant-derived foods.5

Of course, it is important to note that, despite the radioactivity in these foods, they pose no health risks when considering consumption in a normal diet. As previously mentioned, the human body is capable of handling low doses of naturally occurring radiation. Regulatory agencies also take care to monitor food safety to safeguard public health.  

Conclusion: The Public Value of the BED

When it comes to encouraging better understanding of a complex subject like radiation exposure, there’s value in linking it to a familiar concept in a person’s life. Not only does the BED provide a light-hearted opportunity to understand your day-to-day exposure but it also helps show that consuming food with absorbed radioactive elements does not normally pose a risk to one’s health or make a person radioactive—far from it, even. The Banana Dose Equivalent gives the public a dose measurement that “peels” back the layers of uncertainty to see that radiation is a natural part of the world that’s findable in the food we eat and even ourselves.

Sources

  1. P2 Nuclear and Par-Cle Physics –Dan Protopopescu. https://www.ppe.gla.ac.uk/~protopop/teaching/NPP/P2-NPP.pdf
  2. ‌Natural Radioactivity in Food. US EPA. Published November 27, 2018. https://www.epa.gov/radtown/natural-radioactivity-food
  3. ‌Schwarcz J. McGill University. Office for Science and Society. Published December 30, 2018. https://www.mcgill.ca/oss/article/you-asked/it-true-banana-radioactive
  4. Banana Equivalent Dose. Iit.edu. Published 2025. http://health.phys.iit.edu/extended_archive/9503/msg00074.html
  5. Helmenstine A. These 10 Common Foods Are Radioactive. ThoughtCo. Published 2014. https://www.thoughtco.com/common-naturally-radioactive-foods-607456
31 Jan 2025
Background Radiation, Cancer Treatment, Irradiation, Radiation Therapy Versant Physics 0 comment

What Really Happens? The Impact of Radiation Inside the Body

What is Radiation?

Radiation is a fundamental phenomenon that exists as a natural part of the world and universe. It is the emission and propagation of energy in the form of waves or particles through space or a material medium. At its most basic level, radiation occurs when unstable atomic nuclei release energy by emitting particles (such as alpha particles, beta particles, or neutrons) and/or electromagnetic waves (such as gamma rays). Electromagnetic radiation is also produced through several other processes: X-rays are generated when electrons transition between inner atomic energy levels or when fast-moving electrons are decelerated (bremsstrahlung), while UV radiation primarily comes from electron transitions in excited gases and thermal emission from very hot objects such as the sun. The impact of radiation has the potential to be either beneficial or destructive to biological systems.

Ionizing and Non-ionizing Radiation

Radiation is categorizable into two groups: ionizing radiation and non-ionizing radiation. Ionizing radiation has enough energy to remove tightly bound electrons from atoms, creating charged particles (ions). This group includes alpha particles, beta particles, gamma rays, X-rays, and neutrons. Ionizing radiation is commonly associated with medical applications, such as X-rays and radiotherapy, but it also occurs naturally, as in the form of cosmic rays or radon decay.

In contrast, non-ionizing radiation does not have sufficient energy to ionize atoms or molecules. This group includes ultraviolet (UV) radiation, visible light, infrared radiation, microwaves, and radio waves. However, ultraviolet (UV) radiation exists on the boundary: lower-energy UV radiation is typically non-ionizing, while higher-energy UV radiation, such as extreme UV, can ionize atoms and molecules. Non-ionizing radiation is generally less harmful and technologies such as communication devices and heating systems use it. On the beneficial side, the visible light radiation coming from the sun enables photosynthesis in plants and infrared radiation provides warmth. As is also common knowledge, the use of X-Rays in medicine is very popular in current times.

Regardless of whether radiation is produced naturally through something such as UV rays, or the high-energy radiation created by humans for radiotherapy and other medical procedures, there are biological impacts for any living creature that encounters it. Today, we will explore the impact of radiation on a cellular level and why, despite these potentially harmful effects, the risk is worth the reward when it comes to continued radiation use.

How Does it Affect the Body Overall?

Ionizing radiation can cause damage to one’s cells in different ways:

Cellular Impact of Radiation

Although any cell within the body exposed to ionizing radiation can have a reaction to it, the impact of this radiation depends heavily on which types of cells are exposed and the intensity of the radiation. Cells, by default, have mechanisms to repair DNA damage. Should the repair be successful, then the cell can continue to function as normal.

