Can Exposure to Radiation Cause Leukemia?

Can You Get Leukemia From Ionizing or Non-Ionizing Radiation?

Can exposure to radiation cause leukemia?. Credit: © Maggie Dziadkiewicz | Dreamstime.com

Can exposure to radiation cause leukemia?  What kinds of radiation are dangerous and how can you know if you are safe?

Radiation as a Cause of Leukemia

Radiation can and does cause leukemia, but before panicking, we'll talk a little about the types of radiation exposure that can be dangerous. Some types of radiation are known to cause cancer, while others are not. Every day our bodies are exposed to radiation in the form of x-rays, medical diagnostic equipment, microwaves, cells phones, radio waves, and even the rays of the sun, yet not everyone develops leukemia.

Let's start by distinguishing the different types of radiation.

Types of Radiation

There are two main types of radiation:

  • Non-ionizing radiation:  - This type of radiation is weak, and is what is emitted from your cell phone and your computer screen.  While there are some concerns with non-ionizing radiation, for example, the increased risk of brain tumors that has been noted in heavy cell phone users, the risk of leukemia is considered very small.
  • Ionizing radiation: This type of radiation, on the other hand, has much more energy. In fact, it has enough energy to break certain chemical bonds, remove electrons from atoms, and damage DNA in our cells that can lead to cancer. All cells in our bodies can be injured by exposure to this type of radiation.

Sources of Ionizing Radiation

Ionizing radiation is all around us and can cause cancer. Sources may include:

  • Medical radiation: x-rays, CT scans, PET scans, bone scans, mammograms and more
  • Tobacco products: primarily from radioactive material in the soil in which it is grown
  • Decomposition of radioactive materials in rock and soil
  • Radon: Radon is an odorless, colorless gas that is released by the normal decay of uranium in the soil beneath our homes in our homes.  Radon is the second leading cause of lung cancer after smoking, but it is unknown exactly what its role is in leukemia

Measuring Radiation Exposure

Scientists use two primary terms when discussing levels of ionizing radiation exposure. These are considered basically equivalent. The millisievert (mSV) and the milligray (mGy).  For those who work in occupations with exposure to radiation, the​ exposure limit is 50 mSv in 1 year, or 100 mSv over 5 years.

Leukemia and Ionizing Radiation

Leukemia is one of the most common types of cancer that develops after exposure to radiation and is usually diagnosed within 2 to 5 years. Other types of cancer, such as myeloma, may take as long as 15 years to develop.

Ionizing radiation was found to be carcinogenic (or cancer-causing) only a few years after X-rays were discovered. Early scientists began keeping track of illness among radiation workers and noticed an obvious link between radiation exposure and cancer. More recently, the populations of people exposed to radiation during the Hiroshima and Nagasaki atomic bombings, uranium miners, and people who were treated for medical conditions using radiotherapy have been studied to confirm the connection.

Leukemia and Medical Radiation: Don't Panic But Ask Questions

We know that medical radiation can lead to cancer. Most of the time, however, the risk is very small and totally acceptable when compared to the benefits.

Much of our knowledge comes from those who have had radiation therapy for cancer.  Radiation therapy in this setting may increase the risk of leukemia down the line by a small amount, but can have great benefits in treating a cancer currently present.

Concern arises when talking about tests that are done on many people - tests that in some cases may have an alternative (such as ultrasound or MRI) which does not confer the cancer risk of radiation.  Exposure to medical radiation has increased significantly in the United States.  In 1982 the average American was exposed to 0.5 mSv per year.  By 2006 that had risen to 3.0 mSv per year - a 6-fold increase in exposure attributed largely to medical radiation.

We don't now exactly how significant the radiation exposure from diagnostic tests is, but estimates have been made based on atomic bomb exposures.  Based on this analysis, it's thought, according to the FDA, that exposure to 10 mSV increases the risk of death from cancer by 1 in 2000.

Recently, there has been a push to reduce the number of unnecessary CT scans, especially in children, who due to their age are at a higher risk from exposure.Check out these questions to ask if your child has a CT scan. In order to have an idea about radiation you may be exposed to, here are some examples:

  • Airplane flight (cosmic radiation) - 0.005 mSV/hour in the air
  • Chest x-ray (2 view) - 0.10 mSV
  • Chest CT scan - 8.0 mSV
  • Abdominal CT scan - 10.0 mSv
  • Mammogram - 0.7 mSV

Is There a Safe Level of Exposure?

While populations such as those that are exposed to high levels of radiation over a relatively short period of time are easy to track and study, scientists know very little about the risk to people who are exposed to constant low levels of radiation. All of us are subjected to a certain amount of radiation every day, but we do not all get cancer. Researchers do not know how much is too much radiation and which levels are considered “safe” amounts of exposure.

Sources:

American Cancer Society. Do x-rays and gamma rays cause cancer? Updated 02/24/15. http://www.cancer.org/cancer/cancercauses/radiationexposureandcancer/xraysgammaraysandcancerrisk/x-rays-gamma-rays-and-cancer-risk-do-xrays-and-gamma-rays-cause-cancer

Djomina, E. and Barilyak, I. "Medical and Genetic Consequences of Radiation Catastrophes" Cytology and Genetics 2010. (44)186-193.

Environmental Protection Agency. "Radiation Protection" https://www.epa.gov/radiation#riskofcancer Updated 09/16/15.

World Health Organization. (2006) "Health Effects of the Chernobyl Accident and Special Health Care Programmes" http://apps.who.int/iris/bitstream/10665/43447/1/9241594179_eng.pdf Accessed 03/05/16.

Yarbro, J. Carcinogenesis. In Yarbro, C., Frogge, M., Goodman, M. and Groenwald, S. eds (2000). Cancer Nursing: Principles and Practice 5th ed Jones and Bartlett: Sudbury: MA (pp. 48-59).

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