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Reports show that ionizing radiations such as X-rays and gamma rays are risk factors for cancer development. These ionizing radiations carry a high amount of energy that can damage the DNA, leading to cancer. Both pets and their owners are susceptible to the harmful effect of ionizing radiation. 

What are ionizing radiations?

X-rays and gamma radiation are high-energy ionizing radiations that can easily penetrate living cells and tissues and damage the DNA. Fortunately, the cells have evolved several mechanisms to detect and repair such DNA damage. However, if there are defects in the DNA repair mechanisms, cells may grow uncontrollably, leading to cancer. Commonly used units of measurement to determine the extent of radiation exposure include the roentgen (R) and the radiation absorbed dose (rad). R is a measure of the quantity of ionizing radiation present in the air, and rad is the amount of energy absorbed in any substance after exposure to ionizing radiation. 

What are the sources of ionizing radiations?

Natural sources: Radon gas generated from the natural decay of radioactive elements (uranium and radium) found in nearly all rocks and soils is the largest source of radiation exposure to humans and pets. Radon may collect in areas in contact with the ground, like basements. Other natural sources include cosmic rays from the sun and stars that hit the earth. Cosmic radiation levels increase as you get closer to its origin, so the amount of cosmic radiation generally increases with elevation.

Manufactured sources: Artificial sources of X-rays include nuclear energy power plants, medical imaging tests, cancer treatments, food irradiation, and airport security scanners. Artificial sources of gamma rays are nuclear power plants. 

Radiation in cancer treatments

If your pet is diagnosed with cancer, one treatment option your vet may recommend is radiation therapy. Studies have shown in humans that radiation therapy has been linked to a higher chance of developing secondary kinds of cancer. It is important to remember, however, that the benefits of radiation therapy to treat cancer usually outweigh the risk of developing different cancer. Radiation treatment rarely causes secondary cancer on its own. Even in these rare cases, it takes a long time for secondary cancer to develop in a pet that has undergone radiation therapy. This is usually because the vet takes special care to concentrate the radiation only on the cancer cells, limiting the danger of developing another cancer. Talk with your vet if you are concerned about your pet’s radiation exposure and discuss the benefits of radiation therapy.


X-rays and gamma radiation can damage the DNA of your pet’s cells and put them at risk for cancer development. However, this risk is low. But understanding how your pet may be exposed to these ionizing radiations allows you to take preventative measures to reduce their exposure and give them a lifetime of health and wellness.

The Pet Cancer Foundation’s Website Editorial team is comprised of veterinarians, veterinary oncologists, and veterinary technicians, as well as scientific writers and editors who have attained their PhD’s in the life sciences, along with general editors and research assistants. All content found in this section goes through an extensive process with multiple review stages, to ensure this extended resource provides pet families with the most up-to-date information publicly available.

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Last Updated: October 11, 2022

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The following sources were referenced to write the content on this page:

Cuttler, JM 2007, ‘Health effects of low level radiation: when will we acknowledge the reality?’, Dose-response, vol. 5, no. 4, pp. 292-298.

Gilbert, ES 2009, ‘Ionising radiation and cancer risks: what have we learned from epidemiology?’, Int J Radiat Biol, vol. 85, no. 6, pp. 467-482.

Hooser, SB 2018, ‘Radiation emergencies: dogs and cats’, Vet Clin North Am Small Anim Pract, vol. 48, no. 6, pp. 1103-1118.

Spatola, GJ, Ostrander, EA & Mousseau TA 2021, ‘The effects of ionizing radiation on domestic dogs: a review of the atomic bomb testing era’, Biol Rev Camb Philos Soc., vol. 96, no. 5, pp. 1799-1815.

Vaiserman, A, Koliada, A, Zabuga, O & Socol, Y 2018, ‘Health impacts of low-dose ionizing radiation: current scientific debates and regulatory issues’, Dose-response, vol. 16, no. 3, pp. 1559325818796331-1559325818796358.

The Pet Cancer Foundation’s medical resource for pet owners is protected by copyright.

For reprint requests, please see our Content Usage Policy.