Some of the human body’s cells, especially those that have rapidly dividing tissues such as bone marrow and the gastrointestinal system, are more vulnerable to radiation damage.3

Animal Cells and Irradiation Effects

  1. DNA Damage and Mutations: Damage to DNA is probably the most significant consequence of radiation exposure. Radiation can cause single-strand or double-strand breaks in the DNA, which may lead to mutations or chromosomal abnormalities as a result of errors in the repair process. Any such DNA mutation can alter how genes normally function and may result in cancerous growths or even developmental abnormalities, should the cell replicate with damaged DNA.4
  2. Cell Death: Most commonly, cell death from radiation is mitotic death. During the process of cell division, damage to the chromosomes cause cells to fail to complete their replication and die. This occurs most often when radiation damage is severe enough, as happens with double strand breaks, causing failed or incorrect repair. A secondary type of cell death that may occur is apoptosis. Apoptosis, known as programmed cell death, is normally a natural process to aid in getting rid of dysfunctional or no longer needed cells. For example, apoptosis is what allows the tadpole to lose its tail. Radiation damage may also cause a cell to enter into the apoptosis cycle leading to cell death and impaired organ function.5 Radiation induced apoptosis, however, is highly dependent on the type of cell being most common blood cells and cells associated with the immune system.
  3. Genetic Instability and Cancer: One of the most concerning effects of radiation on cells is the potential to cause cancer. The DNA mutations mentioned earlier can lead to the development of oncogenes (genes that promote cancer) or the inactivation of tumor suppressor genes. When these changes happen in critical genes that control the cell cycle and cell division, it can result in uncontrolled cell growth. This, more often than not, leads to cancer.5

Plant cells also may suffer radiation damage. Due to differences of structure and metabolism between animal and plant cell types, plant cells have a higher resistance to the effects of radiation making them more tolerant to ionizing radiation than animals.6 For plants, radiation has a less significant impact and can sometimes produce beneficial effects.

Plant Cells and Irradiation Effects

  1. DNA Damage and Mutations: As with animal cells, the nucleus of plant cells is the area of highest injury from ionizing radiation. The amount of damage that may occur to the DNA is dependent on chromosome volume. This volume changes between plants and is also affected by the different stages of the plant life cycle. Mutations (DNA deletions, base substitutions, and chromosomal alterations) can vary from non-lethal to lethal depending on the dosage of radiation exposure. 6
  2. Phenotypical Responses: As a consequence of the genetic mutations plant cells may develop after radiation exposure, the plant itself can go through a phenotypical response such as reduced growth, altered leaf morphology, and impaired development. High doses of irradiation (several Gy) can likely cause structural modifications during the plant’s growth, but chronic low levels of radiation may also introduce changes in plant traits. These studies are normally done with plant seeds that are irradiated and then observed as they develop. However, if the exposed cells have greater radioresistance, this resistance will prevent them from producing a more pronounced phenotypical response as the seed matures.6
  3. Photosynthesis: High doses of gamma radiation exposure to plants can result in a decrease of photosynthesis by disrupting the photosynthetic pigment–chlorophyll–and the photosynthetic electron transfer rate in some plants. As with the potential for DNA damage or mutations however, the impact to photosynthesis can be influenced by the plant’s developmental stage with younger or actively growing plants potentially experiencing a more significant impact compared to mature plants.6

How Radiation can Beneficially Impact the Body

Despite the tendency to associate the aforementioned biological effects with harm, radiation can have positive applications. These are mostly within the medical field but are recognizable throughout other industries as well. Here are a few ways that humans have turned the potency of radiation into a benefit:

Cancer Treatment (Radiotherapy):

Cancer treatment is, unsurprisingly, one of the most significant uses of radiation for good. High-energy radiation is usable for targeting and destroying cancerous cells by decreasing the rate of tumor cell proliferation through cell cycle arrest stimulated by DNA damage. By preferentially focusing radiation on solid tumors and limiting the dose to normal critical structure, cancer cells may be either killed or shrunk sufficiently to prevent cancer from spreading or to make it easier to remove through other means. Cancer cells divide rapidly, which makes them more sensitive to radiation than normal cells making them an ideal target for radiation therapy.7

  • Radiation in Chemotherapy: Radiation therapy is usable in conjunction with chemotherapy drugs, which increases the effectiveness of an overall treatment plan and can prevent tumor growth.8
  • Precision Medicine: This method was designed to help healthcare providers deliver more personalized treatments. In cancer care, it considers how variations in specific genes or proteins in a patient’s cancer cells may influence treatment choices. Radiation can benefit cancer treatment specifically through precision medicine when using targeted therapy that includes radiopharmaceuticals.9 An example of a targeted therapy is one that uses antibodies to which a radioactive atom has been attached. The antibody recognizes particular antigens expressed by tumor cells and bind to the cell thereby delivering its radioactive package.

Medical Imaging and Diagnostics

Diagnostic work and medical imaging benefit from radiation as well, as we’ve covered in previous blogs. Whether they are imaging options such as X-rays and CT scans, or nuclear medicine diagnostics using injected radioactive tracers, these techniques allow doctors to visualize internal structures of the body. This helps with diagnosis and monitoring of various health conditions and provides detailed anatomical information needed for planning radiation therapy. Although these procedures do involve exposure to low doses of radiation, the reward of accurate diagnosis and treatment planning to manage radiation treatment in the long run is worth the small but inherent risk.

Sterilization and Disinfection

Somewhat within and outside of the medical field, sterilizing medical equipment and food products is possible with ionizing radiation. This helps to reduce the risk of foodborne illnesses and infections. This is a process known as radiation sterilization. Through it, controlled doses of radiation can help to destroy bacteria, viruses, and other pathogens.

Balancing the Positive and Negative Aspects

The impact that radiation has at the cellular level and on the overall body is a double-edged sword: the potential to heal can also be potential for harm. When using radiation for things like treatment or imaging, the difficulty lies in ensuring as small a risk as possible while maximizing the benefit. Precise and controlled radiation doses in these procedures require careful planning and monitoring that have been developed over the years.

One of the arguments for the benefits of radiation exists in a hypothesis for how radiation can impact the body depending on dosage. Despite the harmful effects of radiation that we detailed earlier, scientists have seen evidence for some beneficial effects in an area known as radiation hormesis.

The radiation hormesis model supports the idea that low-dose radiation can stimulate adaptive or protective mechanisms within cells (both plant and mammalian) when exposed. This low-dose radiation can aid with prevention of both spontaneous and toxicant-related cancers, along with other adverse health effects. Through this stimulation, the adaptive protection developed by the cells would thereby improve health.10 The radiation hormesis model, though well known by professionals in the field, requires more research, time, and development. There are no accredited organizations in the medical physics world that recognize radiation hormesis as a usable model and the LNT (Linear-No-Threshold) model maintains as the worldwide safety standard.

Conclusion

Even if human-made radiation had never come to exist, natural radiation makes it an intrinsic part of our lives. Knowing the biological impact that radiation can have down to the cellular level allows us to harness its potential in the safest ways possible for the greatest benefits and smallest risk. Although radiation can damage cells in a way that leads to mutations, cancer, or even organ failure, it is vital in treating diseases, making diagnoses, and sterilizing necessary items like food or medical equipment. As with many sources in the world, humans must strike a balance with its use. Through understanding the full effects of radiation, good and bad, we pave the way to using radiation in an effective and responsible manner.

Sources

  1. Ionizing Radiation and Non-Ionizing Radiation – Frequently Asked Questions a RESOURCE for VETERANS, SERVICE MEMBERS, and THEIR FAMILIES. https://www.warrelatedillness.va.gov/WARRELATEDILLNESS/education/factsheets/Radiation.pdf
  2. Di Meo S, Venditti P. Evolution of the Knowledge of Free Radicals and Other Oxidants. Oxidative Medicine and Cellular Longevity. 2020;2020:1-32. doi:https://doi.org/10.1155/2020/9829176
  3. Nuclear Regulatory Commission. Reactor Concepts Manual Biological Effects of Radiation Biological Effects of Radiation.; 2023. https://www.nrc.gov/reading-rm/basic-ref/students/for-educators/09.pdf
  4. Baskar R, Dai J, Wenlong N, Yeo R, Yeoh KW. Biological response of cancer cells to radiation treatment. Frontiers in Molecular Biosciences. 2014;1(24). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4429645/
  5. Little JB. Principal Cellular and Tissue Effects of Radiation. Nih.gov. Published 2014. https://www.ncbi.nlm.nih.gov/books/NBK12344/
  6. Arena C, De Micco V, Macaeva E, Quintens R. Space radiation effects on plant and mammalian cells. Acta Astronautica. 2014;104(1):419-431. doi:https://doi.org/10.1016/j.actaastro.2014.05.005
  7. ‌ American Cancer Society. How Radiation Therapy Is Used to Treat Cancer. www.cancer.org. Published December 27, 2019. https://www.cancer.org/cancer/managing-cancer/treatment-types/radiation/basics.html
  8. Rallis KS, Yau THL, Sideris M. Chemoradiotherapy in Cancer Treatment: Rationale and Clinical Applications. Anticancer Research. 2021;41(1):1-7. doi:https://doi.org/10.21873/anticanres.14746
  9. Xiong Y, Jian H, Han X, Li L, Zhou L. A decade of incremental advances in radiopharmaceuticals: a promising future ahead. Journal of Translational Medicine. 2024;22(1). doi:https://doi.org/10.1186/s12967-024-05891-4
  10. Vaiserman AM. Radiation hormesis: historical perspective and implications for low-dose cancer risk assessment. Dose Response. 2010;8(2):172-191. Published 2010 Jan 18. doi:10.2203/dose-response.09-037.Vaiserman

23 Sep 2024
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Health Physics, Nuclear Medicine, Radiation Safety Versant Physics 0 comment

Dr. Thomas Morgan: An Inspirational Impact on Health Physics

Dr. Thomas Morgan, a Senior Health Physicist with Versant Physics, was recently made a Fellow by the Health Physics Society. As a long-standing scientist within the world of radiation science and health physics, this is an achievement he more than deserves. A 1983 graduate of the University of California, Irvine, Dr. Morgan has built a distinguished career spanning several decades. His academic and professional achievements reflect a deep commitment to advancing the field and training future generations of scientists.

Academic Foundations and Early Training

Dr. Morgan’s academic path laid a strong foundation for his future contributions to radiation science. At UC Irvine, he earned bachelor’s degrees in both biology and chemistry. These disciplines provided him with a robust understanding of the scientific principles underlying medical physics and radiological sciences. Dr. Morgan’s educational journey didn’t stop there. He continued at UC Irvine to obtain both a master’s degree and a Ph.D. in radiological sciences, specializing in medical physics.

During his time as a graduate student, Dr. Morgan underwent rigorous training in operating nuclear reactors. He became licensed by the Nuclear Regulatory Commission as a Senior Operator of the TRIGA Mk 1 nuclear reactor on campus. This hands-on experience with nuclear technology and safety would become a cornerstone of his career.

Contributions to Research and Publications

Dr. Morgan’s research contributions are significant and varied. His work spans several critical areas, including radiation biology and physics, cancer biology, clinical cancer research, and radiation safety. Over the years, he has directed and conducted valuable research. This work has advanced our understanding of how radiation affects biological systems. The research also produced options for how it can be used safely and effectively in medical treatments.

The scholarly output of Dr. Thomas Morgan is impressive, with more than 35 peer-reviewed publications to his name. Additionally, he has co-authored three books and six book chapters. This further solidifies his reputation as a leading expert in his field. In the Versant Physics newsroom, we covered the publication of one of his more recent publications with HPS. Publications like these not only reflect his deep knowledge but his dedication to sharing that knowledge with the broader scientific community.

Commitment to Education and Training

Dr. Morgan’s commitment to education is evident from his extensive teaching experience. He was hired by the Southern California Permanente Medical Group in Los Angeles, California, to teach radiation biology resident physicians in the Radiation Therapy Department. He was appointed as an Adjunct Professor of Health Sciences at California State University of Long Beach. This was where he taught radiation biology to radiation therapy radiologic technologists. Dr. Morgan took every role in educating these future professionals with determination to better the future. This underscores his belief in the importance of training and mentoring the next generation of radiation practitioners.

Dr. Thomas Morgan also taught health physics to medical physics graduate students at Columbia University in New York City. There he served as an Adjunct Professor of Applied Physics and Mathematics. Through these roles, Dr. Morgan has not only imparted his knowledge but has also helped shape the careers of the next generation of medical physicists.

Professional Roles Through a Dedicated Career

Dr. Morgan’s professional career includes several prestigious positions in radiation safety and environmental health. He served as the Radiation Safety Officer (RSO) at the Southern California Permanente Medical Group’s Los Angeles campus. Dr. Morgan was also the RSO at the University of Rochester and Strong Memorial Hospital in Rochester, New York. His expertise in managing radiation safety protocols in these settings was crucial for maintaining safe and compliant operations.

Before his retirement in 2018, Dr. Morgan held a prominent role as the Executive Director of Environmental Health and Safety and Chief Radiation Safety Officer at Columbia University and the Columbia University Irving Medical Center. In this capacity, he was responsible for overseeing all aspects of environmental health and safety. This included radiation safety, ensuring that the institution adhered to the highest standards.

Leadership in Professional Organizations

Dr. Morgan’s contributions extend beyond his research and teaching. He has always been an active member of the Health Physics Society. Dr. Morgan even served as past president of the Western New York and Florida chapters. His leadership roles also include chairing several committees and serving as a Director of the Society. In recognition of his service and contributions to the field, he was named a Fellow of the Health Physics Society in 2023.

His editorial roles further illustrate his commitment to advancing the field. Dr. Morgan is currently an Associate Editor of the Health Physics Journal. He also previously served as an Associate Editor of Applied Physics Research. These positions highlight his ongoing engagement with the latest research and developments in health physics.

Certification and Licensure

Dr. Morgan’s professional qualifications are extensive. He is certified by the American Board of Health Physics in the practice of comprehensive health physics and is licensed to practice medical health physics in New York, Florida, and Texas. These credentials underscore his expertise and commitment to maintaining the highest standards in his practice.

Personal Life and Volunteer Work

Outside of his professional life, Dr. Morgan enjoys residing in Sarasota, Florida, with his wife, Diane. He remains actively involved in his community through volunteer work. He serves as a docent at the Mote Marine Laboratory, where he helps educate the public about marine science. Additionally, his involvement with the Manasota Medical Reserve Corps reflects his dedication to supporting public health and safety.

A Continuing Devotion to Radiation Science and Health Physics

Headshot of Dr. Tom Morgan.

The career of Dr. Thomas Morgan is a testament to his passion for radiation science and health physics. From his early academic achievements to his significant research contributions, teaching roles, and leadership positions, his impact on the field is profound. His dedication to education, professional service, and community involvement underscores a lifetime of commitment to advancing science and improving safety. As a newly named Fellow of the Health Physics Society, Dr. Morgan’s legacy continues to inspire and shape the future of radiation science.

29 Aug 2024
Cancer Treatment, Nuclear Medicine Versant Physics 0 comment

Celebrating the Achievements of Dr. Darrell R. Fisher:  A Journey of Scientific Excellence

Earlier this year, the Columbia Chapter of Health Physics Society and the Georgian Health Physics Association nominated Dr. Darrell R. Fisher for the 2024 Distinguished Scientific Achievement Award of the Health Physics Society (HPS). Fisher is a nuclear medicine physicist with Versant Medical Physics and Radiation Safety. He received the Distinguished Scientific Achievement Award in July 2024, during the 16th International Congress of the International Radiation Protection Association and 69th HPS Annual Meeting in Orlando, Florida. The award recognized Dr. Fisher’s scientific contributions over a career spanning more than five decades in applied radiation safety sciences, including internal dosimetry, radiobiology, radiochemistry, and design and testing of radiopharmaceuticals and medical devices. His innovative research has led to numerous significant advancements in the applied radiation health sciences. 

Discoveries in Chelation Therapy and Radiotoxicity

One of Dr. Fisher’s early discoveries was identifying the toxicity and congenital birth defect teratogenicity of the heavy-metal chelating agent CaNa3DTPA compared to the non-toxic ZnNa3DTPA. This research showed the importance of maintaining cellular zinc and manganese availability during critical growth periods to ensure uninterrupted cell division.  His work was instrumental in enhancing the safety and effectiveness of emergency decorporation therapy for nuclear workers accidentally exposed to plutonium, neptunium, and americium. By establishing the safety of ZnNa3DTPA, Dr. Fisher’s work paved the way for safe and effective treatments after actinide contamination events, significantly impacting emergency response protocols and worker safety in nuclear industry.

Advances in Applied Microdosimetry

Dr. Fisher performed the first microdosimetry calculations for plutonium-238 and plutonium-239 in beagle dog lung tissue specimens. His research disproved the “hot particle hypothesis” claimed by Thomas Cochran and Arthur Tamplin; Fisher showed that their hypothesis could not be supported by dosimetry or radiobiology.  Fisher described the fundamental science underlying relative biological effectiveness (RBE) relationships between alpha-particle dose and two critical biological endpoints: cellular mutation and primary DNA damage. This work demonstrated that varying the specific activity and spatial geometry of plutonium microsphere sources could result in vastly different biological outcomes at constant absorbed dose. These findings were pivotal to better understanding radiation effects at the microscopic level, influencing safety standards, and advancing what would later become new cancer treatment approaches with alpha-emitting radionuclides.

Innovations in Cancer Treatment

Dr. Fisher was an early proponent of short-lived alpha emitters such as radium-223 and actinium-225 for cancer treatment. He performed the first cellular-level microdosimetry calculations for alpha-emitter-radiolabeled monoclonal antibodies used in cell-targeted radioimmunotherapy. His pioneering work in developing treatment-planning dosimetry for clinical radioimmunotherapy supported the high-dose treatment of relapsed lymphoma, leukemia, and multiple myeloma patients.  In the laboratory, he helped to develop and test several innovative alpha-emitter complexing agents, including macrocyclic cages and nanoparticle delivery constructs for next-generation therapies.

Contributions to Uranium Toxicology

Dr. Fisher’s assessments of dosimetry and health effects from uranium intakes led to a modified biokinetic model for inhaled uranium hexafluoride compounds. His research provided crucial insights following the Sequoyah Fuels accident in Oklahoma, where workers were exposed to uranium hexafluoride. Dr. Fisher’s model improved the understanding of uranium’s behavior in the body, leading to better understanding of uranium toxicity. 

Pioneering Work in Radionuclide-Polymer Composites

Dr. Fisher conceived, designed, patented, and tested novel radionuclide-polymer composites employing insoluble crystalline yttrium-90-phosphate microspheres administered in a thermo-reversible hydrogel delivery matrix. This innovation has enabled direct interstitial therapy of nonresectable solid tumors, providing new avenues for cancer treatment in both humans and veterinary animals.  Precision radionuclide therapy by direct intra-tumoral injection maximizes therapeutic ratios, a key measure of treatment safety and efficacy.  His work has enabled highly efficient delivery of radiation to tumors, minimizing damage to surrounding healthy organs and tissues and associated side-effects of radiation therapy.

Enhancing Patient Safety in Nuclear Medicine

Dr. Fisher helped develop and published practical methods for patient-specific dosimetry to characterize the severity of inadvertent radiopharmaceutical extravasations in diagnostic and therapeutic nuclear medicine.  Fisher has specialized in medical internal radiation dosimetry, an essential element of managing patient safety and improving therapy outcomes. 

Lifelong Commitment to Radiation Safety

Darrell Fisher’s journey in health physics began in 1973 as an undergraduate research assistant at the University of Utah’s Radiobiology Laboratory. His early research on extracting americium-241 from skeletal surfaces in live mice laid the foundation for his future contributions to radiation safety and radiobiology.  Over the years, his work has led to significant advancements in understanding and mitigating the effects of radiation exposures in medical and occupational settings. His dedication to the field is evident in his continuous efforts to improve safety standards, develop innovative treatment methods, and educate future generations of health physicists.

The 2024 Distinguished Scientific Achievement Award recognizes Dr. Fisher’s commitment to scientific excellence and discovery for work that not only advances scientific knowledge but also improves patient care and radiation safety.  His diverse contributions to the field of applied radiation safety sciences, in collaboration with highly respected research associates and colleagues worldwide, have been impactful. His innovative research, spanning over 50 years, has led to significant advancements in worker safety, dosimetry and microdosimetry, radionuclide therapy treatment planning, direct interstitial treatment of inoperable tumors, and patient safety in nuclear medicine.

Dr. Fisher Headshot, 2024.
27 Mar 2024
Airplane flight crew character design. Pilot and stewardess flat vector illustration
Background Radiation, Health Effects, Ionizing Radiation, Radiation Safety Versant Physics 0 comment

Flight Crews and Radiation Exposure

Flight crews are among the occupational groups most exposed to ionizing radiation, with an average annual effective dose surpassing that of other radiation-exposed workers in the United States, excluding astronauts.1 This elevated exposure is primarily due to the high levels of cosmic radiation encountered at flight altitudes, which can pose significant health risks to pilots and cabin crew members.2 In this blog post, we’ll explore the nature of cosmic radiation, its potential health effects, current exposure levels for aircrews, as well as the guidelines and regulations in place to ensure their safety.

What Is Cosmic Ionizing Radiation?

As we’ve touched on in a previous blog, cosmic ionizing radiation–or simply cosmic radiation–originates from beyond Earth’s atmosphere. Additionally, it consists of two main components: galactic cosmic radiation (GCR) and solar particle events (SPEs).3,4

Galactic Cosmic Radiation

GCR is a constant background radiation that permeates interstellar space, originating from distant stars and galaxies. It is composed primarily of high-energy protons (85%) and alpha particles (14%). There is also a small fraction of heavier nuclei (1%) ranging from lithium to iron and beyond. These particles span a wide energy range, and as a result some reach extremely high energies capable of penetrating deep into the Earth’s atmosphere and passing through aircraft shielding.5

Solar Particle Events (Solar Flares)

Solar particle events, on the other hand, are sporadic bursts of intense radiation associated with solar flares and coronal mass ejections. During an SPE, the Sun ejects a large number of high-energy protons and other particles that can reach Earth within hours to days. While less frequent than GCR, SPEs can dramatically increase radiation exposure for flight crews, particularly those on polar routes where the Earth’s magnetic field provides less protection.6,7

At higher altitudes, such as those typically encountered during air travel, the Earth’s atmosphere provides less shielding against cosmic radiation, resulting in increased exposure for flight crews and passengers.

Several studies that have investigated the difference in cosmic ray levels at various altitudes versus ground level found that the dose rate of cosmic radiation at a cruising altitude of 30,000 feet was approximately 10 times higher than at sea level.

The specific increase in cosmic ray exposure at higher altitudes is influenced by several factors, including the solar cycle (solar maximum vs. solar minimum), geomagnetic field strength, and also the path of the flight (polar routes are exposed to higher levels of cosmic rays). For example, during periods of high solar activity (solar maximum), the increased solar wind can actually shield the Earth from some cosmic rays, slightly reducing the exposure at high altitudes. Conversely, during a solar minimum, the cosmic ray intensity can be higher.

Estimates of the number of hours that have to be flown in order to receive an effective dose of 1 mSv at 30,000 feet are 510 hours at a latitude of 30o South and 1,330 hours at the equator.8

Health Effects and Uncertainties

The health risks associated with radiation exposure are generally well-documented. Prolonged exposure to high levels of radiation can increase the risk of cancer, cataracts, as well as other adverse health effects.  However, quantifying the specific risks associated with the chronic low-dose radiation experienced by flight crews remains a challenge.

The World Health Organization’s International Agency for Research on Cancer (IARC) acknowledges that ionizing radiation causes cancer in humans and is also associated with reproductive problems. However, when it comes to cosmic ionizing radiation, several uncertainties remain:

  1. Cancer Risk: Most radiation health studies have focused on groups exposed to much higher doses from different types of radiation (such as atomic bomb survivors or patients receiving radiation therapy).9 Due to this, the specific link between cosmic ionizing radiation and cancer risk is not yet fully understood.
  2. Reproductive Health: Miscarriages and birth defects related to cosmic radiation exposure are still not definitively established.10

Despite the limitations of current research, several studies have suggested that flight crews may have a higher incidence of certain cancers compared to the general population. These include breast cancer, melanoma, as well as non-melanoma skin cancers.11,12 However, the causal link between cosmic radiation exposure and these increased risks has not been definitively established. Other factors, such as lifestyle and genetic predisposition, may also play a role.13

Exposure Levels for Flight Crews

Recent dose and risk assessments by a wide variety of investigators have demonstrated the need to dedicate further attempts to quantify potential radiation exposure.14 The National Council on Radiation Protection and Measurements (NCRP) reports an average annual effective dose of 3.07 mSv for flight crews; most of this exposure comes from natural radiation:

  • Estimates of annual aircrew cosmic radiation exposure range from 0.2 to 5 millisieverts (mSv) per year depending on factors such as flight routes, altitude, and solar activity.
  • Solar particle events occur less frequently, but during events, exposure levels can increase substantially and potentially lead to higher doses over short periods.

Guidelines and Regulations

While there are no official dose limits specifically for aircrew in the United States, national and international guidelines provide context:

  • International Commission on Radiological Protection (ICRP): Recognizes aircrew as radiation-exposed workers. They also recommend an effective dose limit of 20 mSv per year averaged over 5 years (totaling 100 mSv in 5 years) for radiation workers. However, for the general public, the recommended limit is 1 mSv per year.15
  • Pregnant Aircrew: The ICRP recommends a dose limit of 1 mSv throughout pregnancy.16

Current regulations aim to limit radiation exposure for flight crews, but there is room for improvement. The International Commission on Radiological Protection (ICRP) sets guidelines for radiation protection and also includes dose limits for occupational exposure. However, these guidelines may not adequately address the unique challenges faced by flight crews. To improve current radiation safety regulations for aircrews, a multi-faceted approach is necessary. This should include:

Improved Monitoring and Data Collection

Implementing advanced radiation monitoring systems on aircraft in addition to encouraging the use of personal dosimeters by flight crews can provide more accurate and comprehensive data on exposure levels17. This information can help refine risk assessments as well as guide the development of more effective protection strategies.

Aircraft Shielding and Design

Continued research into advanced shielding materials in addition to aircraft design modifications can help reduce the radiation dose received by flight crews and passengers18. This may also involve the use of novel composite materials or the incorporation of additional shielding in critical areas of the aircraft.

Route Optimization and Flight Planning

By carefully planning flight routes and altitudes, airlines can minimize exposure to cosmic radiation, particularly during solar particle events19. This may also involve rerouting flights to lower latitudes or reducing flight time at higher altitudes when necessary.

Education and Awareness Programs

Providing flight crews with comprehensive information about the risks of cosmic radiation exposure in addition to the importance of proper protection measures can empower them to make informed decisions about their health and safety20. This should include training on the use of personal protective equipment, such as dosimeters, as well as guidelines for managing exposure during pregnancy.

Regulatory Harmonization and Enforcement

Strengthening international collaboration to harmonize radiation protection standards for flight crews in addition to ensuring consistent implementation and enforcement of these standards across the aviation industry can help create a safer working environment for all aircrews21.

Conclusion

Although no regulations officially set dose limits, radiation exposure is still a concern to be evaluated for airplane flight crews due to their occupational exposure to cosmic radiation. While the specific health risks associated with this chronic low-dose exposure remain uncertain, continued efforts are essential ensure a safe working environment. By implementing measures such as personal dosimetry devices, increased monitoring, staff training, and encouraging airplane manufacturers to consider shielding and design modifications, airlines can better protect their flight crews. Ensuring a safer career for every radiation worker will require time, dedication, and collaboration. However, the benefits for the health and safety of all industries, including aircrews, make it a worthwhile endeavor.

Versant Physics is a full-service medical physics and radiation safety consulting company based in Kalamazoo, MI. Contact us for all of your regulatory, radiation safety, and personnel dosimetry needs.

Sources

  1. Friedberg, W., & Copeland, K. (2003). What aircrews should know about their occupational exposure to ionizing radiation. Oklahoma City, OK: Civil Aerospace Medical Institute, Federal Aviation Administration. ↩︎
  2. United Nations Scientific Committee on the Effects of Atomic Radiation. (2008). Sources and effects of ionizing radiation: UNSCEAR 2008 report to the General Assembly, with scientific annexes. New York: United Nations. ↩︎
  3. Validation of modelling the radiation exposure due to solar particle events at aircraft altitudes. Radiation Protection Dosimetry, Volume 131, Issue 1, August 2008, Pages 51–58. https://doi.org/10.1093/rpd/ncn238 ↩︎
  4. Wilson, J. W., Townsend, L. W., Schimmerling, W., Khandelwal, G. S., Khan, F., Nealy, J. E.,  & Norbury, J. W. (1991). Transport methods and interactions for space radiations. NASA Reference Publication, 1257 ↩︎
  5. O’Sullivan, D. Exposure to galactic cosmic radiation and solar energetic particles. Radiat Prot Dosimetry. 2007;125(1-4):407-11. https://pubmed.ncbi.nlm.nih.gov/17846031/ ↩︎
  6. Turner, R. E. (2007). Solar particle events from a risk management perspective. Radiation Protection Dosimetry, 127(1-4), 534-538. ↩︎
  7. Lantos, P., & Fuller, N. (2003). History of the solar particle event radiation doses on-board aeroplanes using a semi-empirical model and Concorde measurements. Radiation Protection Dosimetry, 104(3), 199-210. ↩︎
  8. Cosmic Radiation Exposure for Casual Flyers and Aircrew, https://www.arpansa.gov.au/understanding-radiation/radiation-sources/more-radiation-sources/flying-and-health ↩︎
  9. National Research Council. (2006). Health risks from exposure to low levels of ionizing radiation: BEIR VII phase 2 (Vol. 7). National Academies Press. ↩︎
  10. CDC – Aircrew Safety and Health – Cosmic Ionizing Radiation – NIOSH Workplace Safety & Health Topics. Centers for Disease Control and Prevention. Published 2019. https://www.cdc.gov/niosh/topics/aircrew/cosmicionizingradiation.html ↩︎
  11. Pukkala, E., Aspholm, R., Auvinen, A., Eliasch, H., Gundestrup, M., Haldorsen, T., & Tveten, U. (2003). Cancer incidence among 10,211 airline pilots: a Nordic study. Aviation, Space, and Environmental Medicine, 74(7), 699-706. ↩︎
  12. Rafnsson, V., Hrafnkelsson, J., & Tulinius, H. (2000). Incidence of cancer among commercial airline pilots. Occupational and Environmental Medicine, 57(3), 175-179. ↩︎
  13. Hammer, G. P., Blettner, M., & Zeeb, H. (2009). Epidemiological studies of cancer in aircrew. Radiation Protection Dosimetry, 136(4), 232-239. ↩︎
  14. Olumuyiwa A. Occupational Radiation Exposures in Aviation: Air Traffic Safety Systems Considerations. International Journal of Aviation, Aeronautics, and Aerospace. Published online 2020. doi:https://doi.org/10.15394/ijaaa.2020.1476 ↩︎
  15. International Commission on Radiological Protection. (2007). The 2007 recommendations of the International Commission on Radiological Protection. Annals of the ICRP, 37(2-4), 1-332. ↩︎
  16. International Commission on Radiological Protection. (2000). Pregnancy and medical radiation. Annals of the ICRP, 30(1), iii-viii, 1-43. ↩︎
  17. Bartlett, D. T. (2004). Radiation protection aspects of the cosmic radiation exposure of aircraft crew. Radiation Protection Dosimetry, 109(4), 349-355. ↩︎
  18. Wilson, J. W., Miller, J., Konradi, A., & Cucinotta, F. A. (1997). Shielding strategies for human space exploration. NASA Conference Publication, 3360. ↩︎
  19. Copeland, K. (2014). Cosmic radiation and commercial air travel. Radiation Protection Dosimetry, 162(3), 351-357. ↩︎
  20. International Civil Aviation Organization. (2012). Manual of Civil Aviation Medicine. https://www.icao.int/publications/Documents/8984_cons_en.pdf ↩︎
  21. International Atomic Energy Agency: Cosmic radiation exposure of aircrew and space crew. https://www.iaea.org/sites/default/files/20/11/rasa-cosmic.pdf ↩︎

